14: Beverage Processing

Question 1

What is the general definition of alcoholic beverage?

Answer 1

• A liquid containing > 0.5% ethanol by volume

Question 2

Describe the process of beer fermentation.

Answer 2

Making the wort:
1. Malting: Grains are steeped, germinated and kilned.
2. Milling: The germinated grains is crushed to release enzymes
3. Mashing: Infusion or decoction mashing to extract fermentable sugars from the grain.

Preparing the wort
4. Wort separation: Filtration to remove insoluble solids from the wort
5. Wort boiling: Functions to extract & isomerize hops components, inactivate MOs and enzymes, remove undesirable aroma, form aroma & flavor.
6. Wort clarification: Sedimentation or centrifugation to remove spent hops
7. Wort Cooling and aeration: Promote aerobic CHO catabolism and prepare wort for yeast fermentation

Fermentation:
8 Primary fermentation: Addition of yeast to start alcoholic fermentation
9 Maturation and conditioning: Storage at oxygen free tank
10. Clarification and stabilization: Removal of yeast through centrifugation of filtration. Pasteurization to kill yeast.

Question 3

Describe malolactic fermentation.

Answer 3

Malolactic fermentation is a secondary fermentation process that occurs after primary (alcoholic) fermentation. It involves to use of bacteria (Oenococcus oeni) to convert malic acid into lactic acid. Malolactic fermentation contributes to flavor and aroma due to the production of diacetyl and acetaldehyde.

Question 4

Describe the processing step of fruit juices.

Answer 4

1. Raw material selection
2. Juice extraction
3. Post extraction treatments (Debittering, clarification & Pasteurization)
4. Juice concentration (Vacuum concentration to remove water and volatiles)
5. Packaging

Question 5

Describe the post-extraction treatments in fruit juices.

Answer 5

Debittering: Addition of styrene divinylbenzene in citrus
Clarification: Addition of pectinase to remove cloudiness
Pasteurization: FDA - Juice must be treated to achieve 5 logs reduction of most resistant pathogens. (Thermal/non-thermal pasteurization)

Question 6

Why are premium fruit juices often packaged in glass rather than plastic?

Answer 6

• Even though glass is more expensive, it provides the maximum preservation of flavors and aromas of fruit juices

Disadvantage of plastics:
- Adsorption of flavor compounds to packaging material
- Migration of components of packaging materials to the juice
- Gas and vapor permeable
- 50% lower shelf-life.

Question 7

What is one strategy to prevent oxidation during storage of fruit juice?

Answer 7

• Deaeration to remove dissolved oxygen before packaging.

Question 8

Describe the two main processes for the production of whiskey.

Answer 8

Distillation: A process to increase ethanol content
First distillation: The fermented wash is distilled. Ethanol vaporizes and condenses when it reaches to the worm to produce low wine.
Second distillation: Low wine is redistilled in a pot still to further purify and concentrate the alcohol. First distillate (Heads), second distillate (Hearts) and third distillate (tails) are produced. The hearts are transferred into barrels for aging. Heads and tails are either redistilled or discarded.

Maturation in wooden casks.