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Has my SCOBY gone bad? Correct Kombucha Brewing Temperatures and more

Has my SCOBY gone bad? Correct Kombucha Brewing Temperatures and more


For many first time brewers, receiving a warm SCOBY culture in the mail on a hot summers day can be disconcerting. “Shouldn’t live kombucha cultures be kept cold? How long has this been in the mail for? Is this SCOBY safe to brew with?”


These understandable concerns can cause undue worry and frustration. You’ve patiently waited for your package to arrive, and are eager to start brewing – or you just got back from vacation to find out your kit has been sitting on the porch for days! What a shame it would be if your baby SCOBY had frittered away in your absence.  

Except in rare case of extreme weather conditions, SCOBYs will be totally OK to brew with if they have been out for a bit.

The combination of the acidic nature of the nutritional liquid the SCOBY sits in and the bag’s airtight seal keeps mold and other ‘buch invaders at bay. The bigger issue at hand, as foreshadowed above, is extremely high or low temperatures that will either cook the culture (85º through 90ºF) or start to destroy its complex cell structure if it starts to freeze. 

Remember! This is a living culture, and is not unlike humans in this way. Too hot and we sizzle up, too cold and the damage can be irreversible.

Mid-70º’s to 80º's though, is the ticket. Give us a warm day and a nice breeze (SCOBYs love breezes, it keeps the flies away) and next thing you know we are all getting stuff done during the day and staying up all night. Just like the SCOBY.   BETTER WARMER THAN COOLER: Kombucha is a stable beverage due to it's acidic nature, and its acidity is dependent on the plethora of pro-biotic bacteria having a warm environment to create acids like Glucaric and Gluconic acid, Acetic acid, Caprylic and Butyric acid. If your brew is below 70ºF, you run the risk of not maintaining a stable pH environment and expose your brew to mold!  


What the fridge is great for:

Keeping your culture cold (~40ºF) when you are taking a brewers break.
  • Simply set your culture in a cup (depending on how big it is, you may want to add more or trim your SCOBY) of kombucha in a glass or ceramic bowl, cover it, and set it to the back of your fridge.
  • There it will hibernate, as its metabolic rate slows into a state of low activity.
  • You can keep it there for a couple months at a time, but it's best to give it a quick refresher every couple of weeks with a little jolt of fresh tea and sugar.
Bottle Conditioning! You can also vintage your kombucha in the fridge for great lengths of time - the flavor can be as complex and delicious as great wine. Just remember:
  •  Use a bottle / cap with a good seal
  •  Label what your brew is, and what ingredients you used
  • Date it
  • Resist temptation! if you open it early on, you will loose some excellent fizz. Save it until you are ready to drink most of it.
  • Enjoy!

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  • Eric
Comments 2
  • Chris

    Hi Michelle, be sure it’s not normal SCOBY growth – mold is always dry and fuzzy. Check out this blog about mold, as well as this blog. Happy brewing!

  • Michelle Sanchez
    Michelle Sanchez

    I’m new to making my 1st batch of Kombucha. I was given the mother and used Green/Black tea and set my scoby in with some bucha from the last set tea it was in before. It has been a little over a week and I went to check and the top is molded over. I’m not sure what to do. I hear to throw it away…. but Do I throw away everything? I notice a couple new scoby’s underneath the moldy top layer. HELP Please I would like to be successful at this.

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