Unit 2 - Week 6

Question 1

Ascorbic acid

Answer 1

vitamin C. antioxidant used to supplement antioxidant role of SO2. can not replace SO2 as it has no antiseptic effect.

Question 2

What is result of using ascorbic acid without presence of SO2

Answer 2

ascorbic acid will form hydrogen peroxide - a bleaching agent.

Question 3

What is fermentation

Answer 3

fermentation is breakdown of sugars to release carbon dioxide, ethanol (or ethyl alcohol) and energy by the anaerobic (oxygen-free) metabolism of yeast.

Question 4

yeast genus responsible for alcohol fermentation

Answer 4

saccharomyces. 16-18 g/l of sugar needed to create each 1%ABV.

Question 5

What is dominant sugar at begining of ripening process

Answer 5

Glucose

Question 6

Which sugar is accumulated more rapidly in berries

Answer 6

Fructose (taste sweeter). can become dominant sugar in very ripe grapes.

Question 7

What kind of sugar yeasts prefer

Answer 7

glucose. fermenting fructose rich grape must to total dryness can be difficult.

Question 8

What happen when sucrose is added to must

Answer 8

sucrose molecules are broken down into glucose and fructose molecules

Question 9

What is glycerol (or glycerine)

Answer 9

main by-product of fermentation. colorless, viscous liquid, slighty sweet taste, contribute to smoothness and weight of wine

Question 10

Other by-products of fermentation

Answer 10

acetaldehyde, ethyl acetate, aroma esters, fusel oils.

Question 11

This fermentation vessel is easy to clean and maintain. Temperature control is simple, automation

Answer 11

stainless steel tanks

Question 12

Wooden fermentation vessels

Answer 12

temperature control is important, hygiena. popular choice esp. for red wine maceration after fermentation. retention of heat and high solids to liquid contact due to the shape of the vessel aids extraction

Question 13

This fermentation vessels are lined either by epoxy or glass, they are cheap to install, easy to clean and maintaine. Temperature control is simple

Answer 13

Cement tanks. oxygen exchange does not occur as it does with wooden fermentation vessels.

Question 14

Name some of the indigenous yeasts found in the bloom on the grape skins

Answer 14

kloeckera/hanseniaspora; candida; metschnikowia

Question 15

What wine uninoculated fermentation produce

Answer 15

more complex wines because more yeast specieas are involved, hence more chemical reactions have occured, thus more products and by-products produced

Question 16

What is pied de cuve

Answer 16

starter culture

Question 17

What is inoculated fermentation

Answer 17

active dry yeast preparations made from pure cultures of different strains of saccharomyces cerevisiae

Question 18

Lalvin Rhone 2226 (saccharomyces cerevisiae)

Answer 18

tolerance to high sugar levels

Question 19

Lalvin Rhone 2323 (saccharomyces cerevisiae)

Answer 19

efficient extraction of phenolics, enhacment of tannin structure for high quality reds

Question 20

Maurivin Cru-Blanc (saccharomyces cerevisiae)

Answer 20

higher glycerol production levels

Question 21

R2 (saccharomyces cerevisiae)

Answer 21

low temperature tolerant yeast for very fruity white styles

Question 22

Lalvin K1V-1116 (saccharomyces cerevisiae)

Answer 22

sauvignon blanc yeast for aroma/thiol fixing

Question 23

what kind of yeast used for secondary fermentation in bottle

Answer 23

low foaming (champagne yeast e.g. Premier Cuvee)

Question 24

At what temperature are red wines fermented

Answer 24

20-32 C if temperature goes above 35-38 fermentation may stop

Question 25

At what temperature are white wines fermented

Answer 25

10-18

Question 26

What flavors gives isoamyl acetate

Answer 26

banana/pear drop aromas

Question 27

What can be done when fermentation stuck

Answer 27

increase nutrient levels by adding nitrogen-rich products such as di-ammonium phosphate (DAP) or thiamine (vitamin B)

Question 28

What kind of must is low in nutrients

Answer 28

high clarified must and must from rotten fruit. addition of DAP (usually 200 mg/l) and thiamine (1 mg/l) addition of ammonium sulfate liberates both ammonium (source of nitrogen) and sulfur dioxide

Question 29

What happened when yeasts are deprived of nitrogen (as ammonium)

Answer 29

yeast will break down amino acids present in fermenting must releasing hydrogen sulfide (H2S) which smells like rotten eggs.

