Definitions

Question 1

Gravity

Answer 1

density of the wort, or a way of calculating the amount of dissolved substances, largely sugars that will be converted into alcohol (it is your first look at how alcoholic your final brew will

Question 2

Original Gravity (OG)

Answer 2

a ratio of density relative to pure water

Question 3

hydrometer

Answer 3

A weighted glass tube with a scale on the inside which stops at the relative density of the liquid being measure

Question 4

refractometer

Answer 4

Measures the original gravity only, based on the refractive properties of sugar. Alcohol distorts the reading

Question 5

Terminal gravity

Answer 5

how much gravity is left after the fermentation is finished and can be used to calculate the alcohol content of the finished beer (or wine, or cider)

Question 6

Alcohol by Volume (ABV)

Answer 6

percentage of ethanol in the finished beer

Question 7

Colour

Answer 7

The value of lightness/ darkness and red/ yellowness of a beer. Light/ dark measurements are acquired by measuring the beer in a spectrophotometer. Tristimulus are used to assess color

Question 8

Bitterness

Answer 8

the level of bitterness you taste when you drink beer. It is measured in bitterness units (BU) which relates to ppm isomerized alpha acid

Question 9

attenuation

Answer 9

measure how complete a fermentation process is

Question 10

wort

Answer 10

sugar and water mixture after malting

Question 11

fusal alcohols

Answer 11

alcohols that contain more the 2 carbons

Question 12

esters

Answer 12

cause a fruity flavour. Formed are formed in beer in the esterification of ethanol

Question 13

flavour maturation

Answer 13

The yeast remove undesirable compounds such as H2S, acetaldehyde, and diacetyl. This process is called purging

Question 14

Clarification

Answer 14

Green beer can contain 1 x 107 cells per mL. This would block your filter during filtration. Thus, the beer is allowed to settle so that yeast can be removed by sedimentation.

Question 15

Stabilization

Answer 15

To prevent a non-biological precipitate to form during storage. Stabilizers are added to remove the precursors of this precipitate

Question 16

Carbonation

Answer 16

CO2 is more soluble at reduced temperatures, so a top pressure of CO2 is maintained in conditioning tank

Question 17

Minimize Oxygen

Answer 17

Oxygen is low in green beer. If O2 finds its way back in, antioxidants are add

Question 18

Anaerobic Beer Spoiler

Answer 18

lactobacilli, cause turbidity, acid notes, and unwanted flavour

Question 19

Aerobic Beer Spoiler

Answer 19

primarily AAB, Acetobacter result in the production of acetic acid from ethanol

Question 20

sodium metabisulfate

Answer 20

1. traps oxygen that is in the wine

2. in Campden tablets, sterilize wine, cider, and beer

Question 21

stuck fermentations

Answer 21

a premature cessation (halt) of alcohol production in the fermentation

Question 22

diacetyl

Answer 22

odor compound with a buttery aroma.

• at low concentrations is described positively as “nutty” but at high concentrations is considered spoilage
• produced by both homo and hetero LAB

Question 23

slime and ropiness

Answer 23

bad and spoilage

Question 24

grape must

Answer 24

result of the crushing of grapes. contains a yeast flora similar in numbers and composition of those pre-harvest

Question 25

sulfur dioxide

Answer 25

added to kill natural species and allow wine specific Sc (which are resistant to sulfur dioxide) to carry out the fermentation.