As we know many distillers talk about the water source they used to make their whiskey, some have even had to stop using this same source of water for everything else they do in the plant.

So this started as me taking an alternative thought process about the water usage in a distillery and how all water in the bottle comes from such and such a source...but what if the steam they are using to run the still and strip the alcohol out of the mash isn't from that source... how much of that steam, instead of the water in the mash ends up in the bottle?

At first thought, it doesn't seem like much, right? But thinking about it more, steam has a much lower capacity to hold heat compared to water (less than half, by mass)...it is even lower than the heat capacity of ethanol, actually. Which means you have to pump a hell of a lot of steam into the mix to vaporize the alcohol and the water in the mash to get them to vaporize.

So lets just say they are actually using very hot water to strip the alcohol off (212F/100C) and the mash is 70F/21C and use a fairly simplified version of some math and say that the reasonably low amount of alcohol in the mash hasn't changed the heat capacity enough to bother to take into account.

This means we have to add in enough hot water to raise the temp to 172F/78C, which is the boiling point of ethanol, for distillation to happen.

This means that for every gallon of mash you want to distill you have to add 3 gallons of hot water to reach this temp...

So this means that if they were to distill to only 100 proof, 3/8s of what comes out of the still wasn't ever part of the mash.

Any thoughts? or anyone with a better grasp of thermodynamics wanna correct my numbers to be more accurate?