BeerLab Home Brew Supplies

Adding oak flavour to your beer

As winter draws closer we are starting to enjoy darker, heavier beers at the braai and around the fire. Dark Ales, Porters, Stouts, Imperial IPA's, 90 shilling etc are all firm favorites. More recently we have also seen barrel aged beers grow in delicious popularity.


Oak compliments so many beer styles perfectly (just look at the Oaked Aged Innis and Gun range).


So how do you add oak flavour to you beer?

Most home brewers do not own a oak barrel but using oak chips is a cheap and easy way to add to add oak to your beer.

Oak chips have a large surface area, which means it lends its flavour quickly.

There are 3 different oak varieties available today - American, Hungarian and French.

American oak will provide the strongest oak flavour while French oak is much softer, with a sweeter, vanilla flavour. (Hungarian falls in between the American and French varieties)

The more toasted your oak chips the darker the colour will be - a heavy toast will add a more cabonized flavour.

At BeerLab we have American and French oak chips on offer. Both of these varieties are available in Mini Chip (Coarse) and Vini Oak (Finer).

The finer the oak chip the greater the surface to area ratio - resulting in a faster flavour transfer.


So how do you use oak chips?

A - You can add the chips directly to your fermenter

This is the most common method.  Oak chips are added to a weighted bag (remember to sterilize the bag too) and dropped into the fermenter. Oak aging can take anywhere from a few days to several months depending on oak used and desired flavor level.

B - Infuse the oak chips

Infusing avoids having actual oak chips in your fermenter. This is also the fastest flavour transfer method. It is however very important to only do this post fermentation - preferably in a secondary fermenter.

You can infuse in two ways. Firstly you can make a oak 'tea' - This is done by boiling oak chips for at least 10 minutes in enough water to cover (about 1 cm), straining out the chips, and adding the resulting 'tea' to your fermenter. An advantage to this method is that you can you can blend it to your liking adding oak tea according to taste. 

The second way to infuse oak chips involve alcohol. For a base oak flavour the chips can be soaked in vodka to extract the flavour - the chips will need to steep for a week. If you would like to add a whiskey or bourbon flavour you can infuse your oak chips in whiskey/bourbon. The strained oak 'extract' can then be added directly to your fermenter prior to bottling (taste and adjust depending on how much oak flavour you want)


Finally, If you find the oak flavour to harsh or tannic you can consider doing a two stage soak in alcohol - soak and cover for the chips a few days, discard the liquid from the first soak and top up with fresh vodka/whiskey before soaking for another week.

Bourbon porter anyone? 

Written by Lynnae Endersby — May 12, 2017

DIY Biltong maker

Making your own biltong box is very easy and inexpensive. Anyone can do it!

What you will need:

  • A box - Free
  • USB fan - approx R110. These can be purchased at most retail stores like Clicks. You can also buy them on
  • A plug for your usb fan - Free (this can be a computer/laptop or standard android USB charger) see below


  • Zipties/Cable ties (you need about 15) - R5
  • Newspaper (Free)
  • Cheesecloth or Mesh (to keep biltong hungry bugs away) - R8
  • Optional - Cupboard airing discs (the white discs in the photos - they cost about R3 each)
  • A Dowel stick (wooden rod) - R8 (see below)


Total cost =  .R131

Step 1

Tape the underside of the box closed. Line the bottom with a few layers of newspaper (this will catch any spices or drops of marinade that falls off the biltong while it dries).

Step 2

Cut two large windows on each side of the box (approx 30 cm x 15 cm) - Stick Cheesecloth (we prefer this one - available at CheeseLab  or a mesh over the windows with some tape (duct tape works well). The windows will let air circulate to help dry the biltong.


Step 3

Cut a hole in the bottom of the box to fit the fan. The hole should be small enough to you can squeeze the fan in (any excess space will need to be filled as bugs will be able to get to your biltong). Tie the fan to the box with zip ties to keep it secure.


Step 4

Use a pencil or something sharp to make holes for the dowel sticks to fit into snugly. Make sure you leave enough space between the dowel sticks ( about 6 cm) as the biltong must have air circulating around it and it should not touch other pieces.


Step 5


Step 6

Hang the biltong and switch on the fan. Cover the top with a large cutting board or tape to seal it off (and avoid bugs). Leave the fan running for 3 to 7 days - depending on how dry you like your biltong.


Written by Lynnae Endersby — February 24, 2017

Designing your own recipe 101

My first brew I ever did was all-grain, back in 2009. All I had to work with was SAB pale malt, SAB black patent malt and SAB Southern Promise hops. My yeast was the high foam super brew brand from NCP. As you can tell, back then, we did not have much access to the massive range of specialty malts, hops and yeast that we now get. And when we did, it had to be posted, which took weeks to arrive, and more often than not, the box had lost most of the grain after being battered around en route, and the hop bags were usually opened as they looked like suspicious contraband. We’ve come a long way since then, thankfully. We now have access to a massive range of ingredients, and it is only getting better and fresher. It’s a great time to be brewing!

Knowing how to use these great ingredients most effectively is an art, and it does take practice. My first few brews were amber lagers, brown porters, and oatmeal stouts. All of them tasty beers, but none even vaguely like their aimed style. Those brews were not unlike those days when I experimented with baking as a kid. I only had flour, milk and sugar to play with, so I learnt what ratio gave you the tastiest end product. Even though I couldn’t call it a cake, it was still edible.

But the more I brewed, the better I got at achieving those aims, in a fewer numbers of attempts. This is a skill that comes with practice, much like the way a chef perfects the art of balancing spices and herbs in a dish. However, the best place to start is by scouring the internet for recipes uploaded by fellow brewers. Unfortunately, some of those recipes have grain, hops, and even yeast listed that are not available in South Africa, which does often put brewers off those particular recipes. Thankfully, most maltsters are producing varieties that are similar in colour and flavour as some of their counterparts. For example, Weyermanns does a lovely malt called Munich Malt Type 2 (20-25 EBC), and Castle Maltings does their equivalent called Château Munich (25 EBC). The internet is full of grain and hop substitution charts to help guide you along the way.


