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Need a Means to Test Alcohol Content of a Fermenting Process

08/07/2017 4:45 PM

My wife asked me today how she can test the alcohol content of a fermenting food process (such as a Kombucha, or Kefir strain, as it grows/ferments). She needs to be able to test it several times at monthly (or so) intervals.

Taste testing isn't good enough. We are not drinkers, and wouldn't be able to distinguish content by it's effect on us, as a result. Also, because I know some of you will suggest it, lighting it on fire is out. We need to be able to keep the process alive, not burn it to death.

Thanks, folks.

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#1

Re: Need a means to test alcohol content of a fermenting process

08/07/2017 5:01 PM

If it's liquid, one way is to measure the specific gravity. Or you can check this link.

https://en.wikipedia.org/wiki/Alcohol_by_volume

Kombucha is listed in this link at .5 to 1.5%

http://www.winegrowers.info/wine_making/Alcohol.htm

This little device does it for you :

http://www.bellinghamandstanley.com/ltd/abv_kit.html

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#2

Re: Need a means to test alcohol content of a fermenting process

08/07/2017 5:08 PM
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#4
In reply to #2

Re: Need a means to test alcohol content of a fermenting process

08/07/2017 6:06 PM

1.240 is fully charged...

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#7
In reply to #2

Re: Need a means to test alcohol content of a fermenting process

08/08/2017 2:42 PM

Doesn't he need to know the original gravity (the reading before any fermentation), too, along with the final gravity (reading after fermentation) in order to take the difference and make the multiplication (131.25?). He might be too late for this batch? Or is there another way?

Just asking because that's how I know when to rack my beer using a hydrometer.

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#9
In reply to #7

Re: Need a means to test alcohol content of a fermenting process

08/08/2017 4:17 PM

Good point. I'm so green I never would have thought of that, despite years of experience in formulating, planning, and executing tests that require a baseline before starting.

Thank you.

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#10
In reply to #7

Re: Need a means to test alcohol content of a fermenting process

08/10/2017 5:45 AM

I made wine for years and I agree with you that you can't just measure the final SG and know how much alcohol there is, you need to know what you started with as well. A little advice on using the hydrometer too, when you drop it into the liquid you should spin it at the same time to stop bubbles sticking to it and giving a false reading.

I use the wine book by C.J.J. Berry which states ABV=(Original SG-Final SG)/7.36. When you have an SG of say 1.075 you would use 1075 in the calculation.

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#3

Re: Need a means to test alcohol content of a fermenting process

08/07/2017 5:57 PM

Refractometer.

No association, just found it helpful in my homemade brewing.

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#5

Re: Need a Means to Test Alcohol Content of a Fermenting Process

08/07/2017 8:53 PM
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#6
In reply to #5

Re: Need a Means to Test Alcohol Content of a Fermenting Process

08/07/2017 10:17 PM

Thank you, Jpool, Rixter, SolarEagle, and Kilowatt0. Your answers are all helpful. I'll discuss this with my wife, and we'll see what we have immediately available among the suggestions you offer. I'm most intrigued by the electronic test gear, because it is something my wife can learn easily to use, and get repeatable results. One of those will probably be the answer we use. Regardless, I'll post back here with whatever result we find.

Unfortunately, it will probably be a week or more before I can get back with anything useful here, solely because of work and grand-child schedules, as well as the current state of our Kombucha and Kefir growths.

But I will be back to report, and thanks again.

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#8

Re: Need a Means to Test Alcohol Content of a Fermenting Process

08/08/2017 3:36 PM

I'd go with the hydrometer. Cheap, easy to use, and works on everything from alcohol to black liquor as far as I know.

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