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Viticulture/Vinification - SD > Vinification > Flashcards

Vinification Flashcards

1
Q

Define vinification

A

transformation of grape juice into wine

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2
Q

Why is SO2 added to fermenting must or juice beforhand

A
  • prevents oxidation and bacterial contamination

- ensures rapid fermentation

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3
Q

What chemical is a sign of oxidation in finished wines?

A

Acetaldehyde

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4
Q

What is acetaldehyde converted to in new wine and what happens when that compound reacts with alcohol?

A
  • Acetaldehyde is converted to acetic acid
  • acetic acid reacts with alcohol = ethyl alcohol
  • ethyl alcohol is volatile acidity
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5
Q

When VA is present as a fault, what happened?

A

Excess of acetic acid produced by activity of acetobacter (same bacteria that makes wine into vinegar in presence of oxygen)

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6
Q

What does low Nitrogen levels in must lead to?

A

-formation of Hydrogen Sulfide H2S (rotten egg smell)

bc yeast needs N to work

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7
Q

What are sulfites vs sulfides in winemaking terms?

A
  • sulfites - SO2

- sulfides - H2S, mercaptans(thiols), and other foul smelling compounds produced under reductive conditions

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8
Q

Would you use small or large vessel if you want a short, hot fermentation?

A

large

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9
Q

What temp range is yeast active?

A

50-113*F

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10
Q

What temp can red wine fermentation reach

A

90s

-about 95 can risk volatized flavor compounds and stuck fermentations

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11
Q

What is benefit of hot fermentation for red wine?

A

increased extraction of color, tannin, and flavor compounds

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12
Q

How long is range for fermentation depending on yeast used?

A

a week to a month to ferment dry

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13
Q

Ways to remove alcohol from wine?

A
  • spinning cone - modern (centrifuge)

- reverse osmosis

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14
Q

Two constituents of reverse osmosis?

A 
permeate 
--- contains water and ethanol
--- distilled to proper level before recombined
retentrate
--- wines aromatic compounds
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15
Q

Is de-alcoholization by physical separation legal in EU? How much can it be adjusted

A

Yes, as of 2009

-cant be adjusted by more than 2%

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16
Q

Two main acids used for acidification? Which is preferred, when?

A

Tartaric and malic acid

Tartaric acid added prior to fermentation is preferred

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17
Q

Compound responsible for butter aromas in wine? Result of?

A

Diacetyl

-results of Malo

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18
Q

What environment required for Carbonic Maceration?

A

Anaerobic - No oxygen!

-happens under blanket of CO2 in tank

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19
Q

What is MOG

A

Materials Other than Grapes

-removed during sorting

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20
Q

Name of machine used to crush grapes?

A

Crusher-destemmer

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21
Q

What is cold soak?

A
  • pre-fermentation maceration technique
  • relies on substantial SO2 additions and cold temp
  • maybe up to a week
22
Q

Are grape skins included in fermentation for red wines?

A

Yes

  • fermentation and maceration occur in tandem
  • want to extract phenols like tannin, color, anthocyanin, flavor with help of heat and alcohol
23
Q

What is the chapeau?

A

Cap

24
Q

Cap management techniques

A

Pigeage - punch down
Remontage - pump over
Délestage - fully drain off into separate vessel, then pour over

25
Q

What is vin de goutte

A

high quality free run wine drained first from tank

26
Q

What is result of pressing pomace

A

vin de presse - coarser, more tannic

27
Q

basket press vs pneumatic bladder?

A

basket press - vertical pressure

pneumatic bladder - gentle pressure via inflation with air

28
Q

what is élevage?

A

maturation period

29
Q

what is racking? what is french word? what is point?

A
  • soutirage
  • movement of wine from one vessel to another
  • provides aeration and clarification, removes wine from lees/sediment
30
Q

When does ML fermentation occur in red wine?

A

quickly at end of fermentation or slowly during maturation

31
Q

When is SO2 often added for red wine?

A

during maturation or just before bottling

32
Q

When is wine fined/filtered?

A

prior to bottling, after being racked a final time

33
Q

What is french word for fining? Benefits of fining and filtering?

A
  • collage (fining)
  • filtration promotes stability
  • fining and filtering promote clarity
34
Q

Common fininf agents

A
  • bentonite (clay from volcanic ash)
  • casein (milk protein)
  • egg white
  • isinglass (sturgeon bladder)
  • gelatin
  • egg whites
35
Q

What is french word for letting juice settle? What is purpose?

A

Débourbage

-juice can be racked off solids and clarified before fermentation

36
Q

What is cold filtration for in white wine production?

A

-causes tartrate crystals to precipitate out at 25*F

37
Q

Why are off-dry and sweet white wines often filtered?

A

-sugar content can lead to unexpected refermentation in bottle!

38
Q

4 methods of rose winemaking

A
  • blending
  • limited skin maceration
  • direct press
  • saignée
39
Q

Is blending allowed in EU for rose?

A
  • PROHIBITED but only below PGI!

- Most appellations preclude it, but Champagne obv allows it

40
Q

Describe limited skin maceration for rose?

A
  • red grapes subjected to short period of skin contact BEFORE fermentation
  • can be several hours to several days
41
Q

Describe Saignée

A
  • bleed juice from maceration
  • create rose as byproduct of red wine fermentation
  • concentrates must for red wine
42
Q

Describe direct press

A
  • don’t crush grapes at all
  • super pale hue
  • direct pressing of whole red grapes or clusters
43
Q

What does New oak contribute to wine?

A
  • flavor - lactones, phenolic aldehydes like vanillin

- wood tannin

44
Q

When does oak barrel become neutral?

A

4th-6th year of use

-most of flavor transmitted during 1st year

45
Q

Two techniques that can be implemented to approximate effects of new barrel at fraction of cost

A

-micro-oxygenation (micobullage)
+
-oak chips

46
Q

Species for French and American oak? Difference in grain?

A

French - Quercus robur, Quercus petraea
—tight wood grain, bc of slow growth
American - Quercus alba
—wider grain, bc grow faster

47
Q

Why is French oak split and American sawn?

A
  • French is split (provides fewer staves) bc it prevents leakage
  • American is sawn bc it is less porous (has more Tylose) so no fear of leakage - releases more vanillin and lactones (coconut)
48
Q

Difference in drying btwn French/American oak?

A

French oak is air dried - gentle process, leaches out som aggressive tannin and flavor
American oak - kiln dried - fast, concentrates lactones

49
Q

3 stages of making barrel?

A
  • warming (chauffage)
  • shaping (cintrage)
  • toasting (bousinage)
50
Q

What is bousinage

A

toasting inside of barrel

51
Q

What level of toasting leads to most extraction of wood tannin?

A

light

52
Q

What is Foulage

A

old act of stomping grapes with feet

Viticulture/Vinification - SD (2 decks)

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