Length of time for proofing to "Complete"?

[kckadi]

Out of curiosity, when proofing how long do most of you wait for a proof to complete and stabilize at a final proof? For example I'm currently proofing down about 90 WG of 192 proof(corrected) vodka down to 80 for bottling. I typically add 90% (by weight) of the required amount of water, give a 3 or 4 minute stir and typically let it sit for day (stirring occasionally). I check proof and repeat the process until I reach my target proof.

My question is how long does it really take for the water/alcohol to reach its final, stable proof? Do I need to let it sit for day(or overnight) or do I just need to let it sit for an hour or two? I've tried to find some scientific literature on it but no luck. Is the wait just related to how long the water/alcohol exothermic reaction takes to complete?

The time wait is not hurting my production time but I would like to know for the future.

[John McKee]

This really depends on mixing. I can't offer a definitive time, but if you're able to mix, turn over the tank with a pump system, or otherwise encourage the blending of the two materials you can probably get this done pretty fast. We have various sized proofing tanks, from 250g to 2500g (with differing types of mixer systems in each size) we can get to a homogenized proof within less than an hour.

If you just let it sit, I really can't say when you'd be at a uniformly proofed mixture.....but it could take a long time.

Sorry I can't be more specific.

Cheers,

McKee

[kckadi]

I guess its finally time I invest in an air powered mixer or pump.......

[Absinthe Pete]

Kckadi, the way you do it, is the way I do it. Basically, as you mention, once you mix the water in the reaction takes place which raises the temp and then it's too warm to proof. I have temp correction tables, but proof is never that accurate when it's quite a bit warmer than what your hydrometer's are calibrated too. I mix with a power mixer with a high velocity shear for 15 minutes, take a temp and proof reading, correct for temp, then wait a day for it cool down and the numbers are always off, not off by much, but enough to make a difference. Now if you're using a densitometer or some other device I can't comment on those devices.