kombucha wine/mead experiences

[jens183]

I did make some batches of kombucha with honey and sugar as the fermentable maybe a year ago. My motivation then was just to make a non-alcoholic soda kind of drink.
The recipes I used then were diffuse and I did not measure the gravity(maybe around 1.040) etc, but the results was decent.
The kombucha-culture eventually got contaminated and started producing some nasty/ill tasting off-flavours and the "fungus" stopped covering the surface so I threw it on the compost ...

Now I gotten hold of a new culture and are motivated to do a few experiments. I have so far followed the "manual" I got with this culture that was : add 2 teaspoons/bags of black tea and 60-100g(2.1-3.5 oz) refined white sugar pr Liter(1.1 quart). From my calculation that would give a gravity of about 1.040 and a potensial of about 5% ABV when using 100g/liter.
I have now(in the last 30 days) made/cultivated ready for usage about 1.2 US gallon of kombucha liquid.

The point :
First: my motivation is to make a good and interesting tasting kombucha wine that containins "substansional" amounts of alcohol(6%+).
I was wondering about what to expect from higher gravity kombucha-mead/wine making.
-What quantities of alcohol and sugar gravities can I expect the culture to produce and tollerate?
-Can I just increase gravity with adding honey and flavors(tea,fruits,etc) to pre-fermented kombucha liquid and let it do a secondary ferment in an sealed carboy and expect it to produce extra alcohol or will it just become sweet because the culture cannot tollerate gravities above 1.080(or whatever limit)?
*If so should I add wine yeast or just mix it with a high alcohol mead and let the mix age?

I would love to hear about your experiences to learn, clear up confusions and to not "reinvent the wheel" with combinatorial testing.

Jens183

[akueck]

Kombucha doesn't typically wind up with very much alcohol once it is finished. You might have 0.5-2% abv, but that's about it. The culture includes yeast, but also bacteria which converts the alcohol to various acids (thus the sour taste).

To get higher alcohol content, you'd need to shut down the bacteria. The easiest way to at least slow them down would be to eliminate oxygen. Kombucha is usually made in an open container where oxygen is plentiful. If you closed it off with an airlock, the bacteria would slow down and you could get more alcohol left over. However, it would taste a lot less like kombucha without the acid content.

Having a higher starting gravity and a higher alcohol content should also slow the bacteria down, but probably not much until you get to at least 10% abv.

[jens183]

Thanks.

Originally Posted by akueck

... If you closed it off with an airlock, the bacteria would slow down and you could get more alcohol left over. However, it would taste a lot less like kombucha without the acid content. ...

Ok lets say I have some prefermented active kombucha liquid with neglectable amounths of alcohol that had a sg of 1.040 and were fermented in an open vessel.

What do you think about ideas of just doing secundary kombucha ferments under airlock to get alcohol and still getting the kombucha flavours/characters to come through.
For example:
-dissolving fresh honey at a rate of 3 lbs/US gallon of the prefermented active kombucha liquid to give it about a sg:1.110 and ferment the "honey enriched kombucha" must under airlock.
-Or mixing maybe 50/50 of very high gravity honeymust(sg:1.200) and prefermented active kombucha liquid and ferment it under airlock.

This way I dont have to worry about getting alcohol free wine because of to much oxygen available under the ferment and the ferment will have the desired amount of acidity.

I think I read a post by you in another thread about wild yeasts that I cannot find now were you said that a lot of this wild yeasts cannot tolerate much more than about 4% abv and thats why you supplemeted a wild mead with commercial champagne yeast(?). Do I remember right? If that is right I guess I cannot expect much more alcohol than 4% unless I add high alcohol tolerant yeasts.

[akueck]

Not sure how adding more sugar to a finished kombucha would go. It's quite acidic, so you might run into problems with the yeast stalling out at low pH. On the other hand, the yeast in the mushroom is protected by the polysaccharide matrix. Adding more sugar but leaving the colony in there (but eliminating oxygen) might be enough to generate some alcohol in the acidic environment. Not sure, you'll have to try it and see how it goes.

Many wild yeasts do go dormant and/or die when the alcohol content hits a magic number between probably 3 and 10% (it varies for the kind of yeast and where it comes from). Just a few will take you past 10%, and usually those are related to the strains we use for making beer, wine, mead, and whatnot. My personal experience with yeast cultured from the wind had them stalling out with something like 4% abv, but again that will vary a lot by location/season/wind direction.

[jens183]

Ok, thanks for input.

I see from the site "analysis of kombucha" that the specter of microorganisms are pretty big and different from culture to culture and that makes it hard to standarize a ferment.
But anyway using common sense(s) goes a long way ...

