What To Do If My Kombucha Is Brewing Too Slow
My Kombucha Is….. Taking Forever!
Usually kombucha which has gone through a slow process of fermentation has a better flavor to it than faster ferments. Slow fermentations also have the considerable benefit of tending to keep the bacteria and yeasts within the SCOBY in balance, resulting in a consistently healthy SCOBY.
However if your fermentation is taking longer than 4-5 weeks to mature, then something to do with the conditions, SCOBY, ingredients or outside influences is not right. There are a number of factors which could be causing this, but with luck, it shouldn’t take you too long pin point the cause of the problem. You may want to read our guide on how to estimate the perfect brewing time for your Kombucha as well.
I will go through the possible causes, starting with the most common or likely.
What Causes Sluggish Fermentation
Extremely slow or sluggish fermentation can be caused from a number of different factors, or a combination of a few. The important thing is to eliminate what is NOT causing the problem and then focus on could be the possible issues. Here are the different common causes of very slow, or complete lack of fermentation:
Low temperatures are the most common cause of slow fermentation. While slow fermentation is not a bad thing, and as I mentioned above actually produces a better brew, chronically slow, or a complete fermentation stall, is obviously not what one wants.
64 degrees Fahrenheit (18o Celsius) is generally considered the lowest temperature in which a SCOBY can happy grow and produce good ferments. Below this temperature the bacteria sort of go to sleep, and the yeast becomes very subdued, producing nothing much other than alcohol. However the yeasts and bacteria within the SCOBY can adjust to a certain degree. If you see that your SCOBY culture is growing, then great! That means that they are managing with the low temperatures, and you do not need to worry about the fermentation.
Kombucha brewing in cool to cold areas requires more patience, but it is not impossible, and in many cases provides a better quality of brews. Slow fermentation actually increases the amounts of health giving organic acids present within the finished brew, and if you stagger your brewing cycles so that they overlap, or increase the size of the brews and store the bottles carefully (for more on this have look at this How to Prevent Your Kombucha Bottles from Exploding), you can still have kombucha to drink on a daily basis.
There are also many ways to keep your batches at a more conducive temperature for fermentation, such as lights, electric blankets etc. It is even possible to purchase special kombucha heating trays online AFFILIATE LINK?. In some cases even finding an automatically warmer place in your house, such as the back of the fridge, or on top of a warm water aquarium, might be enough. If you are thinking of putting your ferments ontop of the fridge, just check that the opening and closing of the door is not rocking the fridge a lot, as this might disturb new SCOBYs forming. For more information on to how make kombucha and keep your SCOBY happy in colder areas, read Cool Weather SCOBY Care: Brewing Kombucha in Cold Weather.
Too Much Sugar Or Glucose
An overly high amount of sugar in your starter tea can cause the yeasts to ‘fall asleep’. Usually when the yeasts are not as active as they should be, a common cause can be lack of sugar, because without enough sugar, there is too little food for them. However, too much sugar can also have a detrimental effect in that the high level of sugar starts to act as a preservative, effectively stalling the yeast activity.
Starter Or Culture Has Been Refrigerated
If either the starter or SCOBY culture has been refrigerated prior to being put into the brew, this could definitely have a detrimental effect on the ferment. When exposed to very low temperatures, such as in the refrigerator, both the yeasts and the bacteria which make up the SCOBY and also free float in the starter liquid, will go into a state of hibernation.
Trying to make a mature brew from a refrigerated starter or SCOBY will be slow. It might be that only after a few consecutive brews will the bacteria and yeasts have revived sufficiently to start producing regular ferments within the normal time frame.
Too Little Starter
If you are using less than two cups of starter to one gallon of sweat tea base, this could also be causing a problem with regards to the time it takes for the brew to ferment. Starter liquid provides the SCOBY with an acidic environment to starts its process. This is important, as it is the optimum ph level for SCOBY activity. The SCOBY will obviously create its own acidic environment once it starts working, but if the SCOBY is unable to get going initially, then things can stall.
Starter liquid also contains additional free floating yeasts and bacteria which are already active and working away. If you are short on starter, a good option is an extra bottle of store bought kombucha, but it must be unflavored and untreated.
Insufficient Access To Air
Limited access to air is another factor which can cause the SCOBY to be unable to ferment the sweat tea base properly. Oxygen is vital to the fermentation processes that the yeasts and bacteria stimulate.
If the opening of the container which you are using is very narrow, the surface area of the liquid might be too little to expose the SCOBY to enough oxygen. A popular ratio is that the diameter of the surface area should be equal to the depth of the kombucha liquid. Good ferments do not necessarily need this exact relationship, but it is a good spec to keep in mind when selecting brewing containers. If you want more information on kombucha brewing equipment and jars, you can also read Bare Essential Kombucha Equipment Needed and Best Kombucha Equipment.
Another thing which might be limiting the amount of oxygen reaching the kombucha and SCOBY is the covering used to keep dust out of the fermenting vessel. If it is a very thick or dense material then it could be that it is allowing very little air through, and it would be worthwhile to try a lighter material.
Overworked Dying Culture
While given the correct conditions SCOBYs can live and produce kombucha for long periods of time – there are even accounts of SCOBYs stored in sealed jars for years which were revived – they do also get old. While the top layer should still be active, the bottom layers of an older SCOBY might contain dead material. It is a good idea to either split SCOBYs after using them a few times, or merely brew with a new baby which has formed.
Placing the SCOBY into the sweat tea base before it has cooled down fully will severely damage it! This will inevitably result in a brew in which fermentation is not taking place. Be sure to let your tea cool to an ambient temperature in order to not compromise your SCOBY when adding it to the tea.
Contaminants can come in numerous forms, such as chemicals within the water used for the brew, antibacterial soap residue within the brewing container, eroded metal from contact with metal containers or utensils, and or toxic sprays within the air. Think about what your kombucha and SCOBY might have come into contact with recently, and you might be able to locate the source of the problem.
You can reduce the chance of a contaminant affecting your Kombucha by washing your container with hot soapy water, carefully rinsing your container with water, using clean linen for the kombucha ‘lid’, and ensuring your brewing area is CLEAN and clear of potential contaminants (away from any fruit, garbage, dust and such). You’ll also want to make sure you are using the proper brewing container such as GLASS or stainless steel. Using the wrong metal (such as copper or iron) or a non-food grade plastic may cause metals / chemicals to leech into the brew,
Flavored teas can sometimes contain additives which cause damage to the SCOBY. It is not a good idea to use flavoured teas in your sweat tea brew. It is easy to flavour the Kombucha tea after removing the SCOBY, and that way there is no risk of harming the culture. Herbal teas can also pose the risk that some of them contain oils which inhibit the SCOBY. For guidelines on the best tea to use in your brew, have a look at What is the Best Tea For Brewing Kombucha.
Is The SCOBY Still Growing?
If the SCOBY is still growing then it is unlikely that it does not have enough air, that the culture is too old, that it has been inadvertently cooked with hot tea, or been contaminated, whether by flavored tea or chemicals.
If you are still observing growth of the SCOBY, then the very slow fermentation is probably due to (or a combination of) low temperatures, too much sugar, dormant culture (often because of refrigeration) or too little starter.
With a little patience and some trial and error, you should be able to pin point the problem areas. If your SCOBY is not growing at all, then it would probably be a good idea to use one of the babies’ it has produced for your new brew. If you do not have a baby SCOBY to use, and do not have a source from a friend, you could either purchase a new one online, or grow one from any Kombucha you might still have on hand. This can be fairly successful, providing that the Kombucha is unflavored. For instruction on how to do this, have a look at How to Grow a SCOBY from Scratch.