Malt is processed from raw barley that is suitable for brewing.
It provides the starch that is converted into fermentable
sugars in brewing.
Sugar:
Sometimes
sugar is used as it provides additional source of fermentable
sugars that is required by yeast to produce alcohol.
Hops:
Although
a minor ingredient in beer, hops are used for their bittering,
flavouring and aroma-enhancing powers
Yeasts:
Yeasts
are responsible for converting fermentable sugars into alcohol
and carbon dioxide.
Water:
Water
adds to the flavour of the beer and composes more than 90%
of the beer.
1. Malt Milling
The objective of milling is to split the husk of the
malt kernel and expose the starchy content for the conversion
in the mashing process.
2. Mashing
Mashing is the process of converting starch from the
milled malt (known as the mash) into fermentable sugars
and amino acids to produce wort of the desired composition.
Mashing involves mixing milled malt with water at a
set temperature and volume to continue the biochemical
changes initiated during the malting process.
3. Wort Separation
After mashing, when all the starch has been broken down,
it is necessary to separate the liquid extract (wort)
from the solids to produce clear wort. The Lauter Tun
is equipped with a strainer which traps the solids and
allow the liquid to filter through.
4.
Wort Boiling
Following Lautering, the clear wort must be treated
by boiling it in the kettle for 90 minutes to sterilise
the wort, extract the bittering components from the
hops and allow flavour and colour to develop.
5. Wort Clarification
& Cooling
After boiling, the hot wort if pumped into a whirlpool
and the centrifugal effect separates the remaining solids
from the liquid. The clear hot wort is then cooled in
preparation for the addition of yeast and subsequent
fermentation. The principal changes that occur during
wort cooling are as follows:
1) Cooling the wort to yeast pitching temperature;
2) The formation and separation of malt protein materials;
and
3) Oxygenation of the wort to support yeasts growth.
6. Fermentation
Fermentation is the process by which fermentable sugars
are converted by yeasts into alcohol, carbon dioxide,
and numerous by-products. The by-products have a considerable
effect on the taste, aroma and other characteristic
properties of the beer. Fermentation is dependent upon
the composition of the wort, the yeasts, and fermentation
conditions.
7. Conditioning/Maturation
Following primary fermentation, the "green"
or immature beer is held at low temperatures for conditioning
and enhancement of its flavours. The
processes of conditioning are:
1) Flavour maturation,
2) Chill-proofing and Stabilizing (improves the clarity
of the finished beer) and
3) Carbonation.
8. Filtration
Final filtration is needed to remove residual yeasts,
other haze-forming materials, and micro-organisms in
order to achieve colloidal and microbiological stability.
9. Carbonation
The next major process, which takes place after filtration
and prior to packaging, is carbonation. Carbon Dioxide
contributes to the sparkling appearance, the mouth-feel
and it enhances the foaming potential of the beer.
10. Packaging
Once the final quality of the beer has been achieved,
it is ready for packaging. Glass bottles are filled
automatically and all oxygen removed to preserve the
high quality of the beer. Kegging is also another way
of packaging beer and it involves filling carbonated
beer into sterile stainless steel 30-litre kegs, using
micro-filters to remove any micro-organisms present.
10. Pasteurisation
After bottles have been filled and sealed, they are
passed under sprays of hot water on a conveyor. The
bottles are subjected to increasingly hot water until
the beer in the bottles reaches the pasteurisation temperature
(usually 60-62 Degrees Celcius). The bottles are then
gradually cooled with water until they are discharged
from the end of the parteuriser for labeling. The purpose
of pasteurisation is to arrest further microbial activities
in order to prolong the shelf-life of the beer.
After labeling, the bottles are
packed in crates of 24, which are then conveyed to the
Full Goods Store (FGS) for storage and distribution.
Guinness remains in the FGS for a minimum of 2 weeks
to allow the beer to mature in the bottle, whilst the
other beers can be distributed immediately.
Packaging capacities:
Kegging Machine -
30 kegs per hour
Glass Bottles - Line A
: 15,500 bottles per hour and Line B : 19,000 bottles per
hour
P.E.T. Bottling
Line - 5,000 1.5 litre bottles per hour
