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How Beer is Made
P r 4-5 persona duhen:
How Beer is Made
by Sara Doersam
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P rgatitja:
Beer making dates back to 5,000 BC when yeast was discovered
fermenting in a sugar-water mixture. The yeast consumes the
sugar for its own energy and growth, and the primary byproducts
are ethyl alcohol and carbon dioxide. Wine is made when yeast
consumes the natural sugars in fruit such as grapes, and beer
is made when yeast consumes the sugar derived from grain.
The naturally occurring starch found in grain must be
converted into sugar before yeast can consume it.
Thus, beer making is a more complex art than wine making.
Making beer can be broken down into two separate processes
-- malting and brewing --
usually performed by two separate businesses.
Malting is the processing and preparation of grains
for brewing and takes years of training and experience
to master. Malting begins by soaking grain, usually barley,
in water long enough to begin germination or sprouting.
At the same time, enzymes are developing which break
down starches to sugars. The grain is then heated in
a large oven, called a kiln, which arrests germination
and stops the growth of the grain. Other grains, such
as wheat, rye, and oats can be malted, and many
maltsters sell malted wheat which is commonly
used in several specialty styles of beer.
Most homebrewers do not make their own malt because
it takes one to two weeks, requires close monitoring
and much work, and frequently renders inconsistent
results. The two most common methods of malting are
the traditional floor malting method, where grain is
literally spread across the floor to germinate, and
pneumatic malting, most common today, where the
environment is strictly controlled inside tanks
or drums. Maltsters can malt grains for a wide
variety of different types of malt, each offering
a different flavor and character.
Beer has four main ingredients
-- malt, water, yeast, and hops --
and it can be as simple or technically
challenging to brew, as down home cooking
is compared to gourmet cuisine. Each ingredient
has its own equally important role to play in
the production of beer.
To brew beer, the brewer begins by weighing the
appropriate amount of grain for his recipe.
He then mills his malt in a malt mill which
cracks his grain. In commercial operations,
the milled malt drops into a grist case which
has a valve at the bottom which allows the
grain to drop through a chute into the mash
tun. Usually homebrewers simply collect
their milled grain in a clean container
and dump it into their mash tun. The mash
tun is a large vessel, usually made of copper
or stainless steel, that has a screen-like
false bottom for straining your mash later.
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Mash is a thin mixture of grains and hot water.
Mashing is the process of heating grains mixed
with water at controlled temperatures for designated
periods of time to activate enzyme activity that
converts starches to fermentable sugars. Converting
starches to sugars is called saccharification.
There are three common mashing methods. Infusion
mashing is the simplest because it involves only
one temperature throughout the mashing process.
Step infusion mashing is basically infusion mashing
with one or two temperature increases during mashing.
And decoction mashing, most commonly used for lager
style beers, is the most complex method because part
of the mash is removed and boiled, then reintroduced.
Once mashing is completed, the brewer must separate the
sugar-water, called wort, from the spent grain husks.
He does this by sparging or rinsing the spent grains
with hot water to extract as much sugar from the grains
as possible. The grain husks act as a filter bed on the
false bottom of the mash tun. Commercial brewers usually
do their sparging in a lauter tun. After the wort is
collected in the brew kettle, it is boiled for one to two hours.
The boil is a critical step in the brewing process because
it is at this step that hops, the aromatic flowers of hop
vines, are added. Hops impart aroma, flavor, and bitterness
to beer, which balances the sweetness of the wort.
To extract the bitter resins from hops they must be boiled,
and usually hops are added at various stages of the boil
to extract bitterness or impart aroma or flavor.
When the boil is completed, the hot wort is transferred to a
heat exchanger or wort chiller which rapidly drops the
temperature of the wort to about 80 degrees
-- fermentation temperature.
As the tepid wort exits the wort chiller, it goes into a
fermenter where yeast is added. Most homebrewers us a
large glass called a carboy or stainless steel kegs for
fermenting, but commercial brewers use huge stainless
steel cylindrical conical tanks for fermenting.
The main genus of yeast used by brewers is Saccharomyces,
and the species used to make ales is a top fermenting
strain called cerevisiae, while the species used to make
lagers is a bottom fermenting strain called uvarum.
The type of yeast used during fermentation determines
whether a beer is an ale or a lager.
The yeast sets to work eating the malt sugar and expelling
alcohol and carbon dioxide. This usually takes three to
seven days and is referred to as primary fermentation.
Homebrewers then rack or transfer the beer off of the
yeast bed and into a secondary fermentation vessel,
whereas commercial brewers drain the yeast that has
collected out of the bottom of the tank.
If lagering, the beer may remain in cold storage for
several weeks or for a shorter period and in warmer
temperatures if brewing an ale. During the secondary
fermentation, the yeast precipitates out of suspension,
carbonation develops, and the beer matures.
Finally, the homebrewer is ready to bottle or keg his beer
for serving, while the commercial brewer may filter the beer
to make it bright and clear before kegging, bottling, or
transferring it into a serving tank. Homebrewing is one
of the fastest growing hobbies. If you can follow a recipe,
you too can brew.
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