First off, invest in brewing software, such as BeerSmith. This makes the design process much easier as it gives you the ability to input your equipment profiles, whether it be BIAB or 3-tier. BeerSmith also has a bunch of pre-loaded tried-and-tested recipes for you to play with. Most of these brewing programs do require a once off fee, but it is worth the investment for a successful brewing experience, as well as good record keeping, which is also extremely important.


Secondly, join your local home-brewing group, and chat to as many brewers as possible. There are also loads of online brewing forums, such as on Facebook, filled with brewers eager to help. Don’t be daunted by the act of getting involved. Even the most experienced brewers started their careers by fumbling around, not knowing what ingredients to use, and when to use them.  

When you first start designing your own recipes, make sure you allocate yourself plenty of time. You will need to research each ingredient thoroughly and when to add it. Every time I compile a recipe, I tend to follow these steps:

  • Decide what your target style is. For example, do you want something rich and malty (such as a brown porter) or something crisp, bitter and hoppy (such as an American ale)?  

  • The next step is to look up that particular style in the BJCP 2015 guidelines. This guide provides detailed specifications on all the styles, and also suggests ingredients commonly used in those styles. It also gives you the ranges of parameters that make it fit into that particular style category, such as bitterness (IBU’s), original/starting gravity (OG) and colour (EBC/SRM) which assists you in achieving the correct balance to your beer. Often, your brewing software, such as BeerSmith, already has these parameters set up for you, which makes the design a little easier. Of course, you are not limited to producing only BJCP beer styles, but it is an extremely useful guide to point you in the right direction. 

  • The next step is choosing your ingredients. The BJCP guide is also helpful in suggesting what grains to use, but unfortunately, it doesn’t give you much info on how much of each to use. This is where the internet is a great resource. In particular, BeerSmith’s recipe blog page, and Brew Your Own ( style pages. Another great resource is the book by Ray Daniel’s, Designing Great Beers. This book provides detailed information on grains and hops used in popular commercial beers as well as award winning versions of particular styles. You will also need to decide what yeast you want to use. There are many yeast strains (liquid and dehydrated) available from brew stores, suitable for a wide variety of different styles (remember, most yeast strains have specific temperature ranges that they prefer to ferment at). Also, don’t be afraid to post your recipe on brewing forums to get feedback from others. Experienced brewers are always keen to help. Podcasts are also a great source of information, in particular, The Brewing Network (Can You Brew It) where you can get the recipes for popular commercial beers, such as Fuller’s London Pride.

  • Input your equipment profile onto your brewing program. This is very important, as it will help ensure you hit your target gravity and colour. 

  • Next, you need to enter the ingredients into your brewing program. The important things to note are: 
  1. Bitterness (IBU’s): this is the amount of bitterness in your final product from the addition of hops- you would balance this based on the beer style. The longer you boil the hops the more bitterness develops, and the more the hop aroma will boil away. If you are looking for more hop flavour and aroma, consider doing end-of-boil, whirlpool, or dry (fermenter) hop additions.  
  2. ⦁ Bitterness ratio (IBU:GU): this is useful to establish your bitterness to malt ratio- this ratio differs depending on the beer style. It provides a good indication of how balanced your beer will be.
  3. Colour (SRM/EBC): this changes based on what grains you use.
  4. ⦁ Original gravity: basically, this is how much sugar, obtained from the malt, is available for the yeast to convert in to alcohol.
  5. ⦁ Final gravity (FG): Gives you a prediction of how attenuative the yeast you are using is- will you get a dry beer or a slightly sweeter finish to the beer.
  • Once you have entered your ingredients, you need to decide what mash temperature to use (are you looking for a beer with a dry or richer/sweeter finish?).

  • Take good brewing notes throughout the process. Keep track of every aspect of what you did. Once the beer is ready to drink, take tasting notes as well. That way you can keep track of what you did right and what you need to change in future brews

It might seem daunting at first, but experimenting with different ingredients and parameters is what makes brewing fun. Using recipes available online as a guide is a great place to start, and from there, you can tweak the recipes as you wish to suit your personal preferences. Don’t be afraid to get other people’s feedback either, particularly from knowledgeable brewers. Take a few bottles around to your next home-brewers meeting, and chat about it. Find ways of improving it and brew it again. It is the best way to grow your hobby and get your beers tasting better and better. Also be confident to enter your beers into home brewing competitions. That way, you can get constructive feedback from accredited judges. More often than not, the judges will offer practical ways in which to improve your beers, whether it be an ingredient modification, or a brewing technique modification. Don’t be afraid to experiment and to ask for help! 


Written by Megan Gemmell — February 23, 2017

The removal and prevention of beer stone

This is an article I have been wanting to write for a while.

I, unfortunately, only learnt about beer stone the hard way.

The quality of beer coming out of my kegs was inconsistent from one keg to another. Some were perfect, while others kept developing off flavours and very high carbonation within a few weeks after kegging. It was a depressing amount of beer to be throwing away, and even more frustrating as I didn’t know what was going wrong. What I did know however, it was a sure sign that something was living in those kegs that shouldn’t have been. I thought it must have been something in my keg filling regime, but that didn’t explain why some kegs were fine, while others not. My keg cleaning always followed a strict hot alkaline cleaning protocol, followed by sanitising with Supersan (acetic acid based santiser) or Imperisan (phosphoric acid based sanitiser). I really thought I couldn’t be any more thorough. But I was still stumped.

On closer inspection, I realised that all my kegs that I had bought brand new, were not going off, while my second hand kegs were the ones developing these off flavours, even with their rigorous cleaning regime. When I removed the keg spears (which is not recommended), I soon realised what the problem was.

From the images below, you can see the build-up of a chalky grey-white scale on the spear threads. I knew this was the cause. It was beer stone...

