On food and cooking the science and lore of the kitchen ( PDFDrive ) 1432

condenseandarecollectedasaseparate
liquid.
Theconcentratedalcoholicliquidisthen
modifiedinvariouswaysfor
consumption.Itmaybeflavoredwith
herbsorspices,oragedinwoodbarrels.
Thealcoholcontentisusuallyadjusted
withtheadditionofwaterbeforeit’s
bottledforsale.
TheDistillingProcessTheessentialprinciple
of distillation is a simple one: both alcohol
and aromatic substances are more volatile in
water than water itself, so they evaporate in
disproportionateamountsfromwineandbeer
andbecomeconcentratedinthevapor.Butit’s
not a simple matter to make a delicious
distilled alcohol, or even a drinkable one.
Yeast fermentation produces thousands of
volatile substances, and not all of them are
desirable. Some are unpleasant, and others,
notablymethanol,aredangerouslytoxic.


Selecting Desirable Volatiles Distillers must
therefore control the composition of the
distilled liquid. They do this by subdividing
thevaporintofractionsthataremoreandless
volatile, and collecting mainly the fraction
that is richest in alcohol. The fraction more
volatilethanalcohol,oftencalledthe“heads”
or “foreshots” because it evaporates earlier

than alcohol, includes toxic methanol, or
woodalcohol,andacetone.Thefractionthat’s
less volatile than alcohol, the “tails” or
“feints,” includes a host of aromatic
substances that are desirable. Among these
“congeners” (substances that accompany
alcohol) are esters, terpenes, and volatile
phenolics, along with some substances that
are desirable in limited amounts. The most
notableofthelatterarethe“higher”alcohols,
whose long, fat-like chains can give spirits a
full, almost oily body, but also contribute a
pronounced harsh flavor and unpleasant
aftereffects. They’re often calledfusel oils.