Off Flavors

Question 1

Normally reduced to ethanol during fermentation

OXIDATION of finished beer may reverse this

Answer 1

Acetaldehyde

Question 2

Present in green beer

Answer 2

Acetaldehyde

Question 3

Bacterial spoilage Zymomonas or Acetobacter

Answer 3

Acetaldehyde

Question 4

Can taste in Budweiser due to beechwood chips

Answer 4

Acetaldehyde

Question 5

Bitterness acceptable in

Answer 5

HEAVILY HOPPED
IPA
American Barleywine

ROASTED NOTES
American Porter
Imperial Stout

HIGH SULFATE
British Bitters
English IPA
German Pils

Question 6

Body primarily determined by what 2 things

Answer 6

Dextrins

Medium body proteins

Question 7

Low dextrins caused by (3)

Answer 7

1. Low saccharification temps
2. Excessive completely fermentable adjuncts
3. Highly attenuation yeast strains

Question 8

Low protein level caused by (2)

Answer 8

1. Excessively short or long protein rest

2. Step temperature too high or low

Question 9

High alcohol affect on body

Answer 9

Lightens apparent body

Question 10

High carbonation affect on body

Answer 10

Decreases sensation of fullness

Question 11

Remedy for light body

Answer 11

1. Add dextrin malt
2. Add UNMALTED flaked grains
   
   • barley
   • oats
   • wheat

Question 12

Light body appropriate in (2)

Answer 12

1. American Light Lagers

2. Lambics

Question 13

Cheesy from ? compound

Answer 13

Isovaleric acid

Question 14

Sensory threshold for isovaleric acid

Answer 14

Huge differences in ability to sense

Question 15

Isovaleric acid causes (3)

Answer 15

1. Old hops
2. Hops improperly dried or stored high temps with oxygen
3. Brettanomyces

Question 16

Describe oxidation process for cheesy off flavor

Answer 16

Isovaleryl group removed from humulene alpha acid and becomes flavor activated

Question 17

Isovaleric ok in (3)

Answer 17

1. European Sour Ales
   
   • NOT Oud Bruin
2. English Old Ales
3. American Wild Ales

Question 18

Often mistaken for diacetyl

Answer 18

Caramel

Question 19

Yeast normally reduce diacetyl to

Answer 19

Diols

Question 20

Causes of diacetyl (5)

Answer 20

1. Premature removal yeast
2. Exposing wort to O2 during fermentation
   3 Low FAN levels
3. Yeast mutation
4. Lactic acid bacteria
   
   • Pedicococcus damnosus

Question 21

High fermentation temps promote formation or elimination of diacetyl?

Answer 21

Both

Question 22

Diacetyl rest temp

Answer 22

60-65°F

15-18°C

Question 23

Besides diacetyl rest what else can eliminate diacetyl

Answer 23

Krausening

Question 24

Diacetyl ok in what styles (5)

Answer 24

1. Czech Lagers
2. English Bitters
3. Brown and Dark British Beer
4. Irish Red Ale
5. Kellerbier

Question 25

Shellfish

Answer 25

DMS

Question 26

Aroma and taste of cooked veggies

Answer 26

DMS

Question 27

DMS produced by what rxn

Answer 27

Heat induced conversion of SMM | - S-methyl-methionine

Question 28

Causes of DMS (4)

Answer 28

1. Poor boil 2. Cool fermentation 3. Wild yeast or Zymomonas bacteria 4. Pilsner malt

Question 29

DMS appropriate in

Answer 29

Pilsner based Lagers - American Light Lagers - Classic American Pilsners Never Ales - exception CREAM ALE

Question 30

Esters formed by what rxn

Answer 30

Alcohol + organic acid

Question 31

Esters due to (6)

Answer 31

1. Yeast strain 2. High fermentation temp 3. High gravity wort 4. Metabolism of FATTY ACIDS in trub 5. Low pitch rate 6. Low wort aeration

Question 32

Most prevalent ester

Answer 32

Ethyl acetate | Nail polish remover

Question 33

3 most common perceived esters

Answer 33

1. Isoamyl-acetate ( BANANA) 2. Ethyl butyrate (tropical fruit bubble gum) 3. Ethyl hexanoate (RED APPLES)

Question 34

Fruity from hops comes from ?

Answer 34

Alcohols | Not esters

Question 35

Fresh cut grass or green leaves from what chemical class

Answer 35

ALDEHYDES hexanal and heptanal

Question 36

Grassy causes (2)

Answer 36

1. Oxidation of alcohols in finished beer | 2. Improperly stored malt or hops (MOIST)

Question 37

Grassy ok in (3)

Answer 37

1. English IPA 2. American Pale Ale 3. IPA

Question 38

Contributes to good head retention

Answer 38

1. isohumulones 2. high original gravity 3. moderate alcohol content 4. dextrins 5. levels of high- and medium- molecular weight proteins.

Question 39

Styles that should have good head retention (3)

Answer 39

1. German Pils 2. Witbier 3. Belgian Blond Ale.

Question 40

Styles which may have low or impaired head retention

Answer 40

1. Eisbock 2. Imperial Stout 3. English and American Barleywines.

Question 41

Lightstruck is skunk and ?

Answer 41

Coffee beans

Question 42

Metallic due to

Answer 42

oxidation of lipids in | - improperly stored malt

Question 43

Onion or catty

Answer 43

Mercaptans

Question 44

Paper or cardboard

Answer 44

(E)-2-nonenal

Question 45

Dark malty beers oxidization taste

Answer 45

More sherry like

Question 46

Clove and spicy

Answer 46

Phenol 4-vinyl guaiacol From ferulic acid

Question 47

Medicinal

Answer 47

Phenolic From wild yeasts - esp chlorophenols

Question 48

Sherry like

Answer 48

oxidation of melanoidins

Question 49

bitter almonds, marzipan, dried cherries and cherry stones

Answer 49

Benzaldehyde

Question 50

Solvent like

Answer 50

Usually from ethyl acetate (ester) and fuselage alcohols

Question 51

Sweet due to

Answer 51

1. Unfermented residual sugars - flocculent or low attenuating yeast - poor yeast health - low FAN - poor oxygenation 2. High gravity wort 3. High dextrin content 4. Lactose

Question 52

High residual sweetness ok in what styles (3)

Answer 52

Strong beers 1. Wee Heavy 2. English Barleywine 3. Eisbock

Question 53

High residual sweetness NOT ok in (4)

Answer 53

Dry styles 1. American lager 2. Berliner Weiss 3. Gueze 4. Saison

Question 54

Meaty brothy

Answer 54

Autolized yeast

Question 55

Yeasty flavor ok in (4)

Answer 55

1. Unfiltered German Lagers 2. Australian sparkling ale 3. Gose 4. Some Belgian ales