As a follow-on to my two-week-old post about kombucha made with spiked tea, and my one-year-old post about kombucha made with vinegar-extracted tea, I made kombucha with tincture of tea. For the tincture, I steeped 1/2 cup of organic Ceylon tea in 1/2 cup of Exclusiv Vodca (vodka) for almost six months. At the same time as the tincture-based kombucha, I made a batch of kombucha using 1/2 cup of organic Ceylon tea that I purchased from the same bulk bin at the same time as the tea used for the tincture.
After 21 days, each one had a pH of 3.2. The one made with the usual long-steeped tea extraction process was pretty normal in scoby, flavor, and everything else. The tincture-based kombucha had a scoby that was thin, weak, and very dark. It had a large quantity of dark “strings” hanging form the scoby, which I’ve read is yeast. The flavor was less sour and more complex than the normally-produced brew (or perhaps more complex flavors from the usual brew were more easily perceived without being masked by acetic flavors).
The interesting thing here is that, in a normal kombucha ferment, the yeast starts to work right away, turning feeding on the nitrogen in the tea and turning the sugar into alcohol. The bacteria also feeds on the nitrogen, but it essentially “lies dormant” until there is alcohol it can turn into acid. (Some yeast also creates acid, but that tends to be dwarfed by the described processes.) I would expect that using a tincture would allow the bacterial fermentation to progress farther than is typical, resulting in more acidity, but that clearly was not the case. It appears that the more efficient tea-extraction benefited the yeast and stunted the bacteria, but I don’t understand why. In hindsight, all of my kombucha spiked with vodka have had a milder acetic flavor, but the non-tincture ones had a scoby that was even more thick and smooth than usual. So it seems the flavor difference is due to the alcohol, and the yeast/scoby effects are due to the tea extraction.
Many people try to avoid letting the yeast-bacteria symbiosis sway too far towards the yeast, though I don’t recall ever seeing any sort of explanation as to why. If this is a concern of yours, you may not want to try using a tea tincture. A future experiment may try making kombucha with different amounts of tincture to see how much more efficient the alcohol extraction is, and if adjusting the tincture volume to achieve relatively-equivalent amounts of tea-extract produces relatively-equivalent batches of kombucha. (It may not, since the alcohol probably pulls out substances that are not extracted by water, in addition to pulling out larger quantities of the same substances pulled out by the water.)