Spirits Production

Question 1

What is the aim of alcoholic fermentation?

Answer 1

To create alcohol and flavours

Question 2

What is the aim of distillation?

Answer 2

To concentrate and select some of the fractions from a fermented alcoholic liquid or solid.

Question 3

What is the aim of processing a raw material?

Answer 3

To create a sugary liquid (or solid) that has flavours from the raw material.

Question 4

What is the aim of post distillation operations?

Answer 4

To adjust the flavour, colour, sweetness and alcohol level of a spirit.

Question 5

Complete the statement: Starch is a complex carbohydrate composed of ________________ molecules.

Answer 5

Glucose

Question 6

How are Ester’s formed?

Answer 6

When a fatty acid reacts with an alcohol.

Question 7

What is produced when yeast metabolises sugar?

Answer 7

Primary outputs are Ethanol, Carbon dioxide and heat. Other outputs include Methanol, Fusel Alcohols, Esters, Fatty acids and sulfur compounds.

Question 8

What are Fructans?

Answer 8

Fructans are a group of complex carbohydrates made up of predominantly fructose.

Question 9

What are amylases?

Answer 9

Enzymes used to break up starches.

Question 10

What is stored in the endosperm of a grain?

Answer 10

Starch granules.

Question 11

Gelatinisation is the process of what?

Answer 11

Using water and heat to unravel starch granules and make them soluble.

Question 12

What does the cooking of grains achieve?

Answer 12

The heat breaks up the protein net in the endosperm and also gelatinises the starches.

Question 13

What is the optimal temperature for the gelatinisation of the starch in Barley and for enzyme efficiency during the mashing process?

Answer 13

63-64 c

Question 14

In context of distillation, what is vapour?

Answer 14

Ethanol and water in a mixture of gas and liquid droplets.

Question 15

What is a maillard reaction?

Answer 15

A reaction when a sugar reacts with an amino acid. The reactions speed up as temperature increases.

Question 16

List the five key functions of Oak maturation

Answer 16

INTERACTION WITH THE ENVIRONMENT
1.Evaporation
2.Concentration
3.Oxygen
INTERACTION WITH THE OAK
4.Colour and Aroma (additive)
5.Char (subtractive)

Question 17

Give four factors that may influence the effect of maturation in an oak vessel

Answer 17

Answer may include:
1. Species of Oak
2. Size ofcontainer
3. Age (i.e. virgin oak, 2nd fill etc..)
4. Previous content
5. Fill Strength
6. Temperature
7. Humidity
8. Time
9. Char or toast level

Question 18

What will happen to the alcohol content of a spirit stored in a barrel kept in hot, dry conditions? Explain why.

Answer 18

The alcohol content will rise over time. This is because water evaporates at a faster rate than ethanol in a drier environment.

Question 19

The cumulative effect of Reflux in a still is know as what?

Answer 19

Rectification

Question 20

Name the five columns (in order) typically found in a multi column system.

Answer 20

1. Stripping
2. Rectifying
3. Hydroselection
4. Rectifying
   5 De-methylising

Question 21

Describe the glucose to starch to glucose process.

Answer 21

1. Starch is formed when the plant bonds glucose molecules releasing water.
2. Starch Molecules are rolled into tight granules and stored in a protein net
3. The protein net is broken up by enzymes or heat (modification)
4. Heat is used unravel the starch granules (gelantinisation)
5. Enzymes react with the starch, breaking the bonds that bind the glucose molecules (enzymatic hydrolysis)

Question 22

Explain the primary difference between sequential and parallel fermentation.

Answer 22

In sequential fermentation, a sugary liquid is formed before alcoholic fermentation begins whereas in parallel fermentation the starches are converted to sugar concurrently with the fermentation.

Question 23

What effect does still height have on the distillate.

Answer 23

The greater the height of the still, the greater the temperature gradient and therefore the greater the amount of reflux.

Question 24

Why is malolactic fermentaion desirable for distillers of grape brandy?

Answer 24

Malic acid is a key nutrient for spoilage bacteria. By converting Malic acid to lactic acid, the distiller reduces the chance of spoilage whilst the wine is stored awaiting distllation.

Question 25

Aside from ethanol, CO2 and heat what other outputs do yeast create during alcoholic fermentation?

Answer 25

1. Methanol
2. Fusel alcohols
3. Fatty acids
4. Esters and other aromatic compounds
5. Sulfur compounds

Question 26

What is “cultured yeast”?

Answer 26

Desirable strains of yeast are identified and isolated and stored in specialist facilities. These cultured stains are then supplied to distillers in dried, cake or liquid form.

Question 27

What is the advantage of using cultured yeast?

Answer 27

The distiller can be certain that the yeast they use will be the same every time and provided the sugary liquid is kept the same, the results of fermentation should be consistent.

Question 28

In pot distillation, a lower heat input has what effect?

Answer 28

A lower heat input and slower flow rate allows for greater seperation of the fractions. The distiller can then more easily make cuts that exclude more of the group 1 and 3 fractions resulting in a cleaner and purer spirit.

Question 29

In what part of a barley grain are the Amalayse enzymes stored?

Answer 29

They are in the bran.

Question 30

What is the boiling point of pure ethanol?

Answer 30

78.3 c

Question 31

In normal distillation what abv is the azetrope of ethanol and water?

Answer 31

97.3%

Question 32

What is the function of the demethylising column and how does it work?

Answer 32

The demethylising column aims to remove methanol from the spirit. Methanol is at it’s most voltile at high ethanol concentrations close to the azetrope. In this column, the rectified spirit is gently boiled with injected stem which then dilutes the spirit. This allows the methanol to seperate out over the hieght of the still and be collected from the top of the still. The purified neutral spirit is collected frm the base of the still.

Question 33

Name four higher (fusel ) alcohols

Answer 33

1. Iso Amyl
2. Propanol
3. Butanol
4. Phenethyl

Question 34

What are fusel oils and what effect could high levels have on a spirit?

Answer 34

Fusel oils are a mixture of hugher alcohols, fatty acids and esters. Eleveated levels of these could give a spirit a coarse texture with unpleasant aromas.

Question 35

What are the two main reasons why few distillers use ambient yeast?

Answer 35

1. There is no guarantee that the right microorganisim will dominate the fermentation thus yielding unpredictable results in flavour, yield and duration.
2. These type of ferments typically take longer to start and thus allow more opportunity for spoilage orgaisms to poduce undesired effect.

Question 36

Explain the typical differences in the distillates when using a shell and tube type condeser versus a worm tub.

Answer 36

A shell and tube condenser presents more surface area to the vapour and liquid and thus more copper contact and opportunity for sulfur compounds to be removed. This type of condenser is said to produce a lighter cleaner stye versus the heavier notes produced by worm tub condensers.

Question 37

What do the concentrating effects of distillation have on a fermented beverage with regards to aromatic compounds?

Answer 37

With concentartion the aromatic compounds become more important to the liquid’s style and quality.

Question 38

How is Sucrose different or glucose or fructose?

Answer 38

Glucose and Fructose are monosaccharides created in the plant during photosynthesis whereas sucrose is made by bonding glucose with fructose to form a larger molecule (polysaccharide) after photosyntehsis.