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Manufacturing of Beer
Brewing is fundamentally a natural process. The art
and science of brewing lies in converting natural
food materials into a pure, pleasing beverage.
Although great strides have been made with the
techniques for achieving high-quality production,
beer today is still a beverage brewed from natural
products in a traditional way. Although the main
ingredients of beer have remained constant (water,
yeast, malt and hops), it is the precise recipe and
timing of the brew that gives one a different taste
from another. The production of beer is one of the
most closely supervised and controlled manufacturing
processes in our society. Apart from brewing company
expenditures on research and quality control
designed to achieve the highest standards of
uniformity and purity in the product, the production
of beer is also subject to regular inspection and
review by federal and provincial Health Departments.
Substances used in the brewing process are approved
by Health Canada. On average, a batch of beer will
take about 30 days to produce. To be more specific,
brewing takes nine and a half hours, while
fermentation and aging combined take between 21 and
35 days for ales and lagers respectively.
1. Water
Pure water is an essential ingredient in good beer
and brewers pay scrupulous attention to the source
and purification of their brewing water. The water
used in brewing is purified to rigidly-set
standards. If it does not have the proper calcium or
acidic content for maximum activity of the enzymes
in the mash, it must be brought up to that standard.
2. Malt
Barley is used to make brewers' malt. At the malting
companies, barley is soaked, germinated (sprouted),
then dried and/or kilned/roasted to arrest further
growth. During the period of controlled growth in
the malting plant, specific barley enzymes are
released to break down the membranes of the starch
cells that make up most of the kernel. But these are
internal changes only; apart from a slight change in
colour, the external characteristics remain
essentially unchanged. When the malt leaves a
malting plant, it still looks like barley.
In the brewery, the malt is screened and crushed
rather than ground to flour in order to keep the
husks as whole as possible. This process not only
prevents the extraction of undesirable materials
from the husks but also allows them to act as a
filter bed for separation of the liquid extract
formed during mashing.
3. Mashing
Malt is added to heated, purified water and, through
a carefully controlled time and temperature process,
the malt enzymes break down the starch to sugar and
the complex proteins of the malt to simpler nitrogen
compounds. Mashing takes place in a large, round
tank called a "mash mixer" or "mash tun" and
requires careful temperature control. At this point,
depending on the type of beer desired, the malt is
supplemented by starch from other cereals such as
corn, wheat or rice.
4. Lautering
The mash is transferred to a straining (or lautering)
vessel which is usually cylindrical with a slotted
false bottom two to five centimetres above the true
bottom. The liquid extract drains through the false
bottom and is run off to the brew kettle. This
extract, a sugar solution, is called "wort" but it
is not yet beer. Water is "sparged" (or sprayed)
though the grains to wash out as much of the extract
as possible. The "spent grains" are removed and sold
as cattle feed.
5. Boiling and Hopping
The brew kettle, a huge cauldron holding from 70 to
1,000 hectolitres and made of shiny copper or
stainless steel, is probably the most striking sight
in a brewery. It is fitted with coils or a jacketed
bottom for steam heating and is designed to boil the
wort under carefully-controlled conditions. Boiling,
which usually lasts about two hours, serves to
concentrate the wort to a desired specific gravity,
to sterilize it and to obtain the desired extract
from the hops. The hop resins contribute flavour,
aroma and bitterness to the brew. Once the hops have
flavoured the brew, they are removed. When
applicable, highly-fermentable syrup may be added to
the kettle. Undesirable protein substances that have
survived the journey from the mash mixer are
coagulated, leaving the wort clear.
6. Hop Separation and Cooling
After the beer has taken on the flavour of the hops,
the wort then proceeds to the "hot wort tank". It is
then cooled, usually in a simple-looking apparatus
called a "plate cooler". As the wort and a coolant
flow past each other on opposite sides of stainless
steel plates, the temperature of the wort drops from
boiling to about 10 to 15.5 °C, a drop of more than
65.6 °C, in a few seconds.
7. Fermentation
The wort is then moved to the fermenting vessels and
yeast, the guarded central mystery of ancient
brewer's art, is added. It is the yeast, which is a
living, single-cell fungi, that breaks down the
sugar in the wort to carbon dioxide and alcohol. It
also adds many beer-flavouring components. There are
many kinds of yeasts, but those used in making beer
belong to the genus saccharomyces. The brewer uses
two species of this genus. One yeast type, which
rises to the top of the liquid at the completion of
the fermentation process, is used in brewing ale and
stout. The other, which drops to the bottom of the
brewing vessel, is used in brewing lager.
In all modern breweries, elaborate precautions are
taken to ensure that the yeast remains pure and
unchanged. Through the use of pure yeast culture
plants, a particular beer flavour can be maintained
year after year. During fermentation, which lasts
about seven to 10 days, the yeast may multiply
six-fold and in the open-tank fermenters used for
brewing ale, a creamy, frothy head may be seen on
top of the brew. When the fermentation is complete,
the yeast is removed. Now, for the first time ,the
liquid is called beer.
8. Cellars
For one to three weeks, the beer is stored cold and
then filtered once or twice before it is ready for
bottling or "racking" into kegs.
9. Packaging
In the bottle shop of a brewery, returned empty
bottles go through washers in which they receive a
thorough cleaning. After washing, the bottles are
inspected electronically and visually and pass on to
the rotary filler. Some of these machines can fill
up to 1,200 bottles per minute. A "crowning"
machine, integrated with the filler, places caps on
the bottles. The filled bottles may then pass
through a "tunnel pasteurizer" (often 23 metres from
end to end and able to hold 15,000 bottles) where
the temperature of the beer is raised about 60 °C.
for a sufficient length of time to provide
biological stability, then cooled to room
temperature.
Emerging from the pasteurizer, the bottles are
inspected, labelled, placed in boxes, stacked on
pallets and carried by lift truck to the warehousing
areas to await shipment. Also in the bottle shop may
be the canning lines, where beer is packaged in cans
for shipment. Packaged beer may be heat-pasteurized
or micro-filtered, providing a shelf-life of up to
six months when properly stored. Draught beer, since
it is normally sold and consumed within a few weeks,
may not go through this process. The draught beer is
placed in sterilized kegs ready for shipment. |
