How to Brew Kombucha with Less Caffeine
The history of kombucha and the history of tea are part of the same story. The caffeine-rich leaves of the Camellia sinensis plant proved to be irresistible to the people of southern China, where the first tea bushes grew.
When the Chinese started brewing the tea and adding sweetener, the resulting blend also proved to be irresistible to the microorganisms that make up the SCOBY (Symbiotic Colony Of Bacteria and Yeast). Part of the reason for this attraction is the sugar compounds that the yeast and bacteria feed on, but another important part of the connection between the SCOBY and the tea leaves is the caffeine and other nutrients and phytochemicals that those particular varieties of plant produce.
While it’s possible to brew kombucha tea using herbs and other plants that don’t contain caffeine, over the long term this will damage the health of the SCOBY. However, there are some things that you can do to reduce the caffeine in your kombucha and still keep your SCOBY healthy.
How Much Caffeine is Left in Kombucha?
The truth is, the amount of caffeine left in your Kombucha really depends on a number of factors:
- your specific SCOBY culture
- what type of tea you use (green, black, white, etc)
- how much tea you used (i.e. tea concentration)
- how long you steep the tea
- how long you ferment the Kombucha
However, there’s been a few studies done on this one done (such as one by Jayabalan et al. (2008) ) found that caffeine concentrations dropped after 30 days of fermentation, stabilizing at about 200mg/liter. This is roughly in the range of 50 mg per 8 ounces of tea (basically a strong cup of regular tea).
As a rough rule of thumb, Kombucha will have about 1/3 to 2/3 of the caffeine levels that you initially started out with in the tea. Again, the factors given above will impact the exact levels.
Caffeine Levels Compared
1 cup (8 ounces) of black coffee has about 100mg
1 cup (8 ounces) of decaf coffee has 5mg.
1 cup (8 ounces) of black tea has between 30 – 80 mg of caffeine
1 cup of homemade black tea Kombucha 10-25 mg of caffeine
1 cup of homemade green tea Kombucha 2-3 mg of caffeine
1 cup GT’s Kombucha between 8 mg to 14 mg of caffeine
So my rough estimate is anywhere from 2 mg to 50 mg per cup of Kombucha, depending on the tea and fermentation length. However, you can easily ensure your Kombucha is between 2 to 10 mg just by choosing Green tea and fermenting your kombucha longer.
How to Reduce Caffeine in Kombucha
You can do one of these or combine them (which will further reduce caffeine content of the resultant Kombucha).
If you want to completely eliminate caffeine in your kombucha, check out our How to Make Caffeine-Free Kombucha article. And for the complete oppposite, you can make an even richer caffeine Kombucha drink by making Kombucha Coffee (called Koffucha).
Use A Different Tea
The choice of tea plays a role in how much caffeine is in the brew. Any of the types of tea for kombucha that come from the Camellia sinensis plant will give you a good nutrient liquid for feeding the SCOBY, but each type of tea has a different caffeine content, due to the way it’s processed.
Oolong tea has an average of 60 milligrams of caffeine for every 8 ounces of tea. This is a semi-fermented tea; the leaves are bruised and partially dried to oxidize the tea, and then the tea leaves are fully dried at a high temperature.
If you want an even lower caffeine level, you can use yerba mate, made from the leaves of a South American shrub. This tea-like drink is a traditional beverage in many native cultures of the region. There is an average of 40 milligrams of caffeine for every 8 ounces of tea made with yerba mate. However, because the yerba mate leaves don’t contain all of the other nutrients that the SCOBY microorganisms depend on, you should treat yerba mate as any other herb tea (see below).
Use Less Tea
While the SCOBY does depend on the organic components of tea leaves to get all of the nutrients it needs, that doesn’t mean that it always uses all of them. In other words, you might be brewing a tea that has more nutrients than the SCOBY can use – and that means more of the caffeine will stay in the tea when you drink it. Try cutting back on the number of tea bags, or teaspoons of loose tea leaves, that you are using. Keep a notebook to track how the changes in the amount of tea affect the brewing time, the flavor of the kombucha tea, and the long-term health of your SCOBY population. Start by reducing the amount of tea in the standard kombucha brewing ratio by one tea bag (or the equivalent) and go from there.
Shorten the Steeping Time
The longer you steep the tea leaves in the hot or boiling water, the more caffeine is extracted. Leaving the tea bags or loose-leaf tea in the water for 5 minutes will extract 50% to 75% of the caffeine, so if you leave the tea in the water longer than that, you’ll get even more caffeine. However, a shorter steeping time also will lower the the level of the other nutrients in the tea that the SCOBY needs to stay healthy.
Extend the Brewing Period
Studies have shown that the kombucha microoganisms rely on the caffeine to build nucleic acids as they grow, and that means that they’re breaking down the caffeine molecules as they use them. And what that means is that the longer the brewing process goes on, the less caffeine there is in the end. Up to a quarter of the total caffeine is used by the SCOBY during the first fourteen days of the brewing cycle, and the caffeine continues to slowly decrease after that. If you’re only brewing your kombucha tea for 7 to 10 days, try extending the fermentation for another week by lowering the temperature of your brewing container, or providing more sugars for the SCOBY to use so that your brew does not get too sour during this longer fermentation period.
Decaffeinate Your Tea
Obviously, if a quarter to half of the caffeine is used by the SCOBY, that leaves half the caffeine still floating around in the kombucha tea. It’s logical to conclude that if you remove that unused half before you add the SCOBY, you should have a nearly caffeine-free kombucha tea at the end, without damaging your SCOBY.
The easiest way to reduce the caffeine in your tea is to use what’s called the “Swiss Water Method” for making decaffeinated coffee, which works for tea as well.
- Bring two cups of water to a boil and remove from heat. Let cool for 5 minutes.
- Place your tea bags or loose tea into the water and stir well.
- Steep the tea for 2 to 3 minutes, stirring regularly.
- Strain out the tea leaves or bags, and throw away the liquid.
This will remove between 40% and 60% of the caffeine in the tea leaves, which you can then use to brew your sweetened tea mixture as usual. Many of the other nutrients in the tea leaves only come out with a longer steeping period, so they will still be there for the SCOBY to use as food.
NOTE: There’s a detailed study from 1996 titled “Tea preparation and its influence on methylxanthine concentration” that was published in the Canadian journal Food Science International that gives all of the details of exact caffeine levels in various types of tea, and if you’re interested, you can download it here.
Brew Herbal, Store Caffeinated
One way that you can create the non-caffeinated kombucha while still keeping your SCOBY healthy is to make sure that you feed it with the caffeine it needs more often than you “starve” it while making your own kombucha tea. Once you have a supply of SCOBYs, you can rotate them out of the SCOBY hotel as you brew, rather than using one SCOBY over and over again. If you fill your SCOBY hotel with a strong black tea mixture the SCOBY can refresh itself with the nutrients from the tea. With three or four SCOBYs, you can rotate them in your brewing so that each SCOBY has several weeks or months in the black tea before you use it to make an herb tea kombucha.
NOTE: Yerba mate, which is classified as an herb tea, does contain caffeine.