Question 30

Carbon dioxide (CO2)

Answer 30

colorless, odorless, lethal gas, heavier than oxygen.

Question 31

At what temperatures are aromatic wines fermented

Answer 31

11-15 C to retain fruit esters, even 10-13 C to retain maximum volatile esters. drawback is intense smelling esters are sometimes formed such as isoamyl acetate

Question 32

Battonage is

Answer 32

lees stirring

Question 33

Name three ways of making rose

Answer 33

drawing-off (saignee or bleeding) direct pressing blending

Question 34

Drawing-off (saignee or bleeding)

Answer 34

most widely used. destemmed, crushed and sulphited grapes. skin contact 6-48 hours. fermentation in anaerobic conditions. MLF is blocked. cooler temp. - retain aromatics and preserve freshness higher temp. - more coloring compounds

Question 35

Direct pressing

Answer 35

resulting must is pale pink in color and treated as white must.

Question 36

What are phenolic compounds (polyphenols)

Answer 36

large group of compounds based on the phenol molecule.

Question 37

Name two main types of phenolic compounds (polyphenols)

Answer 37

Non-flavonoids Flavonoids

Question 38

Non-flavonoids

Answer 38

simpler phenolics such as resveratrol, benzoic and cinnamic acids

Question 39

Flavonoids

Answer 39

substances such as anthocyanins, catechins

Question 40

Anthocyanins

Answer 40

red pigments found in skin cell that produce red color in red wines

Question 41

Tannins

Answer 41

polymerised catechin molecules that produce astrigency. smaller the tannin more bitter it is.

Question 42

Name three factors on which depends phenolic extraction

Answer 42

phenolic extraction occurs during alcoholic fermentation, depends on: temperature of fermentation cap management duration of skin contact

Question 43

What is a purpose of cold soaking in red wine production

Answer 43

to aid color extraction. destemed, crushed grape must is cooled to below 15 C for 3-7 days higher amount of SO2 is added, 80-100 mg/l

Question 44

What is thermovinification

Answer 44

heating grape crop 60-80 C for 20-30 minutes to extract phenolic compounds but can produce coarse wines with burnt aromas.

Question 45

What are benefits of fermenting red wine at moderate temperature (25 C)

Answer 45

this temperature favor good color extraction, preservation of primary fruit aromas, minimal to moderate tannin extraction. higher temperature - more tannin extracted

Question 46

Remontage (cap management)

Answer 46

pumping-over, merlot, cabernet sauvignon

Question 47

Pigeage (cap management)

Answer 47

punching down, pinot noir, syrah

Question 48

delestage (cap management)

Answer 48

rack and return

Question 49

rotovinification (cap management)

Answer 49

nebbiolo

Question 50

autovinification (cap management)

Answer 50

port

Question 51

Duration of skin contact for light, easy drinking reds

Answer 51

8 days

Question 52

Duration of skin contact for full body, intended for ageing

Answer 52

3 weeks

Question 53

Duration of skin contact for high quality vintages

Answer 53

1 month, can lead to softening of tannins due to polymerisation.

Question 54

What can be used to increase extraction of color and tannins during skin contact process

Answer 54

comercially available pectolytic enzymes

Question 55

What phenolic compounds are extracted first

Answer 55

anthocyanins extracted first then tannins

Question 56

What is carbonic maceration

Answer 56

fermentation within the berry itself. no yeast required. grapes own respiration, under anaerobic conditions converts sugar to ethanol.

Question 57

What are particular aromas produced during carbonic maceration

Answer 57

bananas, kirsch, cherry, plum.

Question 58

Semi-carbonic maceration

Answer 58

Beaujolais, deeply colored, fruity soft tannins

Question 59

Flash expansion

Answer 59

placing pre-heated grapes (65-90 C) in intense vacuum