MTB 1: Post-Fermentation Operations Flashcards Preview

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Flashcards in MTB 1: Post-Fermentation Operations Deck (88)
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1

What causes the increase in VA?

The gradual oxidisation of aldehydes, producing acetic acid.

2

Ideal bulk storage temp. for red:

Between 10 and 20 degs, ideally 15.

3

Ideal bulk storage temp. for delicate whites and rosés:

Below 10 degs

4

Optimum humidity level:

75-85%

5

Free SO2 levels needed to stop oxidation:

At least 20 mg/L

6

Define 'ullage'

The amount by which a container falls short of being full.

7

Inert gases used for blanketing and prevention of spoilage yeast/bacteria:

Nitrogen (low solubility, used to sparge wine, removes dissolved oxygen, for reds), carbon dioxide (dense, dissolves well, whites) and argon (pricey).

8

Benefits of micro-oxygenation:

Reduction of herbaceous aromas, better structure, better oak integration, control of reduction.

9

Why do oxidatively aged wines become more concentrated?

Because of evaporation.

10

In biological ageing, ethanal degrades resulting in...

Diethyl acetyl

11

Lees encourage...

MLF - providing nutrients.

12

Too thick or unstirred lees can lead to...

Hydrogen sulphide or mercaptan odours.

13

Effects of small barrels (less than 500 litres):

Reduction of fresh aroma, early tannin polymerisation, stabilisation and clarification.

14

Two kinds of oak:

Red (not porous, no good for winemaking) and white (used for winemaking).

15

Quercus alba:

American, low phenols, high aromatics - oak lactone (coconut).

16

Quercus petraea (/sessiliflora):

European, tighter grained, less tannin, highly aromatic - eugenol (cloves), phenol aldehydes - vanillin (oak/vanilla).

17

Quercus robur:

Pendunculate (bearing a stalk with a flower/fruit), not particularly aromatic, but highly extractable polyphenols.

18

Typical barrel costs (225l barrique):

French: €600-€800, American €440.

19

Key oak origins (France):

Tronçais, Allier, Nièvre (central, v. tight grain), Vosges (NE) and Limousin (east of Cognac, tighter and tannic wood).

20

Oak origins (rest of Europe):

Russian, Hungarian, Slavonian (Italy) and Portuguese - cheaper.

21

Oak origins (USA):

Oregon, Minnesota and Wisconsin.

22

Cutting oak:

Sawing vs. splitting. European split along grain to avoid leakage. American can be sawn to maximise yield.

23

Drying oak:

Air vs. kiln. Air-drying leaves less tannic wine. French oak usually left in air for 18-36 months.

24

Toasting:

Degrades wood structure, leaves aromatic compounds. Less toast: tannins and wood notes. More toast: toasty and spicy. Lack of seasoning can make wine sappy/astringent.

25

Fuder size:

1000L

26

Hoghead size:

300L

27

Puncheon size:

500L

28

Shaving and re-charring:

Can add on 10 years more life, but leaves them more brittle and flavours rarely as subtle/well-integrated.

29

Adding oak chips:

Most effective when added during fermentation.

30

Adding oak staves:

During fermentation or maturation.