Kombucha 101

Leslie Gray. Owner, operator and course instructor for Fermentation Station.

I would like to think of myself as an exploratory brewer. I’ve brewed almost every style of beer, wines, mead, cider, and country beverages using a variety of different fruits, vegetables, and spices. One thing I have never thought about really was the world outside of alcoholic beverages. Recently, I had the pleasure of attending a course put on by the very knowledgable Leslie Gray of Fermentation Station, a small kombucha company in Yellowknife, NT, with big flavours and a passion to pass on her knowledge and SCOBY. The course she put on helped open my eyes to a whole new world of fermented magic! 

Kombucha, for people who have never heard about it, is essentially fermented black or green tea with some form of sugar. It is fermented by a thick membrane known as a SCOBY (Symbiotic Culture Of Bacteria and Yeast). It is unknown exactly where or when kombucha was invented. Wikipedia tells us that it can be be anywhere from 400 to 2000 years old, as there is some confusion that comes from the translation for the word “tea” from Russian to Japanese to English, and the confusion between a few different mushroom teas. Ancient Japanese believed that kombucha had magical powers and contained the secret of youth, and in modern times, kombucha is touted to have probiotic powers which is great for gut health. 

SCOBY layers

The SCOBY itself is like an apartment building for a bunch of different tenants that all bring something different to their community. Here are some of the usual suspects that we as homebrewers are used to dealing with:

Saccharomyces class of yeasts
We have all heard of the favourite of this yeast genus—cerevisiae, which is the main player in beer production. But there are a number of other yeast species that belong to this group as well which are present in kombucha like Saccharomyces ludwigii, Saccharomycodes apiculatus, Schizosaccharomyces pombe, and Zygosaccharomyes.

Brettanomyces is another familiar yeast strain, that is also commonly found in kombucha and produces alcohol or acetic acid.

Lactobacillus and Pediococcus are both bacterias that produce lactic acid and slime, with the difference being Lactobacillus is a type of aerobic bacteria, and Pediococcus is a type of anaerobic bacteria. Both are sometimes, but not always, found in kombucha.

And a couple new names… 

Acetobacter is a main player in the fermentation of kombucha. It is an aerobic (requiring oxygen) bacteria strain that produces acetic acid and gluconic acid. Acetobacter strains are what builds the apartment building that is the kombucha SCOBY.

Gluconacetobacterkombuchae is an anaerobic bacteria that is unique to kombucha. It feeds on nitrogen that is found in tea (hence the reason it is made with tea specifically) and produces acetic acid and gluconic acid, as well as kicking in on building the SCOBY.

Zygosaccharomyceskombuchaensis is a yeast strain that is unique to kombucha. It produces alcohol and carbonation as well as contributing to the apartment building.

Let’s get into the process. The brewing process of the kombucha is a pretty basic, especially if you’re an all-grain brewer. The following is the guidelines I got from Leslie:

The different steps of brewing

Step 1: 
Fill a large pot with 2800 ml of water. If the water is from a municipal supply, try leaving it uncovered overnight to off gas any chlorine added to the water. Bring to a boil. 

Step 2: 
Add one cup of white sugar (or your choice of fermentable) and stir it into the pot until it is fully dissolved. 

Step 3:
At this point, add your favourite tea—4 black tea bags or 3 green tea bags. (Note: Loose tea can be used but there is a lot higher chances of mold and other fun things in it so be warned.) The tea can be steeped for 8-10 minutes and then removed, or as Leslie likes it, left steeping while it cools.

Step 4: 
Cool the beverage in a fridge (or sub arctic climate) until it is in the range of 15-25°C. Add this mixture to your kombucha and fermenter. Any glass jar or jug should work as the fermentor. The SCOBY likes oxygen, so whatever you do use try to make sure it has a large surface area and no air lock. Just a coffee filter over top to keep any debris and bugs out will suffice. Leave it in a dark cabinet somewhere that gets open frequently to promote air movement.

The primary steps to brewing kombucha

Step 5: 
Ferment the beverage for about 5-28 days in primary fermentation. The usual fermentation timeline is 7-10 days, but depending on how much of that tangy kombucha flavour you want, you can leave it fermenting for longer. Leslie’s recommendation is 10 days for that perfect balance, and from tasting the few different samples along the fermentation timeline, I would have to agree. 

The final product in the fermentor

Step 6: 
Decant the beverage out of the fermenter and into a pitcher or a pressure vessel. The trick is to keep a small amount of kombucha in the jar to keep the SCOBY nice and happy and ready for your next batch to begin. 

Kombucha can be bottled in any kind of bottle, but swing top is king.

Step 7: 
You’re done! Well not really but you can be. Original kombucha was and is enjoyed by many just like this. It has a beautiful sweet tea flavour that is noticeably tangy, with a slight carbonic bite from the fermentation process.

Step 8 (optional):
This were your personal style and creativity can strive! The secondary is traditionaly always done in bottles to create the beautiful bubbles that add that next level to kombucha that I personally thrive for. Unlike with beer, you do not add any extra sugar at this point. There should be enough residual sugar to get you to the promised world of around 2 volumes of CO2. If you add other fermentable though expect your CO2 numbers to rise, along with the probability for bottle bombs! 

Leslie’s different mixes include ginger cranberry, pumpkin spice, peach, and mulberry.

Leslie suggests using dry fruits to the secondary. Dry fruits possess a lot of flavour for a small volume and keep the sugar levels down. Her one advice—less is more! Flavours can develop a lot greater than you think. The flavour of kombucha is often milder, so it is not hard to go over the deep end and lose some of those beautiful flavours your buddies at the “SCOBY Heights” made for you.

The expense to start this division of your brewing empire is very minimal. The main expense will pretty much be you getting your SCOBY. White Labs sells WLP6000 that will contain enough bacteria and yeast to inoculate one gallon of kombucha. If you want to stay local to Canada, you can check out www.culturemother.ca. If you have a friend who also brews kombucha, you can actually separate the SCOBY without any serious impact on it. If you are unable to pull it apart, you can cut it but beware of the type of knife you use because the SCOBY actually can die from contact with metal. 

I must say I have really enjoyed learning about the kombucha drink and having something else I can make and enjoy with my family. The fact that it is non-alcoholic is a real treat for my kids as they can help me make it, and then enjoy some of it as well! I hope you all have found some inspiration and knowledge to start your own kombucha brew! 

Keep the Boil Rollin’

Shawn Paul Brennan is the Northern regional rep and is a born and raised Northerner from Yellowknife, NWT. He started homebrewing in 2014 with very basic extract kits, then moving to brew in a bag, and on to a 3 vessel electric brewery setup. He also brew ciders, meads, and a variety of different kinds of wines. Contact him at shawn@canadahomebrews.ca.

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