Brewing stages summary
- Created by: GladyGartland
- Created on: 26-02-22 15:50
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- Brewing
- Malting (1)
- Malt = source of lipid, proteins and carbs
- Involves: Steeping, germinating, kilning, roasting
- Different categories of malt: Crystal/ Caramel/ Chocolate / Roasted
- Purpose = to make it easier to extract nutrients from inside the grain
- Activates necessary enzymes for conversion of starch to sugar
- Germination produces alpha and beta amylases which are required for mashing
- Germination is then halted by killning
- Germination produces alpha and beta amylases which are required for mashing
- Process:
- Drying
- Grains dried to maximise germination ability. They then have a low moisture content and are stored
- Steeping
- Takes 48h
- Wets and aerates the grains
- Germination
- Produces enzymes and starts to break down the starch stored within barley
- Takes 3-5 days and is terminated by heating
- Alpha and beta amylase enzymes speed up the hydrolysis of amylose and amylopectin to sugars
- Produces enzymes and starts to break down the starch stored within barley
- Kilning
- Kilning makes grains friable, lowers moisture content and stabilises grains
- Increases colour and flavour (Maillard reaction)
- Reduces grain moisture and stops germination process
- But starch and brewing enzymes remain as long as not roasted or kilned at too high a temp
- Drying
- Mashing (2)
- Crushed grains mixed with water to form a porridge-like mixture (Mash)
- Mineral balance and pH of the water is very important
- Malt and other starches are transformed into sugars, proteins
- Stach is converted to sugar by alpha and beta amylase
- Mashable adjuncts = additional sources of malted or unmalted starch
- Malt bill = amount of each malt and mashable adjunct added
- Aim:
- Convert starches to fermentable sugars
- Recover as much sugar as possible
- Flavour and colour extraction from the malts
- Following mashing the grains are sparged to ensure the sugars have been transferred
- Crushed grains mixed with water to form a porridge-like mixture (Mash)
- Hops and boiling (3)
- Hop functions
- Preserve beer
- Counter malt sweetness with bitterness
- Provide aroma and flavour
- Hops are dried - at temps of less than 71 degrees
- Dried hops are crushed and pressed into pellets or compacted as dry cones and vacuum sealed in foil bags
- This proects alpha acids from oxygen and exposure to light
- Dried hops are crushed and pressed into pellets or compacted as dry cones and vacuum sealed in foil bags
- Hops are classed as bittering, aroma or both bittering and aroma
- Hops are quantified by their content of alpha acids
- Bitterness is the result of isomerisation in a-acids
- Isomerization is the small change in chemistry of a-acids that increases their water solubility and leads to bitterness
- Hops contain resins (a-acids and b-acids) and essential oils
- a acids are important for bitter taste
- Essential oils are the aroma compounds
- Hop functions
- Fermentation and conditioning (4)
- Yeast = most important ingredient in brewing
- Produces ethanol - makes beer alcoholic
- Different type of yeast for specific beer
- Different yeasts give different flavours
- These flavours come from the esters produced during yeast metabolism
- Phenols are flavour compound
- Different yeasts give different flavours
- Products of fermentation: Ethanol, higher alcohols, organic acids, esters, aldehydes, ketones
- Sterilisation is key - unwanted microorganisms could grown and compete with yeast
- Ensure wort has enough energy, nitrogen, vitamins and minerals, oxygen and water for yeast. also needs to be the correct temperature
- Life cycle
- Lag phase - yeast begins to take in vitamins and minerals - yeast makes enzymes for growth- oxygen rapidly absorbed
- Growth phase Yeast uses oxygen and nutrients to grow logarithmically
- Fermentation phase - Once no oxygen, yeast converts simple sugars to ethanol and CO2
- Sedimentation is the final stage. Yeast forms into a large mass that sinks or rises up
- Lagers = yeast sinks to bottom
- Ales = yeast rises to the top
- Fermentation is stopped by chilling the beer
- After fermentation , the beer is clarified and then conditioned in casks, bottles or kegs
- Beer conditioning: secondary fermentation and carbonation - increases shelf life and stabilizes beer
- Flavour/aroma change, addition of colour/flavour, longer beer is stored the smoother it will be
- Yeast = most important ingredient in brewing
- Malting (1)
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