How to Increase Bacteria Populations in Kombucha
Do you need to increase the bacterial population in your Kombucha? In this post we take a look at the main methods you can use to stimulate and encourage the kombucha bacteria.
The microbial populations in kombucha consist of a balance between yeasts and bacteria. The two populations work together to carry out the fermentation process. Maintaining the balance between these two communities is vital to the health of your ferment.
Kombucha and SCOBYs which have balanced populations of yeasts and bacteria tend to produce better kombucha and ferments which yield more consistent results.
While the yeasts and bacteria support and need each other to survive – they are also in competition with each other. Depending on which conditions are present, one or the other can gain dominance and throw out the health of the SCOBY.
While there are cases where the yeast populations suffer, it is most common for the yeasts to gain the upper hand. The bacteria and yeast populations have differing conditions which they prefer. If conditions favor the yeasts, then they will multiply, and suppress the already compromised bacteria.
If this is the case with your ferment, then you can take steps to control the yeasts and encourage the bacterial populations.
4 Ways to Increase Bacterial Populations
The aim of the game when encouraging the bacteria is to create conditions which favor them, and suppress the yeasts. You can also reduce the yeasts manually, to give the bacteria more breathing space.
# 1 Lowering the Temperature to Encourage the Bacteria
The bacteria in kombucha prefer a lower band of temperatures than the yeasts. Brewing in hot weather is often the cause of of a yeast overgrowth, and with that reduced bacterial populations.
Kombucha can be brewed within a temperature range of 69-84 degrees Fahrenheit. The yeasts can start to get over stimulated at the upper end of this range. The bacteria do best at the lower end. An ideal brewing temperature for kombucha is 77 degrees Fahrenheit.
If you are brewing above 44 degrees Fahrenheit, then it is likely that this is causing your yeasts to go into overdrive, and the bacteria to suffer. The best way to get things back into balance is to try to lower the brewing temperature of your kombucha.
How to Lower the Temperature of Your Ferment
When it comes to lowering the brewing temperature, you can either try and find a naturally cooler brewing spot – or use artificial means to lower the temperature for your kombucha.
Finding a Naturally Cooler Brewing Spot
If your kombucha is brewing in a sunny warm room, you might be able to lower the temperature enough merely by moving it to a colder room. Setting the brewing containers on top of cold retaining surfaces such as stone, cement or tiles can also drop the temperature of the brewing kombucha slightly. Just make sure that the new spot is clean, well ventilated, and not in close proximity to plants, bugs or cigarette smoke.
Artificially Cooling Your Kombucha
If the temperatures are too high for simply moving your kombucha to a cooler spot in the house to be enough – then you might need to cool it down ‘artificially’.
While refrigerators do not have high enough settings to brew kombucha at – there is a homemade hack you can implement to change this. If you install a temperature regulator in a refrigerator or deep freeze, this will modulate the compressor cycles to keep the temperature within at you desired setting.
This is a good option to consider if you are keen on brewing kombucha, and live in a climate where the temperatures are continually very high. The additional refrigerator, even if it is a bar fridge, is an outlay as well as the regulator. However once you have it set up, then it can save a lot of brewing hassles related to making kombucha in very high temps.
Cooler / Ice Box Storage
This method is more labor intensive than the refrigerator method – but must less costly. All you need is a cooler / ice box to fit all of your kombucha into, and some ice packs. If you do not have any ice packs, you can also use plastic bottles filled with water. Simply freeze the packs / bottles, and pack them into your ice box leaving a space for your brewing vessels. Place the kombucha into the ice box, taking care not to let the ice packs touch the sides of the vessels. Cover with the lid, leaving a small gap for ventilation. Once the ice packs have defrosted, swop them out for a second set, and refreeze. Continue until seasonal temperatures have dropped.
You can monitor the temperature in your box with a thermometer. If the temperature drops a bit low, use a few less ice packs. If it is still too high, you might need to increase the number of ice packs.
For additional info on regulating the temperature of your kombucha in hot weather, you can also check out this post How To Brew Kombucha In (Very) High Temperatures.
