A few months ago, these (self-proclaimed) “Nerdy Posts” popped up in the Bourbonr Facebook group. They were concise and well researched. And, the feedback and discussions from readers were excellent. I reached out to my friend Henrik Brandt, the man behind the posts, to see if he would be interested in doing an expanded version for the Bourbonr blog. This will be a recurring series on the Bourbonr blog. I hope you enjoy! Henrik is based in Copenhagen, Denmark and is an admin in the Nordic Bourbon Community Facebook group. He will be publishing a book about American Whiskey in November and you can follow him on Instagram via @the_bourbon_nerd
Barrel Entry Proof
Today we look at the term “Barrel ENTRY proof”. This term should not be confused with the almost-similar term “barrel proof”. And to avoid that confusion, let’s look at the latter: A barrel proof whiskey is (typically) not diluted at all – but pretty much put into the bottles straight from the barrel. “Barrel proof” is not an official term, and you will see manufacturers refer to this as “barrel strength”, “cask strength”, “full proof”, etc.
This update is about barrel ENTRY proof and that is something very different – but hugely important. It is also something that the manufacturers tend to keep a little to themselves – and you will know why when you have read this post. “Barrel entry proof” is the proof level of the new whiskey (white dog) that goes into the barrels for the aging process. The new whiskey is normally 130-140 proof when it comes out of distillation – but you have to add water to it, before it goes into the barrels. By law, the proof cannot be higher than 125, when entering the barrels. Several manufacturers go up to that 125 limit, but there is a growing number of barrels that are being filled with a lower proof.
As it turns out, a lower entry proof seems to produce better whiskey – but it is also more expensive.
Curious why the whiskey is better with a lower entry proof? I will explain the three primary reasons below.
The first one focusses on the premise, that the lower proof will make it easier for the liquid to dissolve the sugars in the wood. High-level this makes sense, as the water molecules are smaller than the alcohol (ethanol) molecules – and thus easier to penetrate the wood. I have done some research on exactly what goes on – and even though this is a nerdy post, a full explanation will be too boring.
The second one is (sort of) linked to the first one: As the lower-proof liquid is penetrating the wood, the water will dissolve some of the “phenolic” compounds. Once dissolved, they will start to oxidize – and some of the unwanted tough and tannic flavors in those compounds will start to recede. You can read a more about this in a great article that Fred Minnick wrote for Whiskey Advocate here: http://whiskyadvocate.com/secret-science-proof-and-barrels/
The third one is based on pure math; Adding more water in the beginning, means that you need to add much less water in the end – and you therefore have more of the “original” distillate left in the bottle. If you have not fallen asleep already, let me try to explain what is going on – and sorry for all the calculations!
Let’s say you decide to go down from the legal maximum of 125 proof to 103 proof, when you dilute the new whiskey that goes into the barrels. The new whiskey from the distillation process is probably around 140, so you will need to add around 15 gallons of water to get from 140 to 103. If you had decided to go for the maximum 125, you would only have to add a little more than 6 gallons of water to get from 140 to 125.
Initially, you would think “How can adding more water be better??” Hang in there and let’s fast forward e.g. six years. The proof in your barrel has now (most likely) increased from 103 to 110 – as proof almost always increases during the aging process. Had you gone with the maximum of 125 proof, it would probably have been around 135 proof, by now.
If your plan is to sell your whiskey at 90 proof, you would now have to add another 10 gallons to proof down from 110 to 90. In case you are doing the calculations yourself, I have worked under the assumption that there are only about 44 gallons left of the original 53 gallons, due to evaporation over the six years. Had you gone with the maximum 125 proof – that would now be up to 135 – you would need to add whooping 22½ gallons of water to cut it down from 135 to 90.
So …. the total amount of water you added in the entire process from the new whiskey left the distillation process at 140 proof, to the reduction to 103 proof into the barrel, to the increase to 110 proof during the six years, to the final reduction to 90 proof in the bottle – you had to add a total of 25 gallons of water (15 initially and 10 at the end). Had you instead decided to start at 125 proof, you would have needed 3½ gallons more (6 initially and 22½ at the end):
In conclusion: A low barrel entry proof is more expensive to make because it requires less water (and water is obviously less expensive than the distillate). Your whiskey is, therefore, less diluted – and that’s a good thing.
And then just one more thing, if you think about it: In the example above, 15 gallons of water spent six years in the barrel if you had selected 103 barrel entry proof and only 6 gallons had spent time in the barrel if you had gone for 125 barrel entry proof. So not only do you add less water – the water that is added is extra-aged ….
Phew … enough with all those calculations …. I think we all need a Bourbon.
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