Proofing a spirit accurately without using a hydrometer

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Alchemist75
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Proofing a spirit accurately without using a hydrometer

Post by Alchemist75 »

So I'm posting in this category as I'm not clear that there's a better place for this....
The topic came up in another discussion in the forums but I feel like this is it's own subject. There's a little technique I developed 15 or so years back for proofing hydroethanolic solutions with a graduated cylinder and a single drop of basic cooking oil. In the course of my many observations in my lab I noticed that cooking oil sank in pure ethanol and floated in pure water. I started to wonder at what specific concentration of the two liquids the bead would either go from sinking to floating and vice versa. The basic observation was thus:
Oil floats below at or below 50% ethanol concentration and sinks at or above 60%. In the 10% gap between these to marker points the oil will kinda float in middle point in the solution. It occurred to me that if I added either 95% ethanol to solutions below 50% or pure water to solutions above 60% in carefully measured amounts that I could get a gauge of the percentage of ethanol content reasonably accurately, accurate to as little as a 5% range of error as it turned out.
It goes like this:
-at room temperature I.e. 75 degrees Fahrenheit place a 20 ml sample of the spirit into a 100 ml graduated cylinder. (It is possible to use smaller samples in smaller cylinders)
-put a single drop of cooking oil into the cylinder.
-if the oil floats then add enough room temp 95% ethanol in small increments (1 ml ideally) until the oil sinks.
-if the oil sinks in your initial sample then you add room temp distilled water in controlled amounts until the bead floats.
-in the event that the oil neither quite sinks nor floats then the solution is at about 55%.
-as you add one liquid to another you aught to shake it up to get adequate mixing between the water and ethanol. It's a bit slow and tedious but it works well. Also, the exothermic reaction between water and ethanol can throw results off more than 5% in some cases so just take it as slow as you can tolerate.
-in either case note carefully how much liquid you had to get to one of the two marker points. Now follow this basic hypothetical equation:
The oil floats in your 20 ml sample so suppose you added 5 ml 95% ethanol and the oil bead now sinks to the bottom meaning that the solution is now 60%. The liquid volume in the cylinder is now 25 ml so find 60% percent of 25 ml by multiplying 25 by .60, 60% of 25 ml is 15 ml. Subtract 5 ml from 15 to account for what you added:15-5=10 which gives you the original amount of ethanol in the 20 ml solution which is to say that our original percentage was 50% +/-5%
Woop! Did ya get all that? Make sense? If not let me know. Now if the oil bead sinks in the original 20 ml sample then we do the exact same thing only this time we add pure water and employ the same math. Piece o cake right? Right. There is one other little hitch here that can complicate life and that is that "pure" ethanol is never above 96.some odd% so if you're adding ethanol to get the bead to sink you gotta figure for the minute amount of water that's present. Huhhh, headache I know but here's how its done: so you added 5 ml 95% ethanol to the original sample: 5 X .95=4.75 meaning that .25 ml of this is actually water so the amount of ethanol you added was in reality only that 4.75 ml and that's the number you have to plug back into the basic equation. Bleh!
I rarely use this technique on anything below 60% partially because I double run everything and partially because proofing solutions below 60% is a mathematical rats nest plus it means I have to go out and buy everclear just for that purpose.
Often I don't bother proofing any more because I already know that my set up will consistently yield a steady 85-90% after a spirit run so I just cut it back 50/50 to get to drinking strength.
When I do my stripping run I use a crude proofing method to determine when to make my tail cut. I simply collect 3-4 drops from my condenser on a room temp spoon and see if I can light it on fire easily. Once it gets to a point where it's not lighting anymore I know that the product has fallen below 40% and I end the run. Alcohol won't light below 40% at room temp.
So there it is, my oil bead proofing trick. Questions and comments are certainly welcome.
Last edited by Alchemist75 on Fri Sep 01, 2017 11:29 am, edited 2 times in total.
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Still Life
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Re: Proofing a spirit accurately without using a hydrometer

Post by Still Life »

