I'm frequently asked about caffeine and kombucha, and caffeine content of kombucha in general. This consideration has immediate repercussions for many people, such as those allergic to caffeine, to those who are very sensitive to its effects. As such, there is a lot of interest for kombucha brewers in the range of caffeine one can find in kombucha. Today I'd like to discuss the making of kombucha without, or with very little caffeine.
*Contrary to some opinions I've heard, it has been verified that caffeine content in kombucha does not decrease during fermentation.* (from Michael Roussin's "Analyses of Kombucha Ferments," a great paper that can be found here)
**The kombucha recipe Kombucha Brooklyn provides, and that we brew with, calls for 3/4 less dry tea than does the same amount of tea you would drink, say at 2pm with snacks. That means 3/4 less caffeine than a standard cup of tea.**
Firstly, I'd like to provide a disclaimer. One of the major tenets of KBBK philosophy holds that kombucha brewed without tea (camellia sinensis) will not always reliably change from sweet to fermented, and if it does, you will find it very difficult to sustain a culture on these tisanes, herbal teas, or otherwise. Whereas you can usually get one or two ferments successfully, at most, from non-tea containing brews (grape juice, coconut water with pineapple, barley and rooibos), you will not be able to sustain a SCOBY with these seemingly normal foods that are actually alien to your culture.
As I sat pondering this issue, I started to consider other fermented beverages with foods that provide a good nutrient profile suitable for feeding yeast. My first thought was beer; then I remembered something my co-worker Anna had brought in to our office, that we enjoyed immensely when steeped as a tea - roasted barley. Bingo! I wanted to brew a kombucha that had greatly reduced caffeine, and it seemed barley might be the key. Another of my favorite alterna-"tea"ves, rooibos, came to me as the next best herb to use in this caffeine-free kombucha admixture. Said to have been cultivated by Dutch settlers of South Africa as a replacement for black tea (then a prohibitively expensive prospect for import), rooibos has become a popular facet of South African culture.
I was relatively sure that a combination of barley and rooibos would ferment just fine into kombucha. As I've been experimenting with many different herbal additions to traditional kombucha teas (which have been pretty much anything camellia sinensis), and discovered that the culture is relatively resilient to such experimentation, I figured diving in head-first would be both fun and informative.
I would call the results highly successful. To fully ferment took about 10 days, when I reached a nice balance of sweetness and acidity, and I was left with a kombucha that had a very malty and tart cherry flavor. Rooibos, tasting a lot like an herbal cherry, undoubtedly was the most forward of the flavors in this brew. My SCOBY wasn't anything substantial, about 2 mm thick, but the 'buch was definitely 'buch. And since I have an essentially unlimited supply of SCOBYs, I wasn't worried about keeping a culture going feeding on this simple, tea-free brew.
The longevity of your culture will however be a great concern to you, the home brewer. You will be able to use your initial, "seed SCOBY" multiple times, but your caffeine-free brew may not produce a nice, thick SCOBY every time you brew, as camellia sinensis is the best food for kombucha. As such, I suggest keeping a container in your refrigerator full of SCOBYs, like the one seen below. You'll want to keep it covered to prevent drying, but each time you have a nice new SCOBY, consider putting it in the refrigerator to keep it as a backup. That way, you won't have to count on your caffeine-free brew producing a SCOBY every week, as you'll have plenty, and this brew won't kill off your original "seed SCOBY" necessarily, it just won't produce a new one.
So, keep these possibilities in mind when you make your next batch, and also remember that experimentation is the spice of kombucha brewing. You may very well find many different mixtures that work for you that don't include caffeine or tea!
Stay tuned - in my next blog, I'll go over making caffeinated and energetic kombucha that will have you jumping for jitter-free joy!