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Bottom-fermentation
brewing process
Ingredients
Brewing water
The brewing water for traditional pilsner has very low mineral content. For other types of
beer, the brewing water has a higher salt content.
Malt
Pale malts with a low protein content. Quality malt is made from summer barley. Winter
barley has a thicker husk, contains more tannin and gives the beer a sour, stale taste.
Rice or maize
These do not contain any proteins and are used to lower the protein content in malt,
which is sometimes too high. The German “Reinheitsgebot” (beer purity law) does not
permit the use of maize or rice, which sometimes results in beers that have much too
much bite or which are not as refreshing.
Hops
Bitter hopping increases the digestibility and thirst-quenching qualities of a beer, pro-
vided that the bitterness does not cause a sour taste. The choice of hop variety, the
quantity used and the time when it is added to the brewing boiler play a part in determin-
ing the flavour and aroma profile: bitter hopping is carried out at the start of boiling and
aroma hopping at the end.
Fermentation process
A yeast strain selected from the bottom-fermenting species known as Saccharoymyces
carlsbergensis, which is active at low temperatures (0°C to 10°C), is used to ferment
the brew. Bottom-fermenting yeasts, originating from the Czech Republic, remain active
at these low temperatures, unlike bacteria. Bottom fermentation was therefore a good
method for brewing beers that would not turn sour.
Maturation
Maturation of bottom-fermentation beers occurs at 0°C in a maturation (lagering) tank.
At 0°C the bottom-fermenting yeasts remain active and continue to convert sugar into
alcohol, so that, depending on the pressure in the maturation tank, the carbon dioxide
content increases to approximately 5 g CO
2
/l.
Acidity
pH 4.2.
Carbon dioxide content (CO
2
)
• Keg conditioning 4.7 g CO
2
/l
• Bottle conditioning 5.7 g CO
2
/l
02.3
PALM BREWERIES
BOTTOM-FERMENTATION BREWING PROCESS
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Masterclass
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