Beer Brewing

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Beer Brewing

• Barley, hops, yeast and water

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Overview
Inputs
Brewhouse
Outputs
Preprocessing
Grind
Barley
Malt
Water
Spent grain
Mash
Filter
Lauter
Hops
Trub
Process
Boil
Yeast
Ferment
Filter
Yeast
Cold condition
Finished beer
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Overview
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Inputs

• Barley
• Highest quality standards
• Low protein preferable
• American barley is high in protein
• Other grains can be used, such as wheat, oats,
  rice, or corn but barley makes up the majority of
  the grist

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Inputs

• Water
• Hardness and alkalinity are important
• Low levels of contaminants, otherwise filtering
  is necessary
• More on this later

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Inputs

• Hops
• A herb, one of many that were traditionally used
  in beer making
• Can add bitterness, flavour or aroma, depending
  on when it is added to the boil
• Hop oils are concentrated in the flower
• Lots of different varieties from around the
  world, each with its own subtle flavours

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Inputs

• Yeast
• A single celled organism, it is responsible for
  transforming sugar into alcohol and other flavour
  compounds
• Two main types used in beer making
• Ale
• Ferments only above 18C
• Has a strong influence on flavour
• Lager
• Ferments at any temperature above freezing
• Ferments clean (small influence on flavour)
• Many different strains from around the world

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Preprocessing

• Malting
• Allow the barley seed to germinate
• Grow only enough to release the plants store of
  enzymes
• Kiln to kill the growing plant
• Polish to remove rootlet and shoot
• Roasting
• Different levels of roasting give different
  flavours
• Can be crystal or base malts depending on
  technique

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Preprocessing

• Water filtering
• Remove any unwanted contaminants
• Add salts to bring the profile into the range you
  want
• Soft water for light coloured beers
• Hard water for stouts
• Water chemistry is responsible for the unique
  beers that were developed in different regions of
  the world
• Stouts require very hard water
• Pilseners require very soft water

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Preprocessing

• Hops processing
• Hops are harvested, and processed at the farm, as
  the flowers need to be dried to preserve them
• Can be left as whole flowers, packed into plugs
  or pelletised
• Each has its advantages and disadvantages

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Overview
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Brewing

• First, the malt is ground so that water can get
  inside
• Crushed between rollers
• Then, it is soaked in water (mash)
• Water temperature is adjusted to activate
  different enzymes. There can be multiple
  temperature rests, or only a single rest to
  convert starch to sugar
• The liquid is then drained from the bottom of the
  tun lautering

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Brewing

• The sweet liquor is drained into the kettle,
  where it is boiled
• Hops are added at various times
• 60 minutes to go bitterness
• Bitter compounds are large and take time to
  dissolve
• 20 minutes to go flavour
• Flavour compounds are smaller, they take time to
  dissolve but evaporate over time
• 5 minutes to go aroma
• The smallest compounds, dissolve readily but also
  evaporate extremely easily

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Brewing

• The boiled wort is then drained from the
  kettle, through a chiller which cools it to the
  correct fermentation temperature
• Yeast is added
• Primary fermentation normally takes a week, and
  the yeast are consuming mainly the easy sugars
• The beer is then transferred to a second vessel,
  where the yeast start to consume the hard
  compounds

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Brewing

• Once fermentation is complete the beer can be
  filtered
• Large commercial breweries normally filter
• Some people dont like yeast
• Makes beer bright
• Can increase stability (shelf life)
• Smaller breweries often dont filter
• Beer will then age like wine
• Some like yeast flavour

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Brewing

• The beer is then cooled for cold-conditioning
• If it is a lager, the yeast can continue
  fermenting
• For all types of beer, tannins and other
  bad-tasting compounds drop out of solution,
  improving flavour

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Products

• Spent grain is normally fed to livestock
• Trub is the yeast, spent hops and other sediment
  from fermentation
• The yeast is often washed and reused

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Overview