9 Ways You Could Be Exposing Your SCOBY To Mold (and how to prevent it)
While we have a lot of guides on SCOBY care, what to do and what not to do, and how to keep the culture in balance and optimum health, kombucha SCOBY cultures are pretty tough organisms. There are not many things which can go so wrong with a SCOBY where you cannot rectify the issue, or which can cause you to have to throw it out completely.
There is one thing though which usually spells the end, and that is mold. If a SCOBY is contaminated by mold, in most cases the best thing to do is just chuck it out. Usually it is very difficult for mold to take root in the SCOBY culture, as the acidic ph of the brewing kombucha is not the right environment for mold, and therefore it cannot grow there.
However, there are a few things which you might be doing which could be opening your culture up to mold. I will list them below. But first, if you think you might already have mold, but are not sure – as is often the case because SCOBYs can have a variety of phenomena which might give the look of mold – check out The Ultimate Guide to Figuring Out if Your Kombucha SCOBY Has Mold (or NOT).
If your culture has contracted mold and you want to try and rescue it, you can find out how to do so here in What To Do If Your Kombucha Has Mold.
But hopefully this is not the case, and we can go straight on to what to do to ensure that mold never has a chance.
While it is not usually very easy for mold to take hold and infect a SCOBY, due to the acidic ph of kombucha brews, there are some things which can up the chance of mold being able to come into contact with and contaminate a SCOBY culture.
You can significantly reduce any chance for mold to be able to grow on your SCOBY by ensuring that you are not making the following mistakes:
#1 You Don’t Use Enough Starter Liquid
Not using enough starter liquid in your new brew is probably the main culprit of mold invasions in the SCOBY culture. You may have wondered why one is supposed to incorporate starter liquid with each new batch, as surely there are large enough quantities of the bacteria and yeasts within the SCOBY itself to start fermentation, without one needing to add kombucha tea as well? This is correct. The reason one is supposed to add starter liquid, is not to incorporate extra free floating yeasts or bacteria, but rather to keep the ph at a level low enough for the kombucha SCOBY. Kombucha is naturally acidic in ph. The SCOBY turns your sweet tea base more and more acidic the longer fermentation is allowed to take place.
The kombucha SCOBY needs an acidic environment in which to thrive. However, this is not the only reason why one adds starter. Turning the new brew of kombucha slightly acidic from the start also creates an environment in which it is very difficult for mold or foreign bacteria to take hold.
Mold does not do well in an acidic ph. This is the main reason why you must ensure that you are adding enough starter liquid. And be sure not to leave it out! If for whatever reason you do not have any left over kombucha to use for starter liquid, you can either purchase some, or merely use some spirit vinegar. This will turn the ph level of your sweet tea base slightly acidic immediately. If you are substituting vinegar for starter liquid, add half the volume of spirit vinegar that you would with normal starter.
#2 Your Kombucha Starter is Too Weak
You might be saying ‘But hold on, I always use starter liquid!’ There is another factor to consider with regards to starter liquid, and that is – how strong is your starter liquid? Some people like to leave their kombucha to ferment until it is very strong and sour, but others prefer a milder fermentation.
If you are stopping your ferment sooner rather than later, in order to have a sweeter kombucha with less of a tang, then even though you are adding enough starter liquid to your new brews, is possible that the ph is not low enough to make the new batch of sweet tea base acidic. In this situation you can either up the amount of starter liquid which you are using, or add some spirit vinegar. If you are choosing to add spirit vinegar, then follow the half vinegar to starter liquid ratio. If you want to make your brews more potent – as the longer they ferment the higher amounts of organic acids, vitamins and enzymes they contain –then one can also increase the sweetness again and add additional flavourings by doing a second ferment. For a detailed guide on this, have a look at How To Make Second Ferment Kombucha (And Why You Absolutely Should).
#3 Inadequate Hygiene During Brewing Process
Not washing your hands, brewing vessels, and other kombucha making equipment can result in mold taking up residence within your SCOBY. But before you rush off and grab the bleach take note: Do not use antibacterial soap to clean your kombucha items.
