Kombucha Brewing: Carbonation
Getting that Carbonation Right
Getting the right amount of carbonation can be a little challenging in kombucha. I feel like it’s not just about putting some extra sugars into the bottle for your secondary fermentation. There are a few factors that you need to take into account to get the secondary fermentation that is right for you and your kombucha. Let me explain.
How’s Your SCOBY Doing?
First of all, I found the condition my SCOBY is in seems to affect the carbonation quite a bit. When I started to brew my kombucha again after leaving it alone for about half a year, the SCOBY was not as active, and took a long time to get its fermentation started. Obviously having a healthy starter liquid and healthy SCOBY is key to good kombucha, and when I first started to bottle condition (secondary fermentation) I hardly got any carbonation. The kombucha I was originally bottling was pretty flat and didn't have that tingling feeling you get when you drink naturally carbonated drinks. The reason why I bring this up is because now even without bottle conditioning, I actually already get carbonation in my kombucha, yeah its great. Even without having a completely closed off environment, I have bubbles floating under the SCOBY, sticking to the side of my brewing jars, and you can hear the carbonation popping when I pour into a glass for daily tasting. I' have read that the dark colored scum looking parts of your SCOBY is the yeast that creates the CO2, but I find that not true for my brew. My black tea kombucha has none of that on the SCOBY and its already slightly carbonated before bottle conditioning. I feel like it’s more about the healthy of your SCOBY, your starter liquid, and a stable brewing temperature and repetition of brews.
What Sugars to use in secondary fermentation
and how much
So next part of secondary fermentation is what sugars you want to add in your bottle to give that extra food your kombucha needs to make more CO2. To be honest I think you can use whatever juice, fruit, sugars you can find, but it’s more about finding what works for you. In my experience with my SOCBY I find that fresh juice and unfiltered juices work the best for me. I’ve tried using filtered grape juice like welch’s, but I never seem to get that much carbonation (This might also be related to the amount I used).
I also tried simply macerating fresh beets and adding that to my kombucha, and that just exploded when I tried opening it . Recently I have been using unfiltered apple juice and that seems to hit the right area between juice and macerated fruits.
Recently I took a liking of using unfiltered apple juice for my secondary fermentation for the mouthfeel and how it had a similar flavor profile to the kombucha I was brewing. For my 500ml bottle I would first use 120ml-130ml of apple juice but I got absolutely no carbonation. So I decided to up the amount to 160ml and bam, I guess that was the right amount for the kombucha to get kicked into carbonation mode. After I changed the amount, I get good and consistent carbonation from my kombucha.
The “right” amount of carbonation
So you got your carbonation down but is that it? For me I like to think about what I want from my kombucha to decide the carbonation I want. I’ve seen kombucha videos on Youtube where they just get this crazy amount of carbonation where it is exploding from the bottle. That’s one way of doing it, but I personally don’t really want that because you’re losing so much yield from you kombucha when all of that foam is uncontrollably coming out of the bottle. Especially with the hops kombucha I make, I already loose some kombucha from it being absorbed into the hops. What I look for is a nice sound of gas escaping the bottle, and gentle bubbles rising up to the top but not foaming. When you drink my carbonated hops kombucha it should just gently tickle the inside of your mouth. For my other two kombucha I don’t even bottle condition it, I just let it refrigerate and essentially “lager” in beer terms. I actually don’t mind adding seltzer water to my kombucha because it dilutes it and I can have it in a larger thermos or change the flavor depending on my mood or situation. If you have good flavors in your kombucha the seltzer should lift it and just make it lighter. That’s why I make my kombucha on the sweeter side, rather than sour and dry.
So in terms of carbonation here is what I recommend:
Healthy SCOBY and fresh kombucha
Know what flavor profile you want with your sugar addition
Realize that big carbonation isn’t everything
