[As I’ve learned since through performing maturation experiments and reading a lot of journal articles, there are lots of flaws with my theory of what barrels contribute but you can still use the idea to create a very accurate barrel essence to add to other finished spirits]
After dissecting many spirits, I’ve come to realize that the vast majority of sensory attributes that a barrel contributes to a spirit are not volatile at the boiling points of ethanol and water [this fails to account for the significance of the angel’s share]. What this means is that we can remove the volatile constituents and end up with dried barrel essence. We can then introduce a solvent such as an un-aged fruit brandy or aromatic bitters and synthesize the character of barrel aging by having the perfect ratios of non-volatile compounds.
Vacuum reduction is a great tool for reducing a barrel aged spirit such as bourbon down to a dried powder because it reduces the boiling point of water enough that the flavor compounds will be as un-effected by heat as possible during evaporation (no process volatiles). My vacuum reduction rig is a Comeau vacuum aspirator (acquired for $75!) attached to a vacuum flask ($15) heated by a hot plate (a stove on low with a double boiler substitutes well). A double boiler always needs to be used because when you run out of water, the solids will scorch instantly. If your solids clump when you try and reconstitute them, they likely got scorched.
The cost of this process is essentially the cost in bourbon of the volume you want to artificially age. For example one ounce of bourbon is sacrificed for every one ounce of peach brandy you want to treat. An ounce of bourbon from a handle of Evan Williams costs about fifty cents.
For the proof of concept, 100ml of Old Granddad was reduced to powder and then the barrel essence was reconstituted with Kuchan brand Indian Blood Peach brandy. The results are very impressive with the un-aged spirit tasting very much aged. I never really enjoyed the un-aged peach brandy previously, because it seemed to resemble bubble gum, but the barrel essence seems to add attributes that push the ordinary into the extraordinary.
And this is all legal…! People are willing to spend tons of money reducing Campari to powder to rim a glass. This is significantly cheaper (after you spent $100 on some used lab equipment) and probably much more interesting on a sensory level.
[I’ve used this technique quite a bit, liters at a time, and have settled upon using an excalibur food dehydrator over a vacuum reduction rig. I’ve also digested quite a few brilliant journal articles on aging. This technique is a great predictive tool for distilleries doing new product development but you cannot be naive about the results and need to know how they differ from the real deal. A new make white dog, for example, would not be instantly aged and rather would require months to calm down and come to equilibrium. No angel’s share would be accounted for either. All in all, the results are better than any other fake aging technique and can be done affordably and accurately in volumes as small as 2 oz.]