Both the alkaline cleaners and acid sanitisers were not going to get into this thread enough to remove this build up, and even if they did, they would not remove this scale. This scale does not come off with a standard soak and scrub. I soaked the spears in a strong phosphoric acid/nitric acid solution (used in the dairy industry against milk stone) with intermittent scrubbing with a hard toothbrush, for weeks, and only then did it start to come off. This made it very clear to me that our simple cleaning practices are not sufficient to get rid of beer stone. When it comes to beer stone, prevention is better than treatment. It is worth the time and effort to avoid throwing, what was initially good beer, away.

What is beer stone?

It is a precipitate of calcium oxalate and protein. It can be found on the inside of your fermenters, as well as kegs, heat exchangers, aging tanks, beer dispense lines etc. Basically, everything that comes into contact with wort and beer.

How does it form?

Organic compounds (proteins and polypeptides) in wort and beer bind with the compounds found in the brewing water (calcium and magnesium) to form calcium oxalate, a white crystalline precipitate. Microorganisms can live and multiply in this precipitate, protected from standard cleaning processes.

It is also important to note that most breweries use caustic (NaOH) in their cleaning protocol, and unfortunately, this also contributes to beer stone formation (caustic reacts with carbon dioxide, usually in high concentrations in kegs and fermenters, to form a precipitate).

Effects of beer stone

Beer stone is not like the usual hard water scale that we see developing in our kettles and shower heads (largely calcium and magnesium based deposits). Beer stone also contains proteins which acts like a binding agent, which makes the scale much more hardy and therefore, more difficult to remove. This beer stone creates loads of places for microorganisms to “hide”, making it impossible to sanitise, so when your wort or beer is added to the vessel, it creates a perfect environment for the nasty critters to thrive. The effects might be minor changes in flavour profile, or major contamination issues, depending on the scale problem.

How do I remove beer stone?

Prevention is better than treatment. Once you can actually see the beer stone, you will have a very difficult time getting rid of it. You will need to use the chemicals used in cleaning at concentrations in their upper level of their recommended dose, and for a longer time.

Of course, you do need to approach an accredited chemical company for the recommended treatment of your vessels. This blog is merely a guide to create awareness of potential problems in your brewery. There are many chemicals on the market, most of which do not actually state what their active ingredients are, so rather do approach someone that is trained in this field. These chemicals can give off harmful by-products if mixed incorrectly.

As previously mentioned, caustic can actually cause the build-up of beer stone, so some breweries add sequestrants (chelating agents) such as EDTA to the caustic cleaners to prevent the precipitation of the calcium components, which ultimately form beer stone.

I have tried the following method suggested by More Beer, which is also commonly used by some breweries, and got great results (not without some serious scrubbing however). It uses a two-step approach: an alkaline cleaner to “digest” the protein, followed by an acid detergent to dissolve the minerals. Most cleaning regimes used to remove beer stone involve both an acid and alkaline (non-caustic) step.

Step 1: Rinse the vessel with ambient-temperature water.

Step 2: Use a phosphoric/nitric acid mixture as prescribed (maximum 60°C) for 15-30 minutes.

Step 3: Don’t rinse.

Step 4: Use a non-caustic alkaline cleaner as prescribed. CIP for 15-30 minutes, depending on conditions.

Step 5: Rinse with ambient-temperature water until the pH of the rinse water is the same pH as the tap water coming in.

If you are still not able to remove the beer stone, you may need to approach more hardy tactics. I find the dairy industry is full of options due to their similar problem with milk stone.

Of course, these chemicals are all hazardous, so again, I suggest you do speak to an accredited expert, as well as implementing all the safety measures.


Beer stone can creep up on you very suddenly. It may start off, initially, as some slight off flavours or aromas in your beer, not enough to say it was off, but enough to know that something in the processing may be going wrong. If left untreated, you will end up with a major problem, one which is difficult to get rid of, and you will have a lot of wasted beer in the process. Beer stone is NOT just something you MIGHT have to deal with when buying second hand equipment, no, it is something even your new equipment will eventually have if you do not follow good cleaning measures. When a pub is serving your beer on tap, and one keg is perfect, while the next is bad, who is at fault here? Of course, it is difficult to say, there are so many aspects to consider, but is it the barman for storing the keg wrong, etc etc, or maybe your keg was actually riddled with beer stone, and has now become infected? Definitely worth considering.


Removing & Preventing Beerstone Buildup. 2014. Accessed 11 July 2016. Originally Published by Steve Parkes - Brewing Techniques (Volume 6, Number 4).

Garrett Oliver. 2011. The Oxford Companion to Beer. Oxford University Press, USA, 09 Sept 2011.

Dana Johnson. 1998. Removing Beerstone: a look at alternative cleaning methods. Birko Brewery and Produce Specialist, Modern Brewery Age, March 23. ( Accessed 11 July 2016


More about the Author, Megan Gemmell:

When I am not working as a microbiologist, I am brewing and studying beer. Being the geek scientist that I am, brewing yeast has become one of my main interests. After many years of brewing on my home-made system, squeezed into the laundry, I have taken the plunge and started Clockwork Brewhouse, and I’m loving it. 

Written by Megan Gemmell — July 14, 2016

Houston, we have a blow out!

I think we have all experienced a bubble/blow-over brew at some point in our brewing life, all in varying degrees of disaster. I’ve seen chest freezers absolutely covered in worty mess, but sometimes it’s slightly less disastrous, where it has gone only as far as your bubbler. This is why it always a good idea to have one bubbler spare.



The reason for a bubble over is a lack of headspace in your fermenter and the krausen has escaped. Many brewers forget that high gravity brews (anything above 1.060 OG in my opinion) need extra headspace in the fermenter. But even lower gravity brews can blow over if the fermentation is particularly vigorous, usually caused by higher fermentation temperatures or increased aeration etc.

So what do you do?

Don’t panic! It looks worse than it is. Get a spray bottle of sanitiser and do your best to sanitise and clean the outside of the fermenter and surrounds. Only deal with the bubbler/blow off tube once the fermenter and surrounds are clean and sanitary. You don’t want to open the fermenter at all. Transferring your worty beer into a clean fermenter will only harm your brew at this point. Your fermenter will look like a dog’s breakfast on the inside, but it’s a yeasty/worty/hoppy dog’s breakfast, so rather leave it. You can always transfer into a secondary bucket on bottling day.

