Even after pasteurising the kombucha / tea brew, we are facing the fermentation in the bottle which is resulting in increase in gas production inside the bottle. we are now in concern w.r.t addition of preservative or should we look on any other alternatives apart from addition of preservative . Please suggest few things that we can control the growth of yeast even after pasteurising .

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    Please edit in a detailed description of your Pasteurization process and equipment. A process temperature profile that works in a commecrial pasteurizer with an efficient heat exchanger would require rather different timing to be effective on filled bottles, for instance.
    – Ecnerwal
    Commented Feb 28 at 21:02

2 Answers 2


You have not actually Pasteurized it.

You have a flaw in your process. Try again.

Check the calibration of your thermal sensors and/or alter the process parameters to apply more heat.

Attempting to Pasteurize it is about as close as you appear to have gotten. If you had succeeded, it wouldn't be fermenting afterwards.

If we're talking a few bottles for home use, refrigeration may slow the process adequately if there's not too much sugar left and you don't mind fizzy. Releasing the pressure may be required if the bottles are weak or there's plenty of food left. If you're doing industrial quantities, you have a grave error and need to get the process parameters properly adjusted.

(I don't do much with kombucha but I have loads of experience with intentionally fizzy beer, cider & and mead. I highly recommend re-using champagne bottles if you want one that will take more than the usual amount of pressure...but you need to avoid making bottle bombs, whatever bottle you are using.)


The whole point of pasteurizing is to kill off the microorganisms within the beverage. If it's still fermenting after the pasteurization, that means the bacteria survived the pasteurization process. So pasteurize it again*, and do it properly this time.

As to why the pasteurization failed, it depends on your actual process, but my first guess would be that you didn't heat it hot enough and/or for long enough.

*: Note that if the bottle is sealed and the continued fermentation added enough additional gas, you might need to break the seal and let some or all of that gas escape. Otherwise, adding heat to an already over-pressurized bottle might cause it to explode.

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