Beer, Wine, Cider, Vinegar

Question 1

Beer

Answer 1

solution of water, CO2 and alcohol flavoured by carbs, proteins, minerals
-hops, yeast, grains

Question 2

Brewing

Answer 2

process of preparing beverages from grains that have sprouted, and their fermentation process

Question 3

how is gravity calculated?

Answer 3

using a hydrometer or refractomer

Question 4

What can alter the attenuation?

Answer 4

attenuation: how complete the fermentation process is

- sugar type, mashing method, composition of the wort, type of yeast

Question 5

high apparent attenuation vs low apparent attenuation

Answer 5

high: dry beer
low: sweet beer

Question 6

malting

Answer 6

the process where the grains soak in order for them to germinate.

Question 7

what is the purpose of malting

Answer 7

turn the food reserves in the grain into sugars convenient for use in the fermentation.

Question 8

what should the moisture content of the grains be at the start and during storage? (malting)

Answer 8

no higher than 20%

during drainage, CO2 and air are pumped through (CO2 promotes germination)

Question 9

milling

Answer 9

process where the malt is broken down into smaller, more fermentable sizes.

Question 10

mashing

Answer 10

ground malt is mixed with brewing water. A fermentable extract is produced that will support yeast.

Question 11

what are the steps to making beer

Answer 11

malting, milling, mashing, addition of hops, fermentation, post-fermentation additions

Question 12

Yeasts - beer. What conditions are preferable or negative?

Answer 12

too cold - lag period
too much - competition and stress
not enough - lag period
temp to high - fusal alcohols are produced

Question 13

can spores survive the brewing process?

Answer 13

yes, but not likely to germinate due to lack of nutrients.

Question 14

fermentation - phases

Answer 14

lag phase, exponential phase (high production of CO2 and ethanol)

Question 15

wine fermentation - phases

Answer 15

lab phase: a few hours
growth phase: (24-36hr)
stationary phase: long time

Question 16

malolactic fermentation

Answer 16

L-malic acid is converted to L-lactic acid and CO2

LAB: Oenococcus onesie

Question 17

what is special about wine yeast?

Answer 17

reciprocal translocation between chromosome 8 and 16

-direct relationship with the number of repeats and sulfite tolerance

Question 18

what can cause a stuck fermentation?

Answer 18

• Nutrient deficiency (nitrogen, vitamins, or minerals)
• Inhibitory Substances (acetic acid, lactic acid, excessive sulfur dioxide)
• Killer toxins (toxins produced by yeasts against other yeasts)
• pH to low (<3)
• Pesticides remain on grapes from field
• Temperature (too low at the beginning, or too high during the ferment

Question 19

malt vinegar

Answer 19

starch converted to maltose

maltose converted to ale, which is aged

Question 20

cider vinegar

Answer 20

made with apple juice through a double fermentation of alcohol and acetic acid in the same barrel.

Question 21

traditional balsamic vinegar

Answer 21

conversion of sugars to ethanol via yeast

at least 12 years of aging

Question 22

rice vinegar

Answer 22

produced by a static surface fermentation
final acidity is 10%
acetobacter is used (AAB)

Question 23

Colour

Answer 23

measured using spectrophotometer or tristimulus

Question 24

bitterness

Answer 24

measured in bitterness units, which relates to ppm isomerized alpha acid

Question 25

at what moisture content do grains begin to germinate?

Answer 25

42-46%

Question 26

are anaerobic or aerobic conditions favourable in beer?

Answer 26

yeast are both aerobic and anaerobic. anaerobic conditions are favourable because sugar uptake is increased

Question 27

why does production of alcohol by yeast slow and stop?

Answer 27

- Budding requires cell wall synthesis which cannot happen in anaerobic conditions, therefore eventually growth must cease - Eventually the level of ethanol present becomes toxic to yeast - When fermentation slows the yeast cells flocculate and sediment out (which causes growth to slow even further)

Question 28

esters

Answer 28

cause fruity flavour, are caused by the esterification of ethanol

Question 29

what are the 5 considerations during conditioning?

Answer 29

Flavour Maturation: The yeast remove undesirable compounds such as H2S, acetaldehyde, and diacetyl. This process is called purging. Clarification: 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. Stabilization: To prevent a non-biological precipitate to form during storage. Stabilizers are added to remove the precursors of this precipitate. Carbonation: CO2 is more soluble at reduced temperatures, so a top pressure of CO2 is maintained in conditioning tanks. Minimize Oxygen: Oxygen is low in green beer. If O2 finds its way back in, antioxidants are added

Question 30

are pathogens and issue with brewing?

Answer 30

nope. low pH, low nutrients, high ethanol content

Question 31

Anaerobic Beer Spoilers

Answer 31

LAB, turbidity, acid notes, and unwanted flavours

Question 32

Aerobic Beer Spoilers

Answer 32

are primarily AAB (Acetobacter and Gluconobacter) they will result in the oxidization of ethanol to acetic acid. There will be a “raft” of surface growth in the beer that will lead to generalize turbidity, and the infected beer may have a “ropiness” quality.

Question 33

grape must

Answer 33

At the start of the wine making process grapes are crushed and the grape must contains a yeast flora similar in numbers and composition of the grapes pre-harvest

Question 34

what is the role of sulfur dioxide in wine making?

Answer 34

Sulfur dioxide is added to kill natural species and allow wine specific Sc (which are resistant to sulfur dioxide) to carry out the fermentation, but despite the addition of sulfur dioxide several different species of yeast participate in the process -SO2 can inhibit the growth of microbes by rupturing disulfide bridges in proteins, and reactions with cofactors. It can also deaminate cytosine to uracil which increases the likely hood of fatal mutations

Question 35

campden tablet

Answer 35

1. used to sterilize. has very low levels of sodium metabisulfate, which traps oxygen and prevents it from harming the ferment. 2. eliminate free chlorine 3.

Question 36

what is a stuck fermentation?

Answer 36

when there is a premature cease in alcohol production.

Question 37

wine spoilage organisms:

Answer 37

LAB spoils some wine and adds flavour to others. | AAB is considered spoilage with off-flavours etc.

Question 38

what produces diacetyl?

Answer 38

homo and hetero LAB