View Full Version : Whiskey Dilution Formula

05-06-2004, 15:18
We talk from time to time about diluting whiskey with water. It's a good idea when doing a comparative tasting to dilute the samples to a common proof. I tried to work out a formula for doing this but it just made my head hurt, so I went looking for one on the internet. I found this and it works. For maximum ease of use (especially if you are a math idiot like me) plug it into a spreadsheet application.

The formula is:

(amount of whiskey) x ((bottle proof/desired proof) -1) = amount of water to add

05-06-2004, 15:25
That's good, and I'll use that next time I do this. But (not to traduce a thread) how do you do the opposite, that is, increase proof, or as a correspondent on the whiskymag.com forum called it, "retro-strengthen" the whiskey? Hint: it involves the application of cold. http://www.straightbourbon.com/forums/images/graemlins/smile.gif


05-06-2004, 17:11
Does that work with whiskey? I wouldn't think that it would. They used to do it in the north with hard cider. Just let it sit out all night. Ice will form on top and that's almost entirely water, so just throw it away. What's left will get up to maybe 60 proof, which is great for raising the alcohol content of a fermented liquid without distillation, but I can't imagine how you could raise the proof of something that's already 80 proof through freezing. People put spirits, espcially vodka, in the freezer all the time and they thicken but they don't separate.

Unless you're talking about something that's been diluted to, say, below 60 proof, then I guess what I described above would work.

05-06-2004, 17:21
On the site I mentioned, the correspondent gives his experience. He refers to a skiing expedition in Japan when it was extremely cold. He had a flask of scotch whiskey, I believe Glenfiddich. He said ice formed in the container and he strained off the liquid to find a very concentrated whisky that was evidently high proof and very savoury. That is what he said. I believe all alcohol will freeze, even spirits, but intense cold is required.

Randy, from your knowledge of chemical engineering, would you concur with the concept of retro-strengthening?


05-06-2004, 17:32
Here's a link to an Alaskan resident who seems to have (somehow) measured/figured the freezing points of alcohol at different proofs (read all the way to the bottom):
Liquor freezing temperatures by proof (http://www.alaska.net/~dogdrivr/bushthermometer.htm)

Don't know how accurate, but sounds about right. According to him, a basic 80-proof bourbon will freeze around minus-30.

05-06-2004, 19:12
I have a deep freezer at work that stays at a constant -30 degrees C. I could give this a try. What bourbon should I try and freeze, and what type of container should I use? Something with a wide surface area?

05-06-2004, 20:18
Jeff, whatever container you use, make sure to give it plenty of room to expand without breaking. Even frozen, whiskey can make a mess. I had a half pint bottle of JD freeze in between the seats of my old jeep years ago and had to take a sobriety test every time a cop pulled me over. Sounds like one of my little quips but it wasn't. It took forever to get the smell out as it seeped under my gas tank (one of the old CJ5s where the tank was under the seat). This was back in about 82 so if any of you can remember what proof JD was bottled at then, you can have some idea of how high a proof will freeze and break. I think the period of time was one of record lows in Missouri about 10 below for a period of about a week.

05-07-2004, 01:14
The person who did this reported using Glenfiddich Solera which comes in 80 or 86 proof. Probably he got it to 95-100 proof or so because it was not frozen completely, just enough to allow ice crystals to form (a slush I think he said) so that some of the water was left behind when the drink was "decanted". Obviously if you do this as Dane said you'd want to be careful to wrap the package well so any breakage doesn't spill anything or do damage. I'd leave it just a short while and monitor it well. Really there is no reason to do this (especially with bourbon which can be bought in higher proofs) but the people discussing it viewed it as an experiment. Some speculated that unless it was done with chemical knowledge the results wouldn't be good because it would be hard to separate just the water, other elements would be left behind as well and taste would be affected. I tried this in my home freezer by first diluting some McKenna 10 year old which allowed it partially to freeze faster than otherwise. I did get a kind of slush and was able to concentrate the drink back perhaps to what it was, but it didn't taste as good as it did. Also, the freezing precipitated a lot of solids, I am not sure what these were, it was thick dark swirly stuff, maybe proteins or tannins. So without them the liquor was not what it was. The people who expressed interest in "retro-strengthening" or one of them felt that some modern whisky (they were referring to scotch) was too bland or over-processed and concentrating to a higher proof might restore some of the whisky's authenticity. Based on my own experiment, I feel there is no reason to do this because we have a good supply in North America of high proof whiskey if we want it (bourbon and scotch too, e.g. the "cask-strength" whiskies) and as I say without the facilities of a proper lab and controls likely it is hard to get good results!


05-07-2004, 06:58
Gary....Using cold temperatures is one way to precipitate (or freeze) out unwanted materials from a solution. These processes are often combined with filtration to trap the unwanted material. In this case, cooling the bourbon, freezing the water and traping the ice in a filter will work. My guess is that at the low temperatures required, other components of the whiskey may precipitate out of solution and also be captured by the filter and may result in a vastly different taste.


05-07-2004, 11:11
Thanks, Randy, and in fact that is what happened even with my rough experiment. There was left behind with the slushy ice a mass of brown particles which must have been tannins, proteins and other components. So the resulting flavour was rather bland.

The freezing technique is used to create certain beers (icebock, notably, which originated in Bavaria but of which we have a world-class example in Ontario made by Niagara Falls Brewing Company), German eiswein (ice wine) where wine grapes' sweetness is concentrated by natural freezing of the grapes in the field, and indeed applejack in certain old methods as noted by Chuck. But the potential of freezing to create beverage spirits seems much more limited or unnecessary, due of course to the efficiency of modern fractional and other distillation methods achieved by steam and other heating processes.


05-07-2004, 14:17
Sounds like the 'cold filtration' method Buffalo Trace and others report using.

05-07-2004, 17:55
"Cold Filtration" for whiskey doesn't get to the point of producing ice crystals. It simply gets the liquid cold enough for the amino acids that are its target to come out of solution. Every whiskey maker uses cold filtration to eliminate flock or chill haze.

05-07-2004, 19:42
Every whiskey maker uses cold filtration to eliminate flock or chill haze.


Is this true for whiskies 100 proof or more? I know many scotch independent bottlings, even under 50% abv, do not chill filter.

Does chill filtering, while preventing chill haze, create a less tasteful product.

05-08-2004, 14:48
You are correct that chill filtering is not necessary for whiskies 100 proof or above, but I can't verify whether or not it is done anyway. In recent years, distillers have begun to admit that chill filtering does affect taste.