Once the outside of your fermenter is clean and sanitised, you can swap over to a clean bubbler, or blow off tube of the same diameter as the bubbler (so that it fits snuggly). When you do this, make sure the replacement bubbler/blow-off tube has been properly sanitised. If the rubber bung that holds the bubbler is also mucky, then I would suggest using a cotton bud or cotton wool, also sanitised thoroughly, to gently swab it clean. Cane or Vodka also works very well for this, if you are worried about the sanitising solution getting into your brew. The opening where the bubbler fits is very small, so it is not likely for any nasties to sneak inside during this process, but I would still try and work quickly, and work in an area that is not too draughty. Replace your bubbler, fill with a little alcohol or sanitiser to create an airlock, and you’re good to go again.

Alternatively you can use a blow off tube, place the end of the tube into a bucket of sanitiser solution so nothing gets into your fermenter via the tube.


Written by Megan Gemmell — March 14, 2016

Making a yeast starter

Growing up your own yeast and maintaining your stocks can be a very daunting concept, but if you follow a few simple steps, you will find that it is not that intimidating. Provided you keep things
sanitary, you will soon be benefiting from the rewards (faster fermentations and cleaner beers) of
pitching live yeast at the correct pitch levels.



  • Erlenmeyer flasks (2 liter is a good size)                
  • Stir plate  
  • Stirrer bar
  • Dry malt extract
  • Yeast nutrient
  •  Hops (your old expired ones will do perfectly)
  • Camping gas stove/Bunsen burner
  • Spray bottle of sanitiser


Sterilizing wort in the flask:

The best starting gravity for your starter is 1.036 to 1.040. You can sterilise your flask, stirrer bar
and wort by simmering directly on your stove top for approximately 45 minutes with a cotton-
wool bung (acts like a filter to stop anything getting in) covered with tin foil, and then a further 40
minutes the following day (a method of tyndallization) (of course, you will need to take into
account any boil-off during this process, and thus you will need to reduce your initial starter
gravity to avoid an OG too high). Adding a few hop pellets into the wort before sterilising adds a
further method of keeping contamination out (hops are a natural antimicrobial agent). You can  also sterilise top-up wort in a pressure cooker if you have one. This acts like a mini-autoclave and is very effective. 


Inoculating your starter with yeast:
You can use either dry yeast (such as Fermentis), or liquid yeast (Wyeast or Whitelabs). To scale
dry yeast up in volume, you would normally follow a rehydration step in 27°C ± 3°C sterile water
or wort for 15-30 mins, and then you would add this yeast to the starter. Liquid yeast has a much
shorter shelf life than the dehydrated yeast, and therefore, more commonly needs a starter.

To ensure your starter stays clean of contamination, there are a few things you can do. Sanitise
your work area around you as well as your hands before starting. Have your Bunsen burner or
camping gas burner lit and close by. Each time you remove the cotton-wool and tin foil bung, you
need to flame the neck of the flask, this ensures that if any contamination is on the neck of the
flask, you will kill it, and it also allows for a steady rise of hot air away from the open flask, to
prevent any bacteria/wild yeast settling on your flask.

If you are growing up a sachet of dry yeast, sanitise the outside of the sachet as well as the scissors you will use to open it, with acidisan (or equivalent). If you are using a liquid culture in a vial, then sanitise the outside of this too. These vials are usually plastic, so you won’t be able to flame the edges of it, you just need to work quickly in decanting it into your flask, and try to work as near to the flame as possible. Once you have added the yeast into the flask, flame the neck of the flask again, and replace the cotton wool and tin foil bung. It is usually required that you let the flask containing the newly added yeast to sit on a table top for approximately 30 minutes, before placing it on the stir plate for the growth stages. You can scale up the yeast even more by adding sterile wort into the flask following the same sterile technique discussed above. If need be, you can decant some of the spent wort from your flask to make space for fresh wort to continue its growth. I always taste the spent wort to get a gauge on how the yeast is doing.

With this, you should be all set to grow your own yeast starters. Good luck!

Written by Megan Gemmell — January 27, 2016

Selecting the “right” yeast

Yeast belongs to the fungal kingdom and are unicellular. There are about 1500 different strains of yeast, but brewer’s yeast is very different to those yeasts found in the wild. Many yeast strains can convert sugar to carbon dioxide and alcohol, but this does not necessarily mean they can make good beer. Brewing yeast has, essentially, been domesticated. In other words, we have purposefully selected for characteristics such as the ability to grow and feed off malted grains quickly, and to provide the desired beer flavours and aromas.

    During fermentation, yeast breaks down simple sugars to harvest energy for its survival, and produces carbon dioxide and alcohol, which for us, are the desired waste products. It is believed that yeast evolved this ethanol-CO2 producing ability, to prevent other microbes from also feeding on the simple sugars, as the very high acidity and alcohol levels make the environment intolerable for most organisms. This is great for us brewers.

    There are hundreds of different strains of brewing yeast, but you want to choose a strain that creates the best flavours in your beer, and not all strains will be suitable to your needs. Both literature and the web are full of helpful information regarding which yeast strain to choose for your beer.

    There are two main species of brewing yeast, namely, ale (S. cerevisiae) and lager (S. pastorianus) yeast, and within these 2 main species, there are many different strains, all producing various characteristics to a beer.

    George Fix helpfully categorised ale and lager yeasts according to their fermentation character (flavours etc) rather than by region:

    • Lager  - Dry/Crisp
                  - Full/Malty
    • Ale       - Clean/Neutral
                   - Fruity
    • Phenolic
    • Hybrid (these beers lie between the ale and lager style)
    • Eccentric (these strains produce unusual flavour compounds such as earthy, barnyard, sour or are high gravity fermenting yeasts.

    Ale strains are top fermenting (produce a large, foamy head/krausen). This is because the ale yeast surfaces are hydrophobic and the yeast cells stick to the CO2 bubbles and rise with them to the surface. They usually ferment at about 18-21⁰C.