Isn't this a contradiction?
Alchemist75 wrote:Oil sinks below at or below 50% ethanol concentration and floats at or above 60%....
-put a single drop of cooking oil into the cylinder.
-if the oil floats then add enough room temp 95% ethanol in small increments (1 ml ideally) until the oil sinks.
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Re: Proofing a spirit accurately without using a hydrometer

Post by Swedish Pride »

I would not try to proof without a hydro
but if I really had to I Know that boos burn on a plate a at about 40% and in a shotglass at about 50%
Don't be a dick
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Kegg_jam
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Re: Proofing a spirit accurately without using a hydrometer

Post by Kegg_jam »

Not to trying to be rude, but I'd much rather spend $8 bucks on a proof and Tralee.

Interesting observation though.
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Alchemist75
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Re: Proofing a spirit accurately without using a hydrometer

Post by Alchemist75 »

Woops, sorry, that is a contradiction, I'll edit it. Nah, it wasn't something I ever viewed as being a replacement for a hydrometer but it was mentioned in another discussion and there was some curiosity expressed so this is the write up on it. It's as much of an oddity as anything.
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Re: Proofing a spirit accurately without using a hydrometer

Post by Pikey »

Heh - Heh :thumbup:

Like it 8)

Never in the foreseeable future am I likely to try it out, But it is there in the back of the mind, "Just in case" someone is prepared to make a bet on it ! :twisted:
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Re: Proofing a spirit accurately without using a hydrometer

Post by captjack6 »

Very interesting, thanks for the posting. After a few tastes I would be all mixed up though. LOL Might be a good science project for some young student.
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Alchemist75
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Re: Proofing a spirit accurately without using a hydrometer

Post by Alchemist75 »

Honestly if I'm bothering to proof finished product I only use this method to get the ball park reading. This is a single example of a large number of novel qualitative/quantitative test methods I've come up with over the last 20+ years. I have enough of this kinda stuff in my notes to devote a treatise to it. Some of it is kinda cool if nothing else. I do a lot of messing about with subtle principals as much for fun as understanding. Ask me about van der waals forces some time and prepare to be bored to death as I go into fine details of disrupting electrostatic fields, ph affect on solubility, colloid manipulation and why specific types of table salt will induce flocculation better than others....Long nights spent doing shit in a lab that even the most knowledgeable chemist would raise an eyebrow at...
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Kareltje
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Re: Proofing a spirit accurately without using a hydrometer

Post by Kareltje »

The density of vegetable oil varies between 0,91 to 0,95 kg/l. So I doubt if you can ACCURATELY proof a spirit with this elaborate method.
Very cleverly found, though! :clap:
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Alchemist75
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Re: Proofing a spirit accurately without using a hydrometer

Post by Alchemist75 »

Well that probably accounts at least in part for the +/-5% error. Temperature seemed to be a very noticeable contributer to error range. Room temperature is rarely perfect and there is a certain degree of warmth generated by the mixture of higher proof etoh with straight water. I noticed variances of 10-15% with relatively minor changes in temp.
Ideally, and obnoxiously enough you would calibrate the test to the oil being used and the temperature of the liquid.....not that I really recommend it mind you but it can be done lol
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Re: Proofing a spirit accurately without using a hydrometer

Post by Worm_Drippinz »

Shake the jar on its side.


If the bubbles turn to wasp nests and disappear quick, it's 100 proof +.

Longer it takes for the nest to disappear, the lower the proof.


Bubbles to the outside edge/ disappear quick= high proof

Bubbles towards the middle only and might just float around a while= lower proof
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Alchemist75
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Re: Proofing a spirit accurately without using a hydrometer

Post by Alchemist75 »

Well that's the classic shiners method right there. I've used that trick in the past, not as finessed as what you're doing though.
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Re: Proofing a spirit accurately without using a hydrometer

Post by Worm_Drippinz »

Yup.

Thread title = my reply.


Cheers!
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Re: Proofing a spirit accurately without using a hydrometer

Post by Tater »

I use a pot still.Sometimes with a thumper
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Re: Proofing a spirit accurately without using a hydrometer

Post by ga flatwoods »

Nice reference and good reread Tater. Thanks!
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