Many kombucha purists often drink plain kombucha tea, which does the job most of the time, but some of us are looking for something a bit stronger.

Kombucha naturally contains <1% alcohol as a product of the yeast fermentation.  The SCOBY contains many different types of yeast that act as a source of ethanol for consumption by the bacteria.  The multitude of bacteria present generally consume alcohol and sugars to produce acetic acid, gluconic acid, and a few other weak acids that all give kombucha its flavor.  When creating high-alcohol content kombucha or kombucha wine we aim to remove as much bacteria as possible to allow the alcohol from yeast fermentation to accumulate in solution.

Luckily, this process has already been perfected by wine makers!  Wine yeast added to kombucha (with the right concentration of sugar) should ferment for up to two weeks and give a reasonable alcohol concentration while maintaining the kombucha flavor.  Not everything has to be complicated...but we sure can make it way.

Where to start

Always start by Googling what you want to do.  Chances are somebody has done it already and their work is in need of some revision.  In this case, somebody is already making and selling high-alcohol content kombucha (I'll probably call it HACK from now on instead of kombucha wine).  Boochcraft says they are the first hard kombucha, but they also teach you how to be not-quite-the-first maker of hard kombucha!  Don't let the search stop there...many other people post about how to make kombucha wine.  Here is the most comprehensive guide that I have seen.  All the other content they have on their site is just as helpful, I highly recommend turning to them for a greater depth of knowledge.

So with a good layout of the general process, how do we choose which wine yeast to use? First we must turn to Mayer-san.  If you haven't seen the name elsewhere on the site, Eric Mayer is the neighbor to my childhood home.  I've learned a lot about gardening, making wine, beer, yogurt, all sorts of things.  He pointed me to two white wine yeasts, both very common.  I purchased both Premier Blanc and Côte des Blancs yeasts from Label Peelers (they offer free shipping).  

Batch 1 

Started 3/21/2020, bottled TBD

My plan is to do a small first batch since I don't have a hydrometer to test for sugar content or expected alcohol.  I currently have one gallon of kombucha that started only a week ago from starter liquid.  The SCOBY is a good size on top and there is definitely strong kombucha flavor to the brew.  My main concern is that the starter liquid will be active enough to create a new SCOBY and the bacteria culture will overpower the yeast.  I did my best to remove all of the SCOBY, but I now regret not emptying and refilling the carboy.

I did not have a lot of strawberries, but enough that the flavor should come through behind the kombucha flavor.  I removed the stems and diced them into small pieces.  Following the advice on this blog to start processing the strawberries.  I added all of my diced strawberries to a bowl with 1 cup of sugar.  After this had rested for several hours, I started on the yeast.  Côtes des blancs yeast produces a fruity flavor and is recommended for ciders and fruit wines, so that seemed like a better choice to start compared to Premier Blanc.  To bloom the yeast, I followed the package instructions to add to warm water and set for 20 minutes.  The yeast foamed as it was supposed to, so I added it to the main carboy with the sugar and strawberry slurry.  To make sure I got all of the sugar and strawberry juice I added 1 cup of warm water to the bowl and rinsed it into the carboy.  My current overall volume came to 1 gallon and 4 cups or 5 quarts.  I had considered adding more tea instead of warm water, but the payoff did not seem worth it.  I will consider adding more fresh sweet tea in the next batch.

Observations

Immediately, the mixture started to fizz from the activation of the new yeast.  After settling for an hour, I noticed a thin film on the surface.  The strawberries are floating which obstructs my view, but it looks very much like a SCOBY.  I will continue to watch out for that, even though I have absolutely no plan to control it.

As of 3/28/2020

One week later, the top layer still looked like a SCOBY, but I am less fearful of that now.  The strawberries faded to off white a few days ago, no change in their buoyancy.  The smell does not seem as acidic as normal kombucha.  A hint of alcohol scent comes through, so it seems like the alcohol is not being consumed by bacteria. The rate of gas formation has changed over time, but it has not slowed as much as I expected.

The data for the rate of bubbles is below.

4/4/2020

Same update as last week.  Looks about the same as last week.  It seems that more sediment has fallen to the bottom of the carboy, but difficult to see clearly.  The liquid is still very hazy.