    Lager strains are sometimes referred to as “bottom-fermenting” as during fermentation, they don’t rise (or only minimally) to the surface. They are also not usually very good flocculators, so they tend to stay in suspension for longer than the ale yeasts. This allows the yeast to reduce more of the by-products that are formed during fermentation. This results in the “clean lager” character we commonly speak of. They usually ferment between 11 and 12⁰C.

    So, how do you choose? Well, you first need to decide what the overall concept is that you want from your beer. Do you want malty and sweet, crisp and dry, clean or estery (fruity), high or low alcohol etc? Once you have decided, you can begin looking at possible yeast strains. Over the last year or so, new and exciting yeast strains have entered the South African market, so you now have a lot more choice to play with. It is daunting to begin with, but once you know what you’re dealing with, you can have a lot of fun trying the different styles. It really is amazing how much character a yeast strain can impart on a beer (see previous blog). The most important things to consider are:

    • Attenuation (do you want crisp or malty/sweet)
    • Flavour profile (clean, spicy, malty or fruity etc)
    • Flocculation (how well a yeast settles out of suspension)
    • Supply/availability
    • Temperature range (this is important if you don’t have access to temperature control)

    You can chat to your brewing buddies, look at literature, search online, or you can play with the different yeast strains yourself and pick the best one. You can do this by brewing a batch and splitting it into a number of fermenters with different yeast. Once you’ve decided on a strain, you can then manipulate temperature, oxygen levels, pitching rates and determine what has the best effect on your finished beer.

    Most yeast suppliers make our decisions easier by differentiating the yeast by ale or lager first, and then by geographic location (country, city, or region) or by its specific style name (eg: Altbier, California Common etc). Once you’ve narrowed it down, you can decide from there. But don’t limit yourself to just these. You can brew an American pale ale using a European ale yeast, for example. This will set your beer apart from all the other APA’s, and give you a lot more yeast strains to play with. Don’t be afraid to experiment.

    Good luck, and have fun!



    White, C., Zainasheff, J. 2010. Yeast: The practical guide to beer fermentation. Brewers Elements Series, Brewers Publications. 304 pp.

    Reid, A., Ingerson-Mahar, M. 2012. If the yeast ain’t happy, ain’t nobody happy: The microbiology of beer. American Academy of Microbiology, Washington, DC. 13 pp.

    More about the Author, Megan Gemmell:

    When I am not working as a microbiologist, I am brewing and studying beer. Being the geek scientist that I am, brewing yeast has become one of my main interests. After many years of brewing on my home-made system, squeezed into the laundry, I have taken the plunge and started Clockwork Brewhouse, and I’m loving it. 

     Visit Clockwork Brewhouse

    Written by Megan Gemmell — April 22, 2015

    Happy yeast is happy beer: are you pitching correctly?

    Many brewers are daunted by the idea of yeast starters, but with a few basic tips and a bit of practice, you won’t look back. Over the course of the next few months, I will cover the basics of yeast, from propagation, to its health.

    The most important lesson I have learnt while brewing, and I cannot stress it enough, is keeping your yeast happy. Happy yeast is happy beer. It is almost like yeast is the afterthought after a long, tiring day of brewing, and few of us realise the importance of choosing the correct yeast, and knowing how to keep it happy. Many of us are not pitching the correct amount of yeast into our wort. Either we are on a budget, or we are just guesstimating, and don’t really know where to start. Once I discovered the importance of pitching the correct amount of yeast, I have never looked back. I achieved a noticeable improvement in the resulting beer: it fermented faster, aging time was massively reduced (you’ll get to drink it so much faster ), and there was a clear reduction in unwanted yeast by-products, such as acetaldehyde (green apples). In addition to all these benefits, correct pitching rates also help to prevent potential contamination by wild-yeast or bacteria that may have snuck in (such as Pediococcus and Lactobacillus). By starting with a high number of yeast cells, you are reducing the likelihood of any potential foreign microbes from replicating sufficiently to outcompete the brewing
    yeast and become a problem. (However, please note, if your cleaning process is not adequate, no amount of yeast will prevent a contaminated beer).

    First off, you need to remember that yeast is a living organism, and, like us, it needs nutrients and minerals to stay fit, strong and happy. This comes in the form of sugars, nitrogen, amino acids and fatty acids (majority of which comes from the malt, but also from specific yeast nutrients such as the
    Servomyces Yeast Nutrient). In addition, yeast, like us, does not perform well under stress. Yeast can be stressed by numerous things, such as high sugar concentrations, low pitch rates, incorrect reproduction/fermentation temperatures, pH etc. Ensuring you have created the best environment for
    the yeast, you will massively improve the quality of the resulting beer.

    For the purposes of this blog, I am going to concentrate on pitching rates.
    Mr Malty (  is an invaluable tool to help you calculate the correct pitching rates for your brew. After playing with the calculator, you will soon see that the suggested pitching levels stated on most dehydrated sachets of brewing yeast are actually too low (11.5g per 20-30 liters). To use an example, you need 10g of dry yeast for 20 liters of 1.050 gravity wort. Baring in mind, this is using yeast that was produced on the 3 March 2015 (maximum viability).


    However, most dry yeast we purchase are already a few months old. So remember to take that into consideration, as you will then need to pitch more yeast. For a 6 month old sachet, you would then need 12g of yeast.


    Lagers require a higher pitching rate than ales (the reasons will be covered in a future blog). For a 20 liter lager of 1.050 starting gravity, you need 21g of dehydrated yeast (of the same viability as the ale as previous). This is over double the amount of yeast that is required for an ale. (Remember, stronger beers also require a higher pitching rate).

    And for a 6 month old sachet, you will need 23g for your 20 liter lager.

    Under pitching causes the yeast to reproduce a lot more than a higher pitch would, before all the resources are consumed. This results in a beer that has more yeast character (esters etc.), while those beers that are pitched higher tend to have a cleaner fermentation with less yeast character.

