lec 7 beer and brewing technology

Question 1

What is beer?

Answer 1

Alcohol containing beverage produced through
conversion of starch to (mainly) maltose which is
subsequently fermented

Question 2

what is the fundamental ingredient in beer brewing?

Answer 2

malt is a fundamental ingredient that provides fermentable sugars and contributes to the flavor, color, and body of the final beer.

Question 3

what is malt typically made of?

Answer 3

from cereal grains, with barley being the most common choice due to its high enzyme content, which is crucial for starch conversion during brewing.

Question 4

what is germination?

Answer 4

converting cereal grains, typically barley, into malt.

Cereal kernels (most commonly barley)
in which germination is initiated and
subsequently stopped
* Activation of enzymes
* Other cereals: wheat (oats and rye to a
lesser extent)

Question 5

what are the Most important enzymes in malt?

Answer 5

α-amylase and β-amylase -
maltose and dextrins
* Proteases –amino acids for the
yeast
* β-glucanase – reduce viscosity
during mashing, improve
filterability

Question 6

what is the Diastatic power?

Answer 6

the enzymatic activity of malted grains in converting starches into fermentable sugars during the mashing process. It indicates the ability of malt to produce enzymes, such as alpha-amylase and beta-amylase, which are essential for starch conversion.

Question 7

what is Caramellization and roasting is important for?

Answer 7

flavour and colour
* Reduces or eliminates enzymatic activity

Question 8

what is Speciality malts?

Answer 8

a minor part of the total malt used

specialty malts are used in smaller quantities and primarily contribute to the color, flavor, aroma, and mouthfeel of the finished beer.

Question 9

what are Adjuncts

Answer 9

Unlike specialty malts, which are primarily used for flavor and color, adjuncts are primarily used to increase fermentable sugars and influence the beer’s overall composition.

• they are Non-malted ingredients
• Cereals: maize (corn), rice etc. – as source of sugar
• Diastatic power in the total formulation becomes crucial –
  addition of enzymes (β-amylase)
• Sugar
• Roasted barley (flavour and colour)

Question 10

what role does water play as an ingredient in beer?

Answer 10

• Solvent and main ingredient
• Provides minerals for the yeast
• pH and minerals will affect enzyme activity and beer
  flavour
• Typical pH 5.2-5.5
• Hardness can influence flavour and enzyme activity
• Contaminants can cause off-flavours

Question 11

Malt crushing

Answer 11

• Faciliatate mashing
• Husks should be intact – facilitate extraction and draining (sparging, lautering)
• Particle size after crushing is crucial.

Question 12

what is mashing?

Answer 12

degradation of starch

Question 13

what are themost common type of mashing?

Answer 13

Most common: Infusion mashing
* Crushed malt is mixed with warm water
* Different temperature rests leads to optimal enzymatic
activity
* Which rests are used depend on the beer
* In some malts protein and β-glucan are already
considerably degraded (“highly converted” malts)

Question 14

what happens at Low T (63-65 °C) during mashing?

Answer 14

efficient degradation to maltose, smaller body (lager)

Question 15

what happens at High T (>65 °C) during mashing?

Answer 15

less efficient degradation, larger body (ale och stout)

Question 16

what is the optimal ph for mashing

Answer 16

Optimal pH=5,2-5,5
–>adjustement of water pH with acid or acidulated malt

Question 17

what is the Typical saccharification rest

Answer 17

60-90 min

Question 18

what happens at Too high T (approx. >80 °C) and/or too long time during mashing?

Answer 18

extraction of polyphenols

Question 19

what is Mash-out?

Answer 19

short time >74 °C to deactivate enzymes and
decrease mash viscosity

Question 20

what step is after mashing?

Answer 20

Draining and sparging

Question 21

what is sweet wort

Answer 21

Sweet wort is the liquid extracted from the mashing process during beer brewing. It is rich in fermentable sugars and other soluble compounds derived from malted grains

The mash is drained and sparged with water (70-77 °C)
–> sweet wort

Question 22

when does sparging stop?

Answer 22

when sufficent volume and/or the desired concentration of sugars has been obtained

Question 23

how is Wort strength measured

Answer 23

°Oechsle, °Plato (refractive
index) or ”gravity” (relative density)

Question 24

what functions does the boiling in beer brewing have?

Answer 24

Several functions
* Pasteurization
* Evaporation on unwanted aromas (e.g. dimethyl
sulphide)
* Precipitation of proteins –clarification
* Maillard reactions – colour
* Extraction of bitterness and flavour from hops!
* Clarification aids are often used – carrageenan
etc (forms complexes with proteins)

Question 25

what is hops?

Answer 25

Hop is a vine with cones containing aroma and flavour substances * α- and β-acids (humulones och lupulones) * Oils (hop flavour and aroma) * Sensitive to oxidation * Relatively expensive ingredient

Question 26

what happens with α-acids During the boil?

Answer 26

α-acids are isomerized--> bitterness

Question 27

what is involved in foam stability?

Answer 27

α-acids are involved in foam stabilty

Question 28

how is the hops affected during the boil?

Answer 28

* The extent of isomerization depends on boiling time * Long boiling evaporates aroma substances * Added at different times during the boil * Isomerized hop extracts

Question 29

what step is after the boil?

Answer 29

Fermentation and conditioning

Question 30

what happens during Fermentation and conditioning?

Answer 30

* Rapid cooling after boil * Oxygenation of wort * Addition of yeast * Conditioning (and sometimes secondary fermentation) * (Filtration) * (Pasteurization)

Question 31

what are Different types of yeast in beer?

Answer 31

* Saccharomyces cerevisiae -->Ale * Saccharomyces pastorianus (syn. carlsbergensis och uvarum) -->Lager * Brettanomyces --> ”wild yeast”, can ruin beer but desirable on some types of beer. * Some beers --> lactic acid bacteria

Question 32

what does the temp influence during fermentation?

Answer 32

Temperature has a strong influence on which flavours are generated

Question 33

What does higher temp during fermentation produce?

Answer 33

High T (>18 °C) gives higher production of esters, ethanol, higher alcohols (fusel alcohols), acetic aldehyde etc. (Typical for Ale, Stout etc.)

Question 34

What does low temp during fermentation produce?

Answer 34

Low T (<12 °C) lower production of flavour compunds  ”cleaner taste” (Lager)

Question 35

what happens when sugar is depleted during fermentation?

Answer 35

the yeast can metabolize other compounds which affects the taste

Question 36

Some common flavours generated by yeast

Answer 36

Acetic aldehyde -Green apple Fusel alcohols-Solvents, spirits Oraganic acids (acetic, malic, citric etc)- Sour Esters- Banana, raspberry, pear etc. Hydrogen sulphide-Rotten egg 2,3-butandione (diacetyl)-Butter scotch Glycerol- Sweet

Question 37

what are Some quality aspects of beer?

Answer 37

Microbial contamination * Staling – oxidation * Main limiting factor for beer shelf-life * Foaming and foam stablity * Gushing * Related to microbial contamination in the malt * Foam stabilizing compunds * Oxalates (beer stone) – nucleii for CO 2 * Lacing * Colloidal stability – chill haze formation * Proteins and polyphenols and more * Eliminated by filtration