Summer is just around the corner and it’s time to transition from winter to summer brewing habits. For some people, this might be the only time of year it is warm enough for home-brewing. If this is the case, then it’s time to take that scoby hotel out of storage and wake up that hibernating yeast. And if you are already actively brewing, then there will be a few changes you’ll need to implement for summer.
As the yeast consumes the sugars in the kombucha it gives off two bi-products - CO2 (carbonation), and ethyl alcohol. During the winter, your home may be anywhere from 65-75 degrees, if you live in Southern California like I do. This means your first fermentation may last anywhere from 14 - 21 days, and second fermentation will be from 4 - 6 days to increase the carbonation levels.
However, during the summer when temperatures are higher, your yeast will feast at a much quicker rate. Your initial fermentation is shorter lasting 12 -14 days, and your brew may already contain some carbonation without bottle it. For more carbonation, you can bottle your brew for an additional 3-4 days. Yet be careful if you are adding fruits or juices high in sugar during the second fermentation. In a warm environment, the yeast in your brew will be working overtime to convert that sugar to carbon dioxide and alcohol. You should “burp” your bottles daily to release the gas pressure. I recommend doing this while holding a cloth towel over the top of the bottle to prevent an overly carbonated brew-splosion spraying you in the face. You can turn the brew slowly in the bottle but avoid turning the bottle upside-down to mix it; otherwise you will end up with an overflowing science fair volcano the next time you open that bottle.
Hopefully this post has helped you by explaining the subtle differences that occur when brewing kombucha during different seasons.