Antibacterial soap kills bacteria, and the kombucha SCOBY culture is made up in part by friendly bacteria. These bacteria will suffer if they come into contact with any residual antibacterial soap left on your hands or brewing equipment. To thoroughly sterilize your vessels and other items, you can use ordinary soap, hot water and spirit vinegar. If you are still worried about soap residue, just the hot water and vinegar is also adequate. Just be thorough. You can soak your utensils in boiling water to sterilize them, and use vinegar for the glass brewing vessels. Putting boiling water into glass containers is a bit dangerous, as this can cause the glass to crack and break.
#4 There Are Plants Near Your Kombucha
Close proximity to plants can also play a role in mold infestation, or increase the chances of this happening. If you are using ample starter liquid, which is strong enough, then plants close to your brew should not be a big risk, but it can be a source of mold spores.
#5 You Are Brewing ‘Buch’ Too Close to the Trash
Mold often forms on trash. If you brew your kombucha anywhere near the trash, mold spores may migrate to your Kombucha brew and infest it. So do not keep your kombucha anywhere near the trash. If you have garbage in the kitchen, make sure it’s under the counter and in a sealed container. If you keep a garbage can with trash (especially food trash like fruit, bruid, old dinners, etc) near where you brew kombucha, you are asking for a mold infestation in your kombucha.
#6 You are Brewing in Cold Temperatures
Somehow, one would think that warm temperatures would encourage mold growth more than cold, but with kombucha brewing, in cool temperatures the yeasts do not acidify the brew as quickly as in warmer temperatures, because the whole fermentation process is slower. This gives any airborne mold spores an opportunity early on in the fermentation to jump in.
#7 Someone’s Smoking Near the Kombucha
Do you or someone else smoke in the same room in which your kombucha is brewing? Exposure to tobacco smoke can make the kombucha SCOBY culture vulnerable to mold invasions. Tobacco smoke and the chemicals it contains can weaken a SCOBY, to the point where it is not fermenting properly, and is vulnerable to outside mold spores or foreign bacteria.
Other than smoke, chemicals in the air (for example aerosol sprays or insect repellent) or water can also negatively impact the SCOBY culture to the point that mold and or foreign batter can take hold.
#8 Your SCOBY has Health Issues
This is another one. If your SCOBY is dead or dying, your Kombucha won’t ferment which means mold WILL eventually grow on top of the tea. We recommend you avoid buying dehydrated SCOBYs that are sold on various online shops. These SCOBYs are often unhealthy (you are DRYING out a living organism then re-hydrating it weeks or months later) and may NOT come back to life when you try to re-activate them. Even if you reactivate a dehydrated SCOBY, the culture may be so damaged by the process that it can’t properly ferment the tea which allows mold to grow.
#9 High Humidity
High levels of humidity can also cause a SCOBY to be susceptible to mold. Of course, one can’t just turn the humidity of the area in which you live up or down, but if you do live in a humid climate, be sure to follow the above guidelines to make certain that your SCOBY is strong, and in an acidic solution which will make it very difficult for mold grow. And if you are storing your brewing vessels in the bathroom, or close to the kettle where it is in regular contact with steam – it might be a good idea to move them.
Final Caution On Moldy Matters
The most important thing to keep in mind when it comes to matters of mold is that mold cannot grow in acidic environments. This means that if all is going well with your kombucha brewing, then mold will not be a problem. If however the initial vessel of liquid and SCOBY is not acidic enough, the SCOBY is compromised and not carrying out fermentation properly, is being harmed by soap residue, or bombarded by harmful substances, then mold will be given a chance to take hold.
One other consideration is that mold is thought to be able to live within a SCOBY culture for some time without being visible, and once conditions reach a point where it can grow, then visible signs of it can appear. This does not mean that there is a big possibility that you have mold in your SCOBY without ever knowing it, but it does mean that one should always try to ensure that it cannot get into the culture in the first place
This is one of the reasons why it is not really advisable to try and rescue or clean a culture which has been contaminated by mold, as it can remain in the cellulose tissue only to resurface in successive brews.