I don’t know of a single person who doesn’t enjoy a bubbly, carbonated beverage. Our culture’s love affair with soda has certainly proven that, but these bubbly, flavorful drinks don’t have to be sugar-laden and bad for you. Carbonated fermented beverages are flat out delicious, refreshing, and the one ferment you can get just about anyone to eat. Whether it’s kombucha, water kefir, ginger beer, or fermented lemonade; there are a few factors that go into making them nose-tingling carbonated.
The Second Fermentation
For ferments utilizing a mother culture such as kombucha or water kefir, it is during the second fermentation that the carbonation happens. During the first fermentation the culture is imparting probiotics, enzymes, and acids to the sugar water and is generally not sealed off from the air. This is then strained from the mother culture and bottled into airtight bottles for the second fermentation.Enough Sugar
The culture then consumes the sugar and produces carbon dioxide – which is how it “carbonates” the drink. In order to produce this gas, the beverage needs enough sugar – either left over after the first fermentation or added – to produce the bubbly fizz we love. Adding a teaspoon of sugar, fruit juice, or slices of fruit can aid in the carbonation process. One more thing to keep in mind, in regards to sugar, is that overdoing the first fermentation makes it difficult to achieve carbonation, even with added sugar during the second fermentation. I hypothesize that this is due to an overstressed culture and a too acidic/alcoholic beverage going into the second fermentation.
Airtight Bottles
The other factor that is critical is to actually trap the carbon dioxide fully. I’ve used canning jars before and this produces some fizz, but it is dependent on how well the lids and rings hold in the gases. If these are bent or mangled in any way, the carbonation is greatly decreased. That is why using Grolsch bottles or bottles left from a purchased beverage that was intended for the purpose of carbonation is important. Safety is also important here as bottles can literally explode if they are not in good shape or if they are allowed to carbonate to an unsafe degree.Time And Tempurature
The final consideration is how long you allow this airtight fermentation to take place and at what temperature. Heat and time are related inversely, that is as the temperature rises less time is needed to produce the fermentation. It is common, therefore, for carbonation to take up to twice as long during cooler parts of the year than warmer parts of the year. So, if your bottles aren’t carbonating enough, consider adding a small amount of sugar, using proper bottling techniques, and giving it the time and temperature that it needs.
