Winemaking

Question 1

What are the constituent parts of the grape?

Answer 1

Seeds, stems and skins which contain tannins, the pulp which contains sugar, water and acids, and the bloom, which contains yeasts which can be used for fermentation.

Question 2

How is exposure to oxygen reduced during winemaking?

Answer 2

Grapes may be picked at night and kept chilled; antioxidants such as sulfur dioxide maybe used, and wine may be matured in an airtight container such as stainless steel.

Wine made oxidatively may be matured in oak vessels; 225 barriques allow more oxygen exposure than larger barrels.

Question 3

What does sulfur dioxide do in winemaking?

Answer 3

Protects the grape juice against the effects of oxygen and acts as an antiseptic, limiting unwanted bacterial activity.

Question 4

What are the most important considerations when using oak for maturation?

Answer 4

Types of oak (French, American, Hungarian) have different characteristics.

Size - smaller barrels impart more oak than larger barrels.

Age - new barrels impart flavor whereas older barrels eventually impart only oxygen.

Question 5

What are alternatives to oak aging?

Answer 5

Inert vessels such as concrete and stainless steel (easy to clean, better temperature control)

Oak chips or staves (less expensive)

Question 6

What happens when grapes arrive at the winery?

Answer 6

They receive their first dose of SO2 and are sorted on a sorting table.

Question 7

What two winemaking steps are optional before pressing?

Answer 7

Destemming (unnecessary if grapes are machine harvested) and Crushing (liberates free-run juice)

Question 8

What are two types of presses and when does pressing occur?

Answer 8

Basket and bladder (pneumonic) press.

White wine is pressed prior to fermentation; red wine is pressed after.

Question 9

What are the most common adjustments in winemaking?

Answer 9

The addition of RCGM or chaptalization to adjust sugar; acidification or deacidification; these methods are not allowed in some regions.

Question 10

What is the name of the yeast used in fermentation?

Answer 10

Saccharomyces Cerevisiae

Question 11

How can a winemaker halt fermentation?

Answer 11

By sterile filtering, temporary halting by chilling wine