A few points before you begin:
Do you need to sanitize your barrel before you start? No. There’s a small risk for contamination if the conditions aren’t quite right. But if you use enough starter culture (follow your recipe or mix 10 L of starter culture with 10 L of a tea/sugar mix in a 20 L barrel), the kombucha’s low pH and organic acids should make for a naturally antimicrobial environment.
If you do see fuzzy mould spots growing inside your barrel, something’s gone wrong. Dump the batch and sanitize the barrel. Try again.
Should you use a big barrel to make a small batch? No, you need to fill your barrel (almost) to the top, otherwise mould can grow above the liquid. So consider your barrel or batch size carefully – don’t use a 20 L barrel to make 10 L of kombucha, either use a smaller barrel or double your batch.
And how long will it take? Even if your SCOBY (more on that later) is ready to go, your batch could potentially take for 2-4 weeks, depending on your flavour preferences.
So let’s get started!
Step 1. Prep your SCOBY and starter
What’s a SCOBY? The jelly blob used to make kombucha is technically known as a zoolgeal mat, but it’s more commonly known as “symbiotic culture of bacteria and yeast.”
You can buy ready-made SCOBY or a dehydrated version. But if you want to make your own, here’s how you do it:
- black tea (black tea yields better results – you can experiment with different varieties later)
- 1-2 tablespoons granulated sugar
- 1 cup unflavoured kombucha (any store-bought brand will do)
- 2 L glass jar, cheesecloth and a rubber band
- Make 1 cup of black tea and while it’s still hot, add the sugar to dissolve it. Let it cool down to room temperature.
- Pour into your jar then add the kombucha, sediment and all.
- Cover with a few layers of cheesecloth and secure with the rubber band. Place your jar in a dark place, away from sunlight, and where it won’t be disturbed. Maintain it at room temperature.
- Your mix will gradually bubble (it lives…) then a clear film will form on the surface. After 2-4 weeks, you should find a ½ cm (1/4”)-thick, yellow-brown, jelly-like SCOBY has formed. Resist the urge to move it around in the jar, let it do its thing. If it hasn’t formed, something went wrong—toss out and try again.
- Now you have your starter culture and if you take care of it, it could last you years. Just don’t take the SCOBY out until you’re ready to start your first batch. And once you do, toss out the original tea that created your SCOBY, it’s too vinegary to use as a starter.
Step 2. Kombucha, baby!
Grab a cured 5 L barrel and prep your ingredients.
- 4 L clean water
- 1 cup white sugar (sugar alternatives like agave syrup might harm your SCOBY)
- 12 bags of tea (black, white, oolong, green— but no decaf)
- 2 cups unflavoured starter (either store-bought kombucha or from a previous batch)
- Boil the water, remove from heat and add the sugar while it’s still hot.
- Add your tea and steep until your mix has cooled to room temperature—you don’t like taking scalding hot baths and neither does your SCOBY, it will kill it.
- Using your doctor-level clean hands (seriously, clean them as best as you can), gently remove your SCOBY and place it on a plate.
- Pour your sweetened tea mix into the barrel, then add your starter. Your barrel should be filled nearly to the top.
- Gently add the SCOBY then cover your barrel (either with the cover or with layers of cheesecloth secured in place).
- Leave your barrel undisturbed in a dark, warm (20 C temperature) room for 10-14 days. You’ll notice the SCOBY will want to latch onto the sides of the barrel. No harm done, just pull it away from the sides.
- Start drawing a bit of the tea to taste it. The warmer the room (or if your SCOBY is super active), the faster the fermentation. The longer your ferment it, the lower the sugar and caffeine content so your drink won’t be as sweet. Keep it going to maximize the flavours and beneficial acids, but if you leave it too long, it won’t be tasty. So sample away until your mix has the perfect sweet-sour flavour.
Consider saving at least 2 cups of this batch to use as a starter for your next one.
Step 3. Flavour it
If you want to flavour your kombucha (it’s an optional step), you have to add it outside of the barrel. If you add it directly to your barrel, you’ll be impacting the flavours of all future batches or even creating an ideal environment for mould.
Here are a few possible add-ins to inspire you:
- slices of orange
- mint candy
- candied ginger
- mashed fruit or juice (about 1-2 tablespoons for every cup of kombucha)
- honey (1-2 teaspoons for every cup)
Strain your kombucha into a glass container or individual bottles, but leave a bit of room at the top to add your flavouring. Seal tightly — just watch that the pressure doesn’t build up to the point of making your bottle explode. Let it all ferment in the dark and at room temperature for up to 10 days. You can then strain or leave your flavouring in, but place your kombucha in the fridge to slow down the carbonation process.