Week 1: Tasting, alcoholic fermentation and the principles of distillation

Question 1

What are the two key nutrients required by yeast?

Answer 1

Sugars and nitrogen.

Question 2

What are the three direct outputs of the yeast’s metabolism of sugar?

Answer 2

Ethanol, carbon dioxide and heat.

Question 3

List five key yeast outputs not derived from the metabolism of sugar?

Answer 3

Methanol, fusel alcohols, esters, fatty acids, sulfur compounds.

Question 4

What are the two approaches to creating a sugary liquid and carrying out fermentation that distillers can take?

Answer 4

Sequential and parallel fermentation.

Question 5

What are fatty acids?

Answer 5

Acids made by yeast in the fermentation process.

Question 6

What are esters?

Answer 6

Compounds formed when fatty acids react with alcohols. They commonly have fruity aromas

Question 7

What are cultured yeast?

Answer 7

Yeast strains that have been identified, isolated and multiplied

Question 8

What are ambient/wild yeast?

Answer 8

Yeast in the air and on the surfaces of a distillery.

Question 9

What is the name of the process undertaken by lactic acid bacteria during which malic acid is converted into lactic acid?

Answer 9

Malolactic conversion.

Question 10

What are the 3 types of sugar?

Answer 10

Fructose Glucose Sucrose

Question 11

What is sucrose made of?

Answer 11

Fructose + glucose

Question 12

What are the 2 plant’s purposes for making sugar?

Answer 12

Using it as energy Building structure (with other nutrients)

Question 13

Most common fruits to be grown for spirits?

Answer 13

Apple, pears, grapes

Question 14

How are called the leftover skins and stalks from winemaking?

Answer 14

Pomace

Question 15

What are the 3 spirits made from pure sugar cane?

Answer 15

Rhum agricole, Cachaca, Kokotu Soshu

Question 16

What is “modification” in a grain?

Answer 16

Releasing the starch granules from the protein net

Question 17

What is “gelatinization”?

Answer 17

Solubilization of the starch granules with the help of water/heat

Question 18

How is called the break of the weak bond between glucose molecules?

Answer 18

Enzymatic Hydrolysis

Question 19

What is Kilning?

Answer 19

Process by which the germinated grain is dried and heated

Question 20

How do you call the milled malted barley?

Answer 20

Grist

Question 21

What happens during malting?

Answer 21

Modification and enzyme release

Question 22

What is mashing?

Answer 22

soaking grist in water (63°-64°) to allow gelatinization and enzymatic hydrolysis

Question 23

How long does mashing take?

Answer 23

1 hour

Question 24

How do you call spraying (twice) the solids filtered out to extract last bits of starch/sugars?

Answer 24

Sparging

Question 25

What is a wort?

Answer 25

The sugary liquid ready to be fermented

Question 26

What do we call a "distillers malt"?

Answer 26

A malt pale in colour caused by the low temp at kilning: preserves starches and enzymes for a maximum potential alcohol produced

Question 27

What do we call a "specialty malts"?

Answer 27

Malt receiving more heat during malting creating darker colored grains leading to heavier flavors

Question 28

What country accepts Exogenous enzymes for its whiskey?

Answer 28

America

Question 29

What is a fructan?

Answer 29

A complex carbohydrates made predominantly with fructose, especially found in agave

Question 30

What are the 2 advantages yeasts have over other microbes?

Answer 30

They survive in acidic environments They produce alcohol that keeps other microbes away

Question 31

What is the temperature operational range of yeasts?

Answer 31

10°C - 30°C

Question 32

What is the time range for a full fermentation?

Answer 32

24h to 1 week

Question 33

What are the two main roles of bacterias

Answer 33

Malolactic conversion Flavour creation

Question 34

What is reflux?

Answer 34

Heat exchange between droplets and gas tends to concentrate ethanol in gas and water in droplets. This effect over time is called rectification

Question 35

What is an "Azeotrop mixture"?

Answer 35

A liquid that reached a point when its droplets and gas have the same water/alcohol composition (97.3% abv)

Question 36

What is the composition of Group 1 fraction?

Answer 36

Methanol and others compounds (Unpleasant, solventy, shooting and painful for the nose)

Question 37

What is the composition of Group 2 fraction?

Answer 37

Ethanol mainly plus other fractions

Question 38

What is the composition of Group 3 fraction?

Answer 38

Fusel alcohol (plastic, feet, cheese aromas)

Question 39

What is the composition of Group 4 fraction?

Answer 39

Liquid to heavy to boil and never leaves the still. Generally acidic.

Question 40

On a higher still, do we get more or less reflux?

Answer 40

More, leading to a softer spirits with less group 3

Question 41

Do we get more or less reflux with a hotter heat input?

Answer 41

Less

Question 42

What is the role of Dephlegmator/head condensers

Answer 42

To manage temperature at the top of the still. Allow lighter or heavier fractions to pass through

Question 43

What is the Maillard reaction?

Answer 43

Caramelization/burning reaction happening when a sugar reacts with an amino acid. These reactions can take place in a still creating new flavours.

Question 44

Would distilled wines on lees get more or less Maillard reaction?

Answer 44

More

Question 45

What is the main chemical property of copper

Answer 45

It neutralizes sulfur

Question 46

What are the main purpose of the first pot distillation?

Answer 46

Removing water Discarding group 4 fractions

Question 47

What are the two principal aims of distillation?

Answer 47

Concentration and selection

Question 48

What is the name of the mixture of gas and tiny liquid droplets that rises up from a boiling liquid?

Answer 48

Vapour

Question 49

What is the boiling point of pure ethanol at standard atmospheric pressure?

Answer 49

78.3°C (173°F)

Question 50

What is rectification?

Answer 50

The cumulative effect of reflux. In distillation this is used to refer to the increasing level of ethanol in the vapour. A spirit that is distilled to a higher abv than another one is said to be 'more highly rectified'.

Question 51

How is the boiling point of Group 4 fractions compared to the boiling point of fractions in other groups?

Answer 51

The boiling point of these fractions is very high and they do not come over during distillation.

Question 52

What type of molecules have very pronounced, unpleasant aromas, even at relatively low levels of concentration, and cannot be easily separated from a spirit using cuts?

Answer 52

Sulfur-containing molecules.

Question 53

Name two materials are used in the construction of stills to manage the levels of sulfur-containing molecules?

Answer 53

Copper and clay.

Question 54

What is the boiling point of pure water at standard atmospheric pressure?

Answer 54

100°C (212°F).

Question 55

List 3 ways of managing reflux

Answer 55

Manage intensity of the boil Use of plates Use of dephlegmators

Question 56

What is the role of a sugar seed crystal?

Answer 56

To act as an anchor point for sucrose to crystallise

Question 57

What are the two aimes of cooking grains (other than barley)

Answer 57

Breaking the protein net and genalinisation