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

Vinification Flashcards by Suzanne DeStio

Define vinification

transformation of grape juice into wine

How well did you know this?

Not at all

Perfectly

Why is SO2 added to fermenting must or juice beforhand

prevents oxidation and bacterial contamination

- ensures rapid fermentation

How well did you know this?

Not at all

Perfectly

What chemical is a sign of oxidation in finished wines?

Acetaldehyde

How well did you know this?

Not at all

Perfectly

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

Acetaldehyde is converted to acetic acid
acetic acid reacts with alcohol = ethyl alcohol
ethyl alcohol is volatile acidity

How well did you know this?

Not at all

Perfectly

When VA is present as a fault, what happened?

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

How well did you know this?

Not at all

Perfectly

What does low Nitrogen levels in must lead to?

-formation of Hydrogen Sulfide H2S (rotten egg smell)

bc yeast needs N to work

How well did you know this?

Not at all

Perfectly

What are sulfites vs sulfides in winemaking terms?

sulfites - SO2

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

How well did you know this?

Not at all

Perfectly

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

large

How well did you know this?

Not at all

Perfectly

What temp range is yeast active?

50-113*F

How well did you know this?

Not at all

Perfectly

What temp can red wine fermentation reach

90s

-about 95 can risk volatized flavor compounds and stuck fermentations

How well did you know this?

Not at all

Perfectly

What is benefit of hot fermentation for red wine?

increased extraction of color, tannin, and flavor compounds

How well did you know this?

Not at all

Perfectly

How long is range for fermentation depending on yeast used?

a week to a month to ferment dry

How well did you know this?

Not at all

Perfectly

Ways to remove alcohol from wine?

spinning cone - modern (centrifuge)

- reverse osmosis

How well did you know this?

Not at all

Perfectly

Two constituents of reverse osmosis?

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

How well did you know this?

Not at all

Perfectly

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

Yes, as of 2009

-cant be adjusted by more than 2%

How well did you know this?

Not at all

Perfectly

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

Tartaric and malic acid

Tartaric acid added prior to fermentation is preferred

How well did you know this?

Not at all

Perfectly

Compound responsible for butter aromas in wine? Result of?

Diacetyl

-results of Malo

How well did you know this?

Not at all

Perfectly

What environment required for Carbonic Maceration?

Anaerobic - No oxygen!

-happens under blanket of CO2 in tank

How well did you know this?

Not at all

Perfectly

What is MOG

Materials Other than Grapes

-removed during sorting

How well did you know this?

Not at all

Perfectly

Name of machine used to crush grapes?

Crusher-destemmer

How well did you know this?

Not at all

Perfectly

What is cold soak?

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

Are grape skins included in fermentation for red wines?

Yes

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

What is the chapeau?

Cap

Cap management techniques

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

What is vin de goutte

high quality free run wine drained first from tank

What is result of pressing pomace

vin de presse - coarser, more tannic

basket press vs pneumatic bladder?

basket press - vertical pressure | pneumatic bladder - gentle pressure via inflation with air

what is élevage?

maturation period

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

- soutirage - movement of wine from one vessel to another - provides aeration and clarification, removes wine from lees/sediment

When does ML fermentation occur in red wine?

quickly at end of fermentation or slowly during maturation

When is SO2 often added for red wine?

during maturation or just before bottling

When is wine fined/filtered?

prior to bottling, after being racked a final time

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

- collage (fining) - filtration promotes stability - fining and filtering promote clarity

Common fininf agents

- bentonite (clay from volcanic ash) - casein (milk protein) - egg white - isinglass (sturgeon bladder) - gelatin - egg whites

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

Débourbage | -juice can be racked off solids and clarified before fermentation

What is cold filtration for in white wine production?

-causes tartrate crystals to precipitate out at 25*F

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

-sugar content can lead to unexpected refermentation in bottle!

4 methods of rose winemaking

- blending - limited skin maceration - direct press - saignée

Is blending allowed in EU for rose?

- PROHIBITED but only below PGI! | - Most appellations preclude it, but Champagne obv allows it

Describe limited skin maceration for rose?

- red grapes subjected to short period of skin contact BEFORE fermentation - can be several hours to several days

Describe Saignée

- bleed juice from maceration - create rose as byproduct of red wine fermentation - concentrates must for red wine

Describe direct press

- don't crush grapes at all - super pale hue - direct pressing of whole red grapes or clusters

What does New oak contribute to wine?

- flavor - lactones, phenolic aldehydes like vanillin | - wood tannin

When does oak barrel become neutral?

4th-6th year of use | -most of flavor transmitted during 1st year

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

-micro-oxygenation (micobullage) + -oak chips

Species for French and American oak? Difference in grain?

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

Why is French oak split and American sawn?

- 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)

Difference in drying btwn French/American oak?

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

3 stages of making barrel?

- warming (chauffage) - shaping (cintrage) - toasting (bousinage)

What is bousinage

toasting inside of barrel

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

light

What is Foulage

old act of stomping grapes with feet