Understanding ABV by bubble behavior

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OtisT
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Understanding ABV by bubble behavior

Post by OtisT » Thu Jul 09, 2020 12:10 pm

I found this short article interesting. In summary, A centuries old process used by mezcal makers for understanding a spirit’s ABV based on how long bubbles remain is explained by science. I’ve read about moonshiners also using a visual inspection of liquor shaken up in a jar to see the ABV. Enjoy, Otis

Popular Mechanics: Mathematically Modeling the Mezcal-Making Process...For Science, We Promise
The perfect mezcal produces a specific type of bubble, and that has surprising implications for understanding fluid dynamics.

Read in Popular Mechanics: https://apple.news/ATgJsOmxwSPmxVL5XIvho0Q

Original article with link to study: https://www.futurity.org/mezcal-bubbles ... 2399052-2/

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Last edited by OtisT on Fri Jul 10, 2020 11:36 pm, edited 1 time in total.
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Single Malt Yinzer
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Re: Understanding ABV by bubble behavior

Post by Single Malt Yinzer » Thu Jul 09, 2020 3:07 pm

Thank you for posting this. Gives science background to the moonshiner's bubble proofing method.

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Re: Understanding ABV by bubble behavior

Post by OtisT » Thu Jul 09, 2020 3:38 pm

Single Malt Yinzer wrote:
Thu Jul 09, 2020 3:07 pm
Thank you for posting this. Gives science background to the moonshiner's bubble proofing method.
I want to try this myself now, next time I am making cuts. Just one more way to enjoy traditional methods and it could be a great party trick under the right circumstances.

The study said that a mixture of pure alcohol/water has a different bubble behavior than a spirit with the same ABV, due to impurities in the spirit. 55% was said to be the best ABV for max bubble life in mezcal. So I am wondering what, if any, difference there are in the maximum bubble life ABV for a corn whiskey, wheat whiskey, rum, etc. I can’t wait to try.

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Oldvine Zin
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Re: Understanding ABV by bubble behavior

Post by Oldvine Zin » Fri Jul 10, 2020 9:03 pm

Maybe a fun party trick but I trust my nose and the hydrometer for the end result. But I do have a rather large nose :D

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Re: Understanding ABV by bubble behavior

Post by shadylane » Fri Jul 10, 2020 10:40 pm

Bubbles do seem to raft up more when the abv is 50% ish
They never did say anything about the higher proof alcohol beads that dance in the collection jar.
I've seen beads as big as a goose eye that lasted for several seconds :lol:
If you look close on the video, there's a few tiny beads.
They are completely liquid and focus light, unlike a bubble

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Re: Understanding ABV by bubble behavior

Post by NZChris » Fri Jul 10, 2020 11:06 pm

I reckon my nose can pick out heads and tails better than using my eyes to watch for bubbles and beads, but I still use them as an indicator and record them in my run notes for future reference.

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Re: Understanding ABV by bubble behavior

Post by Setsumi » Mon Jul 13, 2020 11:00 pm

shadylane wrote:
Fri Jul 10, 2020 10:40 pm
Bubbles do seem to raft up more when the abv is 50% ish
In the ferment... or so i read. I would very much like to ferment agave. seems very economical, or did i just read wrong?
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Re: Understanding ABV by bubble behavior

Post by OtisT » Tue Jul 14, 2020 5:52 am

Setsumi wrote:
Mon Jul 13, 2020 11:00 pm
shadylane wrote:
Fri Jul 10, 2020 10:40 pm
Bubbles do seem to raft up more when the abv is 50% ish
In the ferment... or so i read. I would very much like to ferment agave. seems very economical, or did i just read wrong?
They did refer to bubbles in the ferment in the article, but in context they are clearly talking about the product after distillation. The author (and the editor) is obviously not a distiller. Otis
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Re: Understanding ABV by bubble behavior

Post by Setsumi » Tue Jul 14, 2020 7:50 am

OtisT wrote:
Tue Jul 14, 2020 5:52 am
Setsumi wrote:
Mon Jul 13, 2020 11:00 pm
shadylane wrote:
Fri Jul 10, 2020 10:40 pm
Bubbles do seem to raft up more when the abv is 50% ish
In the ferment... or so i read. I would very much like to ferment agave. seems very economical, or did i just read wrong?
They did refer to bubbles in the ferment in the article, but in context they are clearly talking about the product after distillation. The author (and the editor) is obviously not a distiller. Otis
yes.... but if one writes an article for a magazine research should be the basics. and basics should start with understanding the process.... okay, let me put it differently,,, a newbe on here will ask... "i am trying to ferment a 50% wash/ agave/corn... why does it not bead?" boy that would be worse than George and PIDS....

sory, lockdown is getting to me.
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Re: Understanding ABV by bubble behavior

Post by Kareltje » Tue Jul 14, 2020 2:28 pm

From the article:
"The fermentation can last anywhere from a month to 12 years, and makers test small samples to see how that fermentation is progressing.

“The method used to determine the correct alcohol content is of particular interest: a stream of the liquor is poured into a small vessel to induce surface bubbles. These bubbles, known as pearls by the Mezcal artisans, remain stable for [tens] of seconds only if the alcohol content is close to 50%,” the paper explains."
Well there's many a years I travelled a hundred miles or more,
but a fermentation to 50% I have never seen before.

So I guess the writers of the article in Popular Mechanics got their information mixed up.

The second link seems to be more reliable, but this mentions only the distillates, not the ferments.
So while we now know more about the lingering of pearls, we still do know nothing about the fermentations of a month to 12 years.

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