During primary fermentation, the yeast in your SCOBY (Symbiotic Culture of Bacteria and Yeast) devours all the sugar in the tea which produces carbonation. However, because your kombucha jar allows for open exchange of gasses, most of that carbonation escapes into the open air.
Kombucha Carbonation:
If you’re craving Kombucha for its fizz as well as its flavor, a second fermentation is key.
1. First remove the SCOBY, along with some of the remaining liquid.
2. Transfer your booch to a glass bottle. If your fermentation vessel has a spigot fill your kombucha bottles from there. To most accurately gauge the carbonation make sure you fill one plastic bottle with the same amount.
3. Be sure to leave about one inch of headroom in the bottles and then let them ferment at room temp for a week or two. During this time squeeze the plastic bottle. If the bottle becomes firm it’s time to refrigerate your kombucha. Note: There is the possibility for your kombucha to create excess pressure on the bottle. Be sure to release this pressure by opening the bottle every few days.
When to Bottle Kombucha
Timing is critical. If you bottle too soon, when your Kombucha is sweetest, the yeast will keep going crazy on sugar and you may have some over-carbed bottle rockets on your hands. If you wait too long, when your Kombucha turns sour, the yeast will have consumed all of the sugars and there will be nothing left to feed them once bottled.
What you’re aiming for is a nice balance of sweet and sour – the holy grail of booch brewing. It may take you a couple of batches to figure out, but take good notes and you’ll get there.