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BEER CHEMISTRY 101 The
waitress asks, “Would you like something to drink?” I
reply, “Yes. I think I’ll
have a beer.” “What
kind would you like, sir?” Now
comes the fun part. Should
I order a light beer as opposed to a dark beer? Will a sweet and malty beer hit the spot?
Perhaps a light bodied, dry beer might best suit the entrée that I
am considering. Choice
is good. It keeps life
interesting. Thank God for
chemistry! That’s
right. It’s the
manipulation of chemistry that makes one beer distinctive from
another. Hold
on! No need to bolt!
No browbeating chemistry lecture lies ahead.
Promise. What follows
is mostly a brief FYI session. After
reading this article, some will desire to seek more details, some won’t. I only ask to be briefly indulged as I seek to gain a modicum
of social redemption for the ever-unpopular chemistry teacher by
connecting his/her craft to the ever-popular beverage called beer. Oh,
just one other thing before starting the minimally technical stuff.
What follows should demonstrate that the marriage of beer-related
information to chemical data from the periodic table is a rather natural
union. Beer is, in the final
analysis, only one of the innumerable manifestations of chemistry.
It just so happens that beer ranks among the highly appealing of
these manifestations. Water
is the main ingredient in all beers.
Accordingly, its chemistry can have a profound effect on the
finished product. The complex
mineral composition of the water around London renders the water
“hard.” The hardness of
the water plays a significant role in the brewing of the pale ales of
England. The pilsner style of
beer associated with central Europe, however, relies upon the water used
for brewing to be relatively free of dissolved minerals. Treated
water, such as water that has been chlorinated or that is alkaline,
presents problems to the brewer. Chlorination
can produce a medicinal taste or an undesirable odor. These are not endearing qualities for a beer to have.
Furthermore, alkalinity can (Heaven forbid!) interfere with
fermentation. The water’s
source (purity) must be an ever-present concern of the brew master. The
mashing procedure is also chemistry driven.
Lower mash temperatures and a pH of 5.0 render beers of drier
taste, less body and decreased malt character.
Higher mash temperatures and a pH of 5.7 produce beers that are
heavier bodied, sweeter and of a malty character.
Proper
boiling of the wort denatures molecules, causing them to precipitate out
of solution, clarifying the beer.
Furthermore, chemical conditions in the wort must be properly
controlled in order to promote proper fermentation.
Speaking
of fermentation, some by-products of this process can be troublesome if
not controlled. These
by-products have very low flavor thresholds allowing for small amounts
present in a beer to be very noticeable.
The pursuit of a quality beer requires the brewer to be ever
vigilant about the presence or the extent of presence of these
by-products. I
trust that the above was not too overbearing.
For those who would like more detail, I suggest that you consult an
essay titled A Brewer Uses Chemistry.
William R. Jenkins, who is the Package Production Manager at Pike
Place Brewery, wrote the essay. Mr.
Jenkins is also a chemist. The
essay appears in General Chemistry, second edition.
West Publishing Company is the publisher. Mr. Jenkins’ essay served as my principal source for the
technical descriptions concerning the brewing of beer as stated above. I
hope that having read this little “chemistry lesson” will produce a
favorable reaction among its readers.
Specifically, it would be nice if when one of you tips that next
glass of your favorite brew, you allow a millisecond for appreciative
reflection on the wonders of chemistry.
It would be even better if, upon seeing your old chemistry teacher
at the other end of the bar, you would point toward the old
“crumudgeon” and advise the barkeeper that “The bookish looking,
little bald guy’s tab is on me tonight.”
OK! So it wasn’t a
very subtle hint to any of my former students who might happen to read
this article.
Minimally Technical Glossary
mineral
= a unique inorganic (not animal or vegetable in origin) substance that
can be represented by a chemical formula water
= molecules consisting of two hydrogen atoms chemically bonded to a single
oxygen atom; often called the universal solvent hard
water = water containing miniscule particles in solution that interfere
with the lathering and cleansing properties of soap and that corrode metal solution
= commonly, the result of the dispersing of a substance in water solvent
= a substance throughout which another substance is dispersed in the
making of a solution (ex: water is the solvent; salt is the solute, i.e.,
the substance dispersed throughout the water) dissolved
= the description of the dispersed component of a solution precipitate
= here, a formerly dissolved substance made to separate from the solution
as a solid, ultimately falling to the bottom of the vessel chlorinated
= here, water in which chlorine has been dispersed (dissolved) alkaline
= a solution whose pH is above 7 acidic
= a solution whose pH is below 7 pH
= the measure of acidity or alkalinity of a solution fermentation
= the process whereby glucose is processed by yeast, in the absence of
oxygen, to produce ethanol (an alcohol) glucose
= a simple sugar yeast
= specific type of fungi used to ferment sugars to alcohol mash
= crushed or ground malt soaked in hot water for making wort malt
= water softened grain producing sprouts used for brewing wort
= liquid produced from malt and later fermented to produce beer denature
= here, to change the structure of a molecule by physical and/or chemical
means
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