# 2 Use Weak Tea
Strong black tea contains a certain quantity of sterols. The kombucha yeasts use sterols to reproduce. If deprived of sterols, they will manufacture their own. This will slow them down a little and give the bacteria a chance to get on their feet.
How to Make Weak Tea
When making your kombucha tea – use no more than 8 tea bags per gallon. This is equivalent to 8 teaspoons of loose tea. You can even decrease to seven tea bags / spoonfuls. Steep the tea in your boiled water for a maximum of 4 minutes and then remove the teabags or tea infuser.
# 3 Remove Some of the Yeasts
Once you have done all you can to give the bacteria the conditions that they like, you can also do a couple of things to reduce the already overgrown yeasts. The yeasts are easily recognizable and easily removed. They take the form of long brown strings which either float free or are attached to the SCOBY itself. Any sediment which is suspended, or has collected at the bottom of your brewing vessels is also mostly made up of fine yeast particles.
How to Remove Yeasts
The main ways to manually remove yeasts is to strain them out and wash them off of the SCOBY.
Straining Kombucha to Remove Yeasts
Straining kombucha is easy to do, you just need to assemble a few items, and then you can strain away. You will need a wide meshed cloth, and either a sieve or a funnel to line with the cloth. Then pour the kombucha through this. The free floating yeasts will be caught in the cloth. If you only have a small amount of kombucha to strain – and a pour over coffee maker – you can also use a coffee filter and with the coffee maker and strain the kombucha through there.
For more info on straining kombucha, have a look at these two posts How to Filter Your Kombucha to Remove Yeasty Stuff and How to Remove Particulate from Kombucha.
Washing the SCOBY
SCOBY washing is surrounded by a little bit of controversy! Often, new brewers are motivated to severely wash their SCOBY before each new brew under the tap. This can be detrimental, especially if your yeast population has not become strong yet. The washing strips away all developing yeast strings, and ‘unbalances’ the SCOBY, in the direction of the bacteria in this case.
However, if you are suffering under severe build up of yeasts, then removing some of these from your SCOBY before a new brew can be a good idea.
Simply rinse the culture gently in some filtered water or rainwater. Do not use chlorinated water, as the chlorine can be harmful to the culture. It is antibacterial remember, and in the SCOBY we need the bacteria. : )
# 4 Use Starter Liquid With Fewer Free Floating Yeasts
If your kombucha has a lot of yeast activity and the bacteria are taking strain – then ten to one the kombucha you use as starter liquid will also contain quite a lot of free floating yeasts. Adding these into each new ferment will only act to slow down the process of getting the yeasts and bacteria back into balance.
Take Starter Liquid From the Top
Fortunately, most free floating yeast particles tend to collect at the bottom of kombucha and build up there. If you avoid this sediment rich section at the bottom, and only take starter liquid from close to the surface – then you will introduce fewer yeasts back into each new ferment.
You can either gently pour out this top liquid, or carefully scoop it with a cup or small jug. Be careful not to move the container that the starter liquid is in too much beforehand. This can cause the sediment to be disturbed and rise in the starter liquid.
As mentioned in the beginning of the post, maintaining the balance between yeasts and the bacteria within your kombucha is the key to having continuously successful and hassle free ferments. At first it might seem like a lot to keep track of, but once you get the hang of monitoring your SCOBY and ferment everything gets a lot simpler.
When the bacteria are healthy and happy they usually demonstrate this by growing nice thick, fat and rubbery SCOBY houses – and fast! If your kombucha is exhibiting this, with loads of baby SCOBY layers and growth then the chances are that the bacteria are doing ok. If you have a large amount of visible yeast strings as well, it could be a good idea to reduce these a little before they start to get out of hand.
The best indicator of how your SCOBY is doing is the kombucha which your ferments produce. If it has fermented properly, in the usual amount of time, smells and tastes good – then things are usually fine. If you are having brewing problems however – and SCOBY growth problems, then it might be time to check in with your culture and figure out how the relationship between the yeasts and the bacteria is doing.
For more information on encouraging the bacteria and discourage the yeasts, you can also read How to Decrease Yeast Population in Kombucha. If the opposite occurs and the yeasts start to decline too much, check out How to Increase Yeast Populations in Kombucha.