I been trying to find some resources/experiences and has found a few.

-The gotmead member 'Sander' in the thread 'barnyard mead' post #1 uses the lees as a kicker in a mead with og:1.052
-This site suggest adding just sugar/fermentables or sugar/fermentables and Champaign yeasts then put under airlock. If adding champagne yeast it can go to 5-12% abv. But the kombucha should not be as sour as vinegar.
-This site suggest mixing fully fermented kombucha tea(but not as sour as vinegar), champagne yeast, sugar(1cup/US gallon)(seems pretty cheap though) then put under airlock.

I found a little info on some commercial lambic style kombucha beers. I have not tasted any of them and are not totally sure if I got it all right, but its my conclusions so far.
-goose island brewery used to brew a kombucha beer called fleur where they mix pale ale beer with fermented hibiscus/oolong kombucha and add some long chain sugars like dextrose to give give the kombucha beer a little more to "work on".
-Unity Vibration brewery(?) brews a non-barley oak aged base kombucha mixed with hops, brewing yeast, raspberries or ginger and probably additional fermentables.
-'lambucha' blend of Lambics and Kombucha.

Common with most of them seems to be that they mixes "not to sour" kombucha, fermentables and additional yeast or an already fermented alcohol beverage , and/or flavors.

So I'm going to give it a go...

Round 1 : Goal is to make a light dry cider'ish sparkling mead.
1.2 US gallon(~4.5 L) mead. Blending 50/50 "not to sour" kombucha, honey, flavour.
A proposed recipe(appreciate inputs):
~3 quart/Liter "not to sour" kombucha with as much yeast lees as possible. Maybe adding some of the mushroom(It might be some other organisms/yeasts locked in the mushroom itself than the liquid) as well, although it might be messy getting it into the narrow neck demijohn.
~1.5 kg(3.3lbs) light raspberry honey(gives honey at ratio of 3lbs honey/US gallon). Or less for faster aging.
~2oz(I dont know what amounth is reasonable) dark pulped and frozen sour cherries.
water till top.
champagne yeast, cider or ale yeast depending on quantities and type of fermentables
Wait a few weeks and see what happens.

[akueck]

Awesome! I haven't had a chance to try those blended kombucha/lambic things yet. But thumbs up for experimentation and let me know how it goes. I might start one of my own in a few months.

[jens183]

I just updating :
I made ~4.5 Liter today. The recipe I used in details was :
30.March.2012

~2-2.5 Liter kombucha (just liquid with all the lees, did not use any of the mushroom itself)
~1.2 kg raspberry honey
~200g pulp of sour dark cherries
1 pack(5g) red star pasteur champagne yeast(The yellow package)
OG : 1.080
PH : Not measured.

And the procedure I used was :
*Filled about half the 4.5 Liter(1.2 US gallon) demijohn carboy with kombucha. Gives about 2-2.5 Liter(2-2.5 Quarts)
*In Ken schramm's compleat meadmaker p.117 he recommends using 72-120g/liter of tart cherries to get a mild fruit character in a mead. I just had about 200 g in total(~50g/liter) in the freezer so I used that. I gave the cherries a quick boil.
*Mixed the filtered "raw" honey into the liquid with a handheld mixmaster. Whipped it for about a minute(?) till it was a decent amount of foam.
*rehydrated the yeast about 15 min. Added last.

The recipe I used to make the base kombucha about 2 weaks ago was :
Total 4L with the starter. Fermented in an wide round goldfish aquarium bowl.
*300g white refined sugar. Did not measure the gravity, maybe it was 1.030(?).
*Tea of 6 * 2g ceylon black tea bags and 2 * 3.5 g tea bags of mix hibiscus/rosehip
*0.8 Liter starter and the mushroom from last ferment.
~14 days fermentation at room temperature ~20C(68F)+-
-The fermented kombucha tea tasted more sour than the "not to sour" I planed to use. The tea also tasted a little diluted so the next time I might make it more flavor concentrated by adding more tea and sugar. Other than that it tasted like homemade kombucha like I remembered it with no offensive flavours.

I will update the progress later ...

Jens

[jens183]

Its been about 2 weeks.

The fermentation has been snailing along with something like 1 bobble in the airlock every ~30 second at the most. Its been fermenting at temperature between 16-20C(59-68F).
This stuff has not seemed to be doing very well at all(maybe not surprising). probably as akueck said in post #4 it is very acidic so I ordered some ph testing strips raging from 0.5-5(the best narrow range I could find) and some calcium carbonate.

