A few hours out of refrigeration isn’t going to ruin your how long can kombucha be left unrefrigerated , but if you leave it out too long, it will start fermenting again and change the flavour. This happens because the yeast and bacteria continue to convert any remaining sugar into alcohol and carbon dioxide, which can cause off-flavors. Refrigeration halts the fermentation process and stops it from creating vinegar, so if you refrigerate your kombucha before opening, it should be safe to drink and will last longer.

The main reason that kombucha has to be refrigerated before opening is to preserve the bacteria and yeast cultures. The kombucha culture is live and can only survive at temperatures above 68F, so it needs to be kept in a dark, oxygen rich environment to stay alive. Refrigerating kombucha keeps it in the dark and protects it from harmful bacteria that can make you sick.

On the Counter: The Science and Safety of Keeping Kombucha Unrefrigerated

While kombucha can last for a few weeks in the fridge, it’s best to consume it within a week of opening to get the most flavor out of it. It’s also important to store the kombucha in an airtight glass bottle with a rubber seal, as this helps keep it fresh and prevents any unwanted bacterial growth.

If you leave kombucha out of the fridge for too long, it will begin to taste sour and may even turn into vinegar. If you notice a vinegary smell when you open your kombucha, it is likely that it has gone bad and should be thrown out. It’s very rare for kombucha to go bad and become unsafe to drink, but if it tastes really sour or vinegary, it is best to throw it away.