Its heartbreaking when you remove the bandanna to peek in on the fermentation process just to discover patches of white dust or green fuzz coating your precious scoby-baby.
"What did I do wrong?" "How could this have happened?" and "How do I prevent this from ever happening again?" are questions I've asked myself, and have been asked by clients. In this post, you will learn some causes for mold, some tips for avoiding it, and how you can prepare yourself for when it happens.
Although initially you might feel sad, or even angry when mold occurs, it is important to view the bright side of things. This mold was a visible sign that something sinister was lurking in your kombucha that could have had the potential to make you very sick if you drank it. So if mold happens, be grateful it was a sign that your brew was not up to high health standards and needed to be discarded.
So What Causes Mold?
Moldy-Scoby Syndrome is caused by 3 main factors: cold temperatures, not enough starter liquid, or environmental contamination.
Brewing is best done at a temperature of 75-85F (24-29C). Remember, if you put your scoby in the fridge, it will go into suspended animation until it warms up again. Essentially that is what happens if your kitchen is too cold in the winter, your scoby falls asleep and it cannot acidify quick enough to prevent mold from developing.
If you do not have enough starter liquid this will also impact your scoby's ability to acidify quick enough to keep airborne mold spores at bay. When you add your starter liquid, you are adding at least 1 cup of highly acidic kombucha to jump start the process and introduce an initial level of acid to protect from mold growth.
Being cautious that all of your materials are sterilized before using them can make the difference between a happy scoby, and a scoby with it's gallon of tea being poured down the drain. I use a sterilizing liquid common in brewing beer to clean all of my instruments before I brew. I'm afraid boiling your water and hoping it will kill off all the germs just doesn't cut it.
What Do I Do Now?
I'm sorry to say this but, 'Yes, you do need to throw it all out.' Believe me, I've tried to pull off the affected new scoby leaving the original scoby and kombucha to grow a new healthy scoby - it doesn't work. Remember, mold is a sign that something lurks beneath the surface so simply removing the surface problem doesn't actually resolve the problem.
You need to start fresh with a new scoby and starter liquid. You cannot use contaminated kombucha to start your new batch or you'll be repeating this cycle of scoby sickness. One way to prepare for disaster is to keep a scoby hotel. Add layers to your hotel as new healthy scobys form to keep as a backup copy of your original. Be sure to always keep at least one cup of komubucha in reserve so you will have enough starter liquid to begin again.
Wash and sanitize everything before starting again. Reevaluate the location your brew is sitting in; is it by the fridge or window where it might be colder? And don't forget to keep your brew covered with a clean bandanna to keep dust, flies, and hair from coming into contact with your scoby. Exchange this bandanna with a temporary paper towel as you wash the bandanna between brewing batches.
Lastly, if you are worried about the acidity level, adding more starter liquid wont hurt. In the winter I also like to peek in on my scoby every few days and douse it with a spoonful of the komubucha from beneath so that I am sure the surface of the scoby has enough acid on it to protect it during cooler brewing periods.
Its a sad day when a scoby dies because of mold contamination. I hope you find this post helpful in preparing for and preventing mold from occurring in your komubcha and that future scobys are saved by the knowledge you have gained here today.