I did a few measures just now. The Gravity is ~1.055 and ph(The strips go on a 0.5 increment) seem to be(on eye measure) between 2.5-3.0 . I'm not totally convinced that the lost gravity(~1.030) has turned into alcohol, but the high sugar content might be masking some alcohol taste(I dont know).
By the way : Does sugar into other things than alcohol like sugar into acid lower the gravity the same way sugar into alcohol does?

At the moment it taste sour, sweet, diluted...decent, but not very interesting. I cannot taste any noticeable amounts of alcohol and it is basically a overly sweet soft drink at the moment.

I got a couple of questions.
1)My understanding is that some of this wild ferments need forever to finish. Should I just leave it and se what happens or favour the champagn yeast by increasing the ph?
2)If I should increase the ph: How much calcium carbonate(Its the only ph increaser i've got) should I add? Should I boil it before adding or just add it dry?
3)In general is there any specific fruits and amounth that can work as a "ph base" raising the ph or gives some kind of good ph buffering capabitities on a mead/wine to keep the ph at the optimal range(?) 3.7-4.6?

Any other inputs/ideas?

Jens

[akueck]

I'd be tempted to just let it go and see what happens. Might be neat to have a naturally sweet kombucha drink.

I'm not sure how much the alcohol to acid conversion changes gravity. I'd guess not a heck of a lot. You can go figure it out if you like, you just need to know the chemical reaction and the molar masses of each product that stays in solution.

More sugar definitely makes gravity go up, regardless of pH.

[jens183]

Ok. I forgot to mention. I originally reserved about 0.5 liter/quart of empty headspace for an eventual vigorous ferment(that never arrived). I topped up that headspace yesterday with just strong black unsweetened tea before taking the gravity read. So in reality the original gravity(80) 2 weeks ago was based on 4-4.5 Liter, and the gravity yesterday(50-55) was based on 4.5-5 Liter so was difference in gravity is a actually a little less.

Originally Posted by akueck

I'd be tempted to just let it go and see what happens. Might be neat to have a naturally sweet kombucha drink.

yeah I can just leave it for now and take some gravity and ph readings in an months time. Pretty darn sweet at the moment though(1.055!)

Originally Posted by akueck

I'm not sure how much the alcohol to acid conversion changes gravity. I'd guess not a heck of a lot. You can go figure it out if you like, you just need to know the chemical reaction and the molar masses of each product that stays in solution.

Ps. Im not a chemist or anything like that(only had a few "forced" courses) and its not maybe that important, but just out of curiosity. Isnt the gravity a measure of density in an liquid for example? It seems from that table that the different alcohols(including ethanol) are like close to ~785 kg/m^3(lighter than water), Acetic Acid ~1049.10 kg/m^3(about equal to water) and water 1000kg/m^3 .

But anyway ... I will update later.

Jens

[jens183]

More about sour gravity readings.
I got another sour ferment. A unhopped wild sour fermented malt beer that had a original gravity 1.060 that I started 26.feb.12 with some active wild organisms. I racked that ~one a week ago and tasted that it was extremely sour, I thought it had fermented all sugars and did not even bother to take any gravity readings and just considered it a "semi" failure(It was suposed to be a little alcohol in it, but was/are still extremely good tasting, sour, refreshing).

But that point was : I did take a gravity reading just now that read 1.040(a normal beer would probably end up with something like 25% unfermented sugars(?) maybe ... 1.015 ) and it was slightly alcoholic(just drank a pint of it "in the name of sciene" to be sure). The ph was around 3. It has been quiet in the airlock since I racked it(seems stable).

What should I put in that? Does the sour beer still have fermentable sugars and the activity just stalled because of acidity?

[akueck]

Some wild ferments just take a long time to complete. It might not be very active in the airlock, but could still be going. Some bugs turn sugar into other things without the release of CO2.

The acetic acid gravity you've got is for pure acetic acid. So hopefully you don't have that.

[I am not a chemist either.]
If we look at Ethanol and Acetic Acid, we go from CH3CH2OH to CH3CO2H. So you might write it down
CH3CH2OH + O2 --> CH3CO2H + H2O
Sure that looks ok to my 11:30pm brain.

Since the O2 should not contribute to the SG on the left side, you've basically added it to the solution. Right? Sure. So the mass of your solute goes up a bit by converting ethanol to acetic acid. Presumably SG also goes up.

The SG drop by turning sugar into ethanol in the first place should still be larger. So overall the gravity should still drop, but less than if you were making an alcohol-only mead.

[danielgoodman]

Hi Jens,

I made an account just to encourage you to keep us updated; I am really interested to see how this turns out and I hope it's tasty!