Booker's Small Batch Cask Strength Bourbon Whiskey

[Boda Getta]

I just read a description of the above, which claims it is 127.5 proof. I use 3 gal kegs and usually keep my stuff in the keg from 1 to 3 months (depending on how used the keg is) and always lose some proof during the process. Given that their bourbon has to go into the 53 gal barrels at no higher than 125 proof and is aged "from 6 to 8 years". I have read that the "Angels Share" is usually around 3% per year and would think that most of that loss would be the alcohol evaporating through the wood. Going in at 125 proof and coming out at 127.7 after 6-8 years, am I missing something?

BG

[Jimbo]

Proof can go up or down from barrel aging. If the environment is humid, you will lose alcohol and go down in proof. If the environment is dry you will lose water at a higher rate than alcohol (water molecules are much smaller than ethanol molecules) and the proof will rise.

[der wo]

I have the information, that the loss of volume is 2.5% per year normally. If you start with 100gal, you have 97.5gal after one year.
The loss of proof is less. If you start at 125, after one year you will have 124.5 normally. If Booker's is bottled with 127.5 after 7 years , perhaps they started with 131. But so it's not allowed to name it bourbon...
Another explaination is: The proof can rise, if the cask is placed in a very dry but alcohol rich environment. For example under the roof of the warehouse. In this case you will loose much volume but the proof rises.

[DeepSouth]

Booker's isn't made by Buffalo Trace, but the other thread about their antique collection got me to thinking about this. On their website, for each brand of the antique collection they give a list of the features of that year's bottling. This includes the basic recipe (no actual grain percentages, only which specific grains were used), types of fermenters used, distillation method, proof of the still, barrel entry proof, barrel locations in which warehouse, number of barrels selected for that batch, average evaporation loss, and bottling proof. Some of the brands in the antique collection have more evaporation loss than others.

For example, this year's bottling of George T. Stagg is 15 years old and had a final proof of 138.2, even though it went into the barrel at 125 proof. 84.46% of the whiskey evaporated during aging. The barrels in this example lost on average 11.7% of their contents every year.

This year's bottling of Eagle Rare 17 lost 66.1% of the whiskey during the course of 17 years. This works out to an evaporation loss of 6.2% lost on average per year. The Eagle Rare barrels only came from the 1st, 2nd, and 3rd floors of two different warehouses while the Stagg barrels came from multiple warehouses and floors 1-7. It would make sense that barrels in the higher floors will have higher evaporation losses because the temperatures there are much higher during the day.

As an addendum, the average evaporation losses were calculated using an exponential loss formula. For example, if you lost 25% of the whiskey in 10 years, that would not be an average loss of 2.5% per year, but would actually be 2.83% loss per year.

[der wo]

Interesting info.Thank you. Of course I knew, that the angels share can vary, but I did not know that some loose that much so fast.
My numbers are not from american distilleries, they are scottish. It's another climate too.

[just sayin]

I have alway read that in the cool moist environment in Scotland's dunnage warehouses ABV drops and in Kentucky's high hot rickhouses the ABV increases.

[der wo]

If the environment is dry you will lose water at a higher rate than alcohol (water molecules are much smaller than ethanol molecules) and the proof will rise.

You mean, because smaller molecules permeate the wood easier? Or for another reason?

[Jimbo]

If the environment is dry you will lose water at a higher rate than alcohol (water molecules are much smaller than ethanol molecules) and the proof will rise.

You mean, because smaller molecules permeate the wood easier? Or for another reason?

Yes exactly.

[der wo]

Do you think, this is an argument against aging with sticks and loosely open carboys? Because in this case the alcohol will decrease more than the water compared to barrel aging and it is a total different thing? Regardless there is no better alternative for small batches?