JOHNNY’S
ART & SCIENCE
of DISTILLATION
COLUMN
CHEMISTRY
of CUTS
WRITTEN BY JOHNNY JEFFERY
t
he biggest misconception, and the silliest myth, being spread yeast cell walls. All of these in combination, balanced through by distillers about cuts and the compounds in them is that the use of the still and any plate or rectification technology,
we make cuts to remove all the “bad stuff.” When we make a create the aroma, flavor and palate of the spirit. This is science heads or tails cut, we’re not removing all the bad stuff, we’re and art combined. adjusting the concentration of certain compounds that appear at
The late-comers to the party are high boilers. Their boiling points
higher concentrations than we would like in the finished product. are higher than ethanol but are in the same chemical families We have not removed them all, we have simply adjusted them. If as the low boilers. The bulk of these are alcohols with higher you remove them all you are making vodka.
molecular weight than ethanol: propanol, butanol, iso-butanol,
When running an alembic still the so-called heads and tails amyl alcohols (3,4, and 5 carbon alcohols). By themselves they compounds are coming out of the still and into the product are hideous — their descriptors include: band aid, chemical, for almost the entire run. Compounds found in the highest fuel, solvent. These sound like the kinds of things you’d want concentrations early on in the run (heads compounds), or low to get rid of completely, but the truth is that the standard of boilers as I’ll call them, include: acetaldehyde, acetone, ethyl identity for whiskey guarantees that you cannot. Unless whiskey acetate, methanol, and sometimes acrolein. These come off early is distilled to higher than 80% ABV, these compounds come because they boil at the lowest temps but they don’t all come through during the run with the hearts but like the low boilers, off early and then stop. At a certain point they fade into the this is not a bad thing. background and become part of the nose of the spirit.
High boiling compounds do a couple of important things.
To put this in perspective let’s use ethyl acetate. Not only is First, because they are high boilers they have the tendency to this ester formed in the barrel (ethanol combining with acetic stay on the palate creating a longer tasting experience before acid) during aging, becoming a necessary part of the familiar they evaporate. When their concentrations are in balance (and character of American whiskies, there’s actually a patent that particularly after they’ve had a few years to react into other was granted to a gentleman who figured out that if he added compounds and further increase in boiling temp) they stay on it to bourbon in the barrel, the bourbon was better and tasted the palate longer than ethanol will. Particularly with well-aged older to consumers than it actually was. This is one of the same spirits, you could never get the long lasting, bourbon chewing, compounds that you smell in fingernail polish remover.
tongue and palate coating experience of a beautifully aged spirit
The hearts cut of any spirit that is meant to have flavor is without high boilers. Second, and already mentioned, they are a rich and complex combination of fermentation byproducts, the substrate for aging chemistry. Whiskey, rum, or brandy that’s compounds extracted from grain and compounds extracted from going to sit in a barrel had better have some of these in there
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