Proof?

[Ciderman]

If you have some very accurate scales and an accurate measure jug, you can measure the density that way, and from the table below, get the ABV. Then (roughly) multiply by 2 for proof. (you may need to cut and paste the table elwhere to get it to line up)

Aqueous Ethanol
Density % by wt % by vol g/100 mL Density % by wt % by vol g/100 mL
0.98938 5 6.2 4.9 0.85564 75 81.3 64.2
0.98187 10 12.4 9.8 0.84344 80 85.5 67.5
0.97514 15 18.5 14.6 0.83095 85 89.5 70.6
0.96864 20 24.5 19.4 0.81797 90 93.3 73.6
0.96168 25 30.5 24.0 0.81529 91 94.0 74.2
0.95382 30 36.2 28.6 0.81257 92 94.7 74.8
0.94494 35 41.8 33.1 0.80983 93 95.4 75.4
0.93518 40 47.3 37.4 0.80705 94 96.1 75.9
0.92472 45 52.7 41.6 0.80424 95 96.8 76.4
0.91384 50 57.8 45.7 0.80138 96 97.5 76.9
0.90258 55 62.8 49.6 0.79846 97 98.1 77.4
0.89113 60 67.7 53.5 0.79547 98 98.8 77.9
0.87948 65 72.4 57.1 0.79243 99 99.4 78.4
0.86766 70 76.9 60.7 0.78934 100 100 78.9
To use the above chart, find the density value that is closest to the density that you determined for your ethanol samples. Then, look at the column that gives g/100mL

[possum]

A rough aproximation will give you the indication of Over 100 proof or under.

Try to light a spoonfull at room temperature WITHOUT heating up the spoon.
If it lights easy, without needing to warm up the spirit or spoon, then it is over 50%abv.

Various amounts of dillution and retrying this process will give more precission for high proof spirits. Just make sure you work the fractions out right.

Spirit hydrometers are not expensive, and are worth the $5-8 if you can find one.

If the flame is blue or yellow only tells about the possible impurities (undesireable alchahols), not the proof.

[msrorysdad]

get an alchohol meter off ebay, 16$ with shipping. If you search I believe there's a break down of when it burns here. On a spoon, 100 or above on a plate 80 and above I believe

[hornedrhodent]

Mix with gunpowder and light - if it goes out it's UP - if it flares up it's OP - if it just burns it's proof - I presume you have a source of 18th century gunpowder.


Us modern folk use A/V!

[Cardsharp]

I made myself a makeshift hydrometer out of a pen tube with a couple BBs in it. Floated it in comercial 40% spirit and marked it. It's only good for diluting my spirit, but it works just fine for that. I'd have to suggest something other than a pen tube though, as they are plastic.

[stoker]

I would just buy an alcoholmeter.

I recently saw a movie with the same title as this topic.
a math movie!