Chapter 7 - Common Elements in Winemaking and Maturation

Question 1

Name the constituent parts of grapes.

Answer 1

Seeds; Stems; Skins; Bloom; Pulp

Question 2

What is the Bloom of a grape?

Answer 2

The waxy surface that covers the skins of the grapes and contains yeasts that can be used to ferment the wine.

Question 3

What is Protective or Anaerobic winemaking?

Answer 3

Techniques in which all efforts are made to keep grapes and juice away from oxygen, including filling airtight winery equipment with either CO2 or nitrogen before they are used for grape processing. Vital to create a wine dominated by primary fruit characteristics.

Question 4

True or False? Wines that are matured aerobically are stored in wooden vessels that are normally made of oak

Answer 4

True

Question 5

What can oxygen do during a wine’s maturation?

Answer 5

Since it is not airtight, small amounts of oxygen can make it through and react with the wine. This can help to soften tannins in red wines. Primary fruit flavors will gradually fade and tertiary characters start develop. Color may also change due to the oxygen.

Question 6

Name two ways SO2 acts in wine making.

Answer 6

It acts as an antioxidant and an antiseptic.

Question 7

What are some of the aromas and flavors that can be passed on from oak?

Answer 7

Oak tannins give more structure to both red and white wines, increasing their textural complexity. Oak can also give aromas and flavors of toast, vanilla, smoke and cloves.

Question 8

What are two alternatives to using oak vessels?

Answer 8

Using small oak planks, called staves, or smaller oak chips.

Question 9

Why should the grape seeds never be crushed?

Answer 9

They can release bitter oils and tannin, and the wine may become unpleasantly astringent and bitter.

Question 10

When does pressing typically occur?

Answer 10

In the case of white wines, pressing occurs before the start of fermentation; for red wines this typically happens after fermentation.

Question 11

What is grape juice commonly referred to?

Answer 11

It is referred to as “must”.

Question 12

What is the must weight?

Answer 12

The level of sugar in the juice.

Question 13

What is RCGM?

Answer 13

Rectified Concentrated Grape Must - a colorless, odorless syrupy liquid used to increase sugar levels.

Question 14

What is Chaptalization?

Answer 14

Where sugar from sources other than grapes is added.

Question 15

How can acid levels be increased?

Answer 15

Acidification is normally carried out by the addition of tartaric acid in powder form.

Question 16

How can acid levels be decreased?

Answer 16

Excess acid may be neutralized by the addition of an alkali.

Question 17

What are the by-products of the fermentation of sugar?

Answer 17

Alcohol, CO2, Heat, Flavor compounds

Question 18

What is the yeast species responsible for the majority of wine fermentation?

Answer 18

Saccharomyces cerevisiae

Question 19

What is the temperature range where fermentation can happen?

Answer 19

Between 5 and 35 degrees celcius

Question 20

What are the two important ways in which a winemaker can control the fermentation process?

Answer 20

The choice of yeast and temperature management.

Question 21

What are two types of yeasts commonly used?

Answer 21

1) Naturally occurring yeasts

2) Commercially available cultured yeasts.

Question 22

What does fermenting at low temperatures do?

Answer 22

Avoids the loss of the most volatile aromas (often floral) and can encourage the development of fruity flavors in white wines.

Question 23

Why are higher temperatures needed during fermentation?

Answer 23

Necessary for the extraction of color and tannins from black grape skins.

Question 24

What is malolactic fermentation?

Answer 24

A secondary fermentation that occurs once the alcoholic fermentation is complete. Converts the tart malic grape acid into the softer lactic acids. It softens and reduces acidity, and can create buttery flavors.

Question 25

What is referred to as “gross lees”

Answer 25

Dead yeast cells and grape fragments that fall to the bottom of the fermentation or storage vessel.

Question 26

What are the three primary methods to clarify wine?

Answer 26

Sedimentation; Fining; Filtration

Question 27

How does Sedimentation work?

Answer 27

It relies on gravity to pull the suspended particles to the bottom of the liquid.

Question 28

What is Racking?

Answer 28

When wine is gently pumped into a new vessel, leaving the sediment behind. This is a process that is often repeated to continually clarify the wine.

Question 29

What is Fining?

Answer 29

Adding a fining agent to the wine, a substance that forms bonds with certain wine constituents and causes visible clumps to form. These clumps can then be removed by filtering.

Question 30

What is Filtration?

Answer 30

A process that physically removes particles from a wine as it is passed through a filter.

Question 31

What are the two methods of Filtration?

Answer 31

1) Depth Filtration - can also remove gross lees

2) Surface Filtration

Question 32

What are the three important areas that require stabilization?

Answer 32

1) Tartrate Stability (dealing with tartaric acid crystals)
2) Microbiological Stability (dealing with microorganisms that can spoil wine - yeasts and bacterium)
3) Oxygen Stability (dealing with excess levels of oxygen)

Question 33

What causes cork taint?

Answer 33

TCA - trichloroanisole

Question 34

What is an advantage of screw-caps?

Answer 34

By preventing oxygen to enter the bottle, they help preserve the primary aromas and fruit flavors.