    Belgian-style and wheat beers (eg. Weiss) add a whole new aspect to your approach to yeast however, and defy everything I have just told you. What makes these beers unique, is their fruitiness (eg. banana- called esters) and their spiciness (clove-like- called phenols). What gives these beers their
    characteristics, is playing with the fermentation temperatures, their starting gravity, and pitching rate and achieving the correct balance. Higher fermentation temperatures results in more esters produced (more fruity/banana like aromas), while more phenols are produced at lower fermentation
    temperatures (spice/clove-like aromas). Some Belgian breweries start at a lower fermentation temperature for phenol production, and then allow the fermentation temperature to slowly increase, thereby increasing the production of esters. Each brewery has their own balance of esters/phenols for
    their beer. Just a side note, don’t ever decrease the fermentation temperature once fermentation has begun, this causes the yeast to go into survival mode, and drop out or go to sleep (stuck fermentation) (yeast does not like to be wrangled). You may need to re-pitch with healthy yeast. (As a home-brewer, it is advised to stick with the suggested fermentation temperature for your specific yeast). In addition, a reduction in your aeration will increase the production of esters, while increased aeration will reduce esters. Pitching rates also alter ester production. Some brewers like to under-pitch to increase fermentation characteristics in their beer. It is all about achieving a balance between all these parameters to reach your goal profile.

    After saying all this, there is also such a thing as too much yeast. Extreme over pitching causes the yeast to consume the nutrients too quickly, causing starvation, the build-up of unused metabolic products and yeast death, all of which will add unwanted characteristics to your finished beer.

    Of course, pitch rate is just the beginning of the yeast story. Yeast health, available nutrients, pH and fermentation temperature are all contributing factors in achieving great beer, but realising yeast is a living organism that needs a little TLC (tender, loving care) is the first giant step in the right direction to achieving great beer. Till next time, keep on beering! Megan


    More about the Author, Megan Gemmell:

    When I am not working as a microbiologist, I am brewing and studying beer. Being the geek scientist that I am, brewing yeast has become one of my main interests. After many years of brewing on my home-made system, squeezed into the laundry, I have taken the plunge and started Clockwork Brewhouse, and I’m loving it. 

     Visit Clockwork Brewhouse


    Written by Megan Gemmell — March 10, 2015

    It floats! A practical guide to using your hydrometer effectively!


    Of the two scientific instruments most commonly used by home brewers the hydrometer is certainly the least well understood. We all understand thermometers -temperature degrees are a part of everyday life. But what about relative density, specific gravity or degrees Plato? And then there’s that mysterious meniscus!  Using a hydrometer correctly takes much of the guess work out of brewing and is an indispensible measuring tool. This article will explain how -and also when- to use your hydrometer, to really get the most from it!

    For brewers the hydrometer achieves three simple tasks. It allows a way of determining the sugar content of the wort; monitor the progress of fermentation, and, with some simple maths, to calculate the alcohol content of the finished brew. For grain brewers, it can also help measure how efficiently the mash extracts sugars.

    A hydrometer reading is literally a calibrated measurement of how high (or low) it is floating in our wort or beer. This reading is higher in denser liquids, and lower in thinner ones. -So what makes a liquid denser? In this case it is dissolved maltose sugar (and some dextrin) that float the hydrometer higher, and later, as yeast gradually depletes the sugar, drop it lower.  Pretty simple- but how do we make this work for us?

    Calibration, readings and temperature

    Firstly let’s take a closer look at how hydrometers are calibrated. Specific Gravity (S.G.) is how home brewers measure the density of their wort or beer. This is a weight measurement, and is relative to pure water, which represents a reading of zero; this is written in Specific Gravity as 1.000. A 10 percent weight of sugar to weight of water gives us a reading of 1.040. The S.G. is often written as 1040 or simply 40.  Brewers simply refer to this as a ‘gravity reading’, and use two common abbreviations according to when the readings are taken during the brewing cycle. They are:  Original Gravity (O.G.) and Final Gravity (F.G.). The O.G. reading is taken before fermentation commences and the F.G. at the very end.

    So how do we actually take a reading? A hydrometer is supplied (usually) with a tall measuring flask. This holds enough liquid to float the hydrometer in without it touching the bottom. A sample of wort or beer is taken and the hydrometer floated in it (this is best done over a sink). Place on a counter and wait a few seconds for it to come to rest. Then take a reading from the surface of the water- not where the water meniscus reaches up! You now have a specific gravity reading- remember to write it down on your recipe sheet!

    A quick word about the temperature:  Modern hydrometers are typically calibrated to read at 20C and a higher or lower temperature liquid affects the accuracy. In practical terms a few degrees either way is not that noticeable, but larger jumps of 5-10 degrees should be taken into account. A warmer temperature of 32C (typical of warm wort) would give a difference of plus 1.003. Our reading of 1.040 would actually be 1.043.  This is because warm dissolved sugar isn’t as dense, and this affects the reading. Cooler temperatures give the opposite effect- at 10C you would minus 1.002 from 1.040 giving you 1.038. A calibration chart or online calculator is useful to make adjustments when necessary.

    What to expect

    Brewers take an Original Gravity sample reading before the fermentation has begun and the temperature is close to room temperature (18C-22C). The sample is then discarded or tasted, but never returned to the fermenter. The likelihood of contamination is too great a risk for the few mils of lost beer! To give you an idea what to expect, for a beer of average strength an O.G. reading would typically be between 1.042-1.058.

    There is a common habit amongst beginner brewers to take several sample readings towards the end of the fermentation to ascertain progress (and from curiosity). This is well and fine if your fermenter is equipped with a tap, but if it means opening the fermenter each time, rather avoid doing so, as it opens the beer to airborne contaminants like wild yeast and bacteria. The less you putz with your beer the better!

    Experienced brewers will usually wait the full 14 days until fermentation is completely finished and only then take the F.G. reading, usually before commencing bottling or kegging. At this stage it’s easy to see ( and taste) whether there has been a problem with the fermentation or not. ( For more information on this see the article”Is my beer ready yet?”).

    Confusion can often arise at this stage, as the gravity reading may seem too high, even though the beer has stopped fermenting. The reason for this is un-fermentable complex sugars and dextrin. These add flavour and body to your beer, and, as the yeast cannot break them down, they remain in solution and cause the reading to be higher. Beers typically finish anywhere from 1.005 to 1.016, with drier beers on the low side, and rich malty ones fairly high. As a general rule the F.G will be 20-25% of the O.G. for example a 1.040 beer will read 1.010 at the end of fermentation.

    If your gravity reading seems higher than expected (according to recipe or experience), let the beer ferment a little longer. Always be cautious, as unfermented beer can over-carbonate bottles or-even worse- cause them to explode!

    Recipes, Target Gravity and Alcohol by Volume

    Where our hydrometer really comes into its own is when working with recipes. Any good recipe will supply the expected O.G. and F.G for the beer. And, with experience it becomes possible to hit these numbers exactly (or be only one or two degrees out at most). Brewers refer to these as ‘target gravities’ and each beer style has its own typical range.

    For example, from the BJCP Style Guidelines here are the average gravities for a Dry Stout: O.G.1.036 to 1050, and F.G. 1.007 to 1.011. Knowing this, if your O.G. was 1.065 it would mean you were brewing a stronger beer than the style usually is – something more like a Foreign Extra Stout in fact (O.G.  1.056-1.075)!. A higher original gravity can often means a higher final gravity, especially with malty beers.

    From your two readings, determining the alcohol content is surprisingly easy. To do so, subtract your F.G. from your O.G. drop the decimal and multiply by 0.129. This will give you the standard Alcohol by Volume percentage.

    E.g.: O.G. 1.058 - F.G. 1.016 = 0.042              42 X 0.129=5.41% ABV

    And there you have it- a quick tour of the hydrometer! To cap off, it’s interesting to note that on many hydrometers there is a choice of calibrations. Apart from S.G. there is often Degrees Plato and sometimes ‘Potential Alcohol’ which is a fairly rough indicator of what percentage to expect. Degrees Plato expresses density as grams of sucrose per hundred grams of liquid- i.e. 10 degrees Plato would mean 10% sucrose by weight to 100% liquid. It’s a more common calibration amongst professionals and crops up only occasionally in homebrewing.

    Prior to the invention of the hydrometer a rather cumbersome method of weighing a barrel of wort and comparing it to the weight of a barrel of water was used. The wort barrel weighed more because of the dissolved sugar in it! Fortunately you will find your hydrometer a much easier option!

    Good Brewing!

    Copyright: Nick Birkby. Used with exclusive permission to Beerlab.

    Written by Info BeerLab — May 06, 2014

    Has my beer stopped fermenting?





    This is a common question that crops up amongst new brewers waiting expectantly on their first or second batch of beer. Fortunately it’s an easy question to answer -and a good opportunity to learn what happens during fermentation as well as a bit about using hydrometers. Read on!


    Firstly it’s a good idea to know what to expect of a fermenting batch of beer. Most of us know that there should be some vigorous bubbling from the airlock (much to the amusement of family members), and a thick head of yeast on top of the beer. This will slow down and eventually subside after a few days, signifying that the time for bottling is soon approaching.

    But what is really going on under that lid?


    To understand what’s really happening in the fermenter we need to understand the basics of what our yeast get up to. These friendly fungi are the ones actually making our beer for us at this point, so their habits and happiness is worth understanding.


    When pitched to the fermenter, the yeast first acclimatise to their new environment and begin to multiply many times over. The yeast use oxygen during this reproductive phase and this is the reason that brewers shake the fermenter vigorously for several minutes to oxygenate the wort before pitching the yeast. The yeast do not yet make any alcohol or carbon dioxide at this early stage -they are far too busy populating the contents of the fermenter! This quiet start is referred to as the lag phase and is where we expectantly wait for 12-24 hours for the yeast population to grow, and then begin on the important (and rowdy) task of producing alcohol!


    Well that’s pretty simple- but you guessed correctly that if the wort is not oxygenated the yeast won’t be able to multiply. This can happen if a brewer forgets to oxygenate or doesn’t shake the fermenter quite enough ( 4-5 minutes is best) . Another important factor is just how much yeast is pitched. A left over half sachet from a few months ago is not going to get the job done! There need to be enough healthy, viable yeast to get off to a strong start populating the wort. Too few simply cannot multiply enough times. So...always pitch a full rehydrated yeast sachet. The lag phase will be short and the yeast happy and plentiful!


    The next phase is the vigorous conversion of sugars to alcohol and carbon dioxide. The yeast have run out of oxygen and now turn to sugar for sustenance. They can survive without oxygen and enter a new phase known as ‘anaerobic’ (without oxygen). The yeast now produce alcohol, flavour compounds called esters and phenols, and work their way through the sugar. The carbon dioxide simultaneously produces a large head of yeasty froth on top of the beer and signifies the peak of fermentation. This busy and productive time is also commonly called ‘primary fermentation’ and is essentially when the magic happens and the young beer is created.


    Once the primary fermentation has begun in earnest there is not too much that can dissuade the yeast from quitting-excepting really cold conditions- below 16C say. As a general rule the cooler temperatures result in slower (and perhaps less energetic) primary fermentation times and warmer faster. Often this stage is over very quickly- two to three days is not uncommon with 4-7 being average. But it’s not quite over yet...


    The last phase of fermentation is where our original question usually arises. Is the beer almost ready? -What is it doing now?-Should I bottle it this weekend? I’m getting thirsty!

    After the initial crescendo of primary fermentation, the beer can look like it has completed its job. This is not at all true though. The young beer has now entered its last important phase known as secondary fermentation. At this point the yeast are still consuming any remaining sugars- though at a much slower rate – and also consuming by-products of the primary phase. The yeast is finishing the job thoroughly and also cleaning up after itself! With the sugar almost gone, the yeast finds and breaks down various other compounds which later affect the finished flavour of the beer. You could see it a gradual finishing or pre- maturation phase.


    Once the yeast has exhausted its supply of food it begins to go dormant. It clumps together and drops to the bottom of the fermenter, eventually leaving the beer clear(a process called flocculation) English brewers refer to this as the beer ’dropping bright’ .Depending on the yeast this can happen quite quickly or sometimes take a while.

    The fermentation is essentially now over, and the beer is beginning to mature. So is my beer ready? Typically, yes, but let’s look at some important time frames and scenarios. Being aware of variables is what is important now...


    Most advice to home brewers suggests a total fermentation time of 12-14 days. This is assuming a ‘textbook brew’ with plenty of healthy yeast and fermentation at a suitable temperature ( 17C-24C ). Generally things work out fine within this timeframe and temperature range. The beer is then bottled, undergoes carbonation from a small secondary fermentation (from added priming sugar) and then has a week or three to mature before drinking.


    Now that you have a general idea of what’s going on under the lid let’s quickly look at how a hydrometer can help us measure the yeast’s progress, and help calculate the alcohol content of our finished beer. A hydrometer is a useful floating measure that will sink lower or float higher depending on how much dissolved sugar is in our beer. Most brewers take a gravity reading just before the yeast is pitched, and then again before bottling. As the yeast consumes the sugar, the hydrometer readings will gradually drop (as the hydrometer floats lower). Generally, taking a reading during fermentation is quite unnecessary if things are progressing normally. Remember, frequently opening your fermenter exposes the contents to bacteria and wild yeast, though if you have a side tap this is a bit less of an issue. There is a good bit of common advice that if one takes a reading for a few consecutive days and gets the same results, the yeast has finished the work –though again this typically this isn’t necessary unless you really aren’t sure.


    Measuring the alcohol content is done by taking (and writing down!) a gravity reading just prior to fermentation called the Original Gravity (shortened to O.G.), and then, at the end of fermentation the Final Gravity (F.G.). The subtracted from the O.G. and multiplied by 0.129 to give the Alcohol by Volume (the same %ABV we see on our commercial beer and wine bottles). Here are three examples of some typical strengths of beer, beginning with an average strength.


    Average: O.G. 1.048     F.G. 1.011.         1.048-1.011=0.037             37 X 0.129=4.77% A.B.V.


    Light :       O.G. 1.034     F.G.1.008           1.034-1.008=0.026             26 X 0.129=3.35% A.B.V.


    Strong :   O.G.1.069       F.G.1.014           1.069-1.014=0.055             55 X 0.129=7.09% A.B.V


    In another post I will take a more detailed look at using a hydrometer, but that’s a useful start for now!


    To round up, let’s quickly look at where a fermentation cycle can go astray, take too long or just seem wrong – and why. By now you now have a pretty clear idea of the fermentation phases happening inside fermenter as well as some of the possible pitfalls. Here’s a set of easy ‘Best case’ versus ‘Concerned! ‘scenarios to help you!


    The lag phase: Best case scenario:

    A full sachet of rehydrated yeast s pitched and begins to ferment (bubbling airlock) after 6-12 hours (or even sooner). The temperature is within target range specified on sachet (or manufacturer’s website)The wort was vigorously shaken and splashed to aerate it thoroughly. A light froth begins to form on the beer.


    The lag phase. Concerned! :

    After 24 hours nothing is happening or there is only very occasional bubbling from the airlock.


    • Check that the airlock is properly secured- often a slight leak in the airlock’s grommet seal stops it from bubbling as the CO2 is escaping around it. 17C to 24C is your ballpark. A quick peak in the fermenter may reveal an actively fermenting beer!
    • Is the fermenter sitting in an icy winter garage or is the temperature really low? Keep the fermenter in a warm enough room. 17C to 24C is your ballpark. Did you aerate enough (or possibly forget)? If not, do so immediately- it should help get things going.
    • Under-pitching(not enough) yeast will also slow things down considerably. Consider pitching more yeast. Slow bubbling does mean something is happening – often it will simply get going properly in another few hours. If you have checked through the variables, grab a beer and don’t worry.


    Primary Fermentation: Best case scenario:

    A rocky head of yeast forms on the beer and the airlock is happily bubbling away. Regular bubbling slows right down after three to six days (sometimes sooner) . A foam line can be visible from the high ‘krausen’ on some fermenters. Remember: warmer temperatures result in faster fermentations than colder.


    Primary fermentation. Concerned!:


    Very slow or sluggish fermentation.

    • Cold temperatures are your main cause for concern here if the other factors like yeast and aeration have been checked. Move the fermenter to a warmer area.
    • Warm temperature and a low gravity beer can lead to very quick fermentations- as short as 2-3 days. Primary fermentation may have already taken place.


    Secondary fermentation. Best case scenario:


    The airlock slows down to a very occasional bubble. The surface of the beer clears with a few light patches of thin foam here and there. Many brewers use the airlock as an indicator at this point-once activity stops completely the beer is done. This works pretty well, just be aware that a very cold spell can also make your yeast go temporarily dormant!

    At this stage the beer begins to clear of yeast, and after a few days the yeast should have formed a thick visible layer at the bottom and the beer cleared. At this time you can bottle within a few days or let it mature for another week or so if you do not have time. Remember; two to three weeks are the best length of time to wait before bottling.


    Secondary fermentation. Concerned! :


    The beer smells ‘off’ or the airlock is persistently bubbling.


    • A bad smell (and there are many kinds!) or a visible growth on top of the beer means that wild yeast and/or bacteria have got in and wreaked havoc. Pay more attention to sanitizing. It’s not common, but it does sometimes happen-quite often more in summer or autumn when there is a lot of wild yeast floating around. A ‘green apple’ smell is normal for young beer, and a light sulphur smell is also known with some yeast strains.
    • A persistent fermentation can mean two things. Most probably the yeast is simply taking longer to get the job done or, less likely, wild yeast and bacteria have taken residence. Most likely it is the strain of yeast that is simply taking a little longer than usual. If in doubt have a sniff in the fermenter. It should smell initially of carbon dioxide followed by a clean beer/hoppy/slight green apple aroma. If in doubt, a gravity reading will help.


    With a little experience and the information here, you will soon always know when your beer is ready. And it’s a very satisfying thing to know too-good luck with your brews!


    This article is copyright and used with exclusive permission to Beerlab. Nick Birkby 2013

    Written by Info BeerLab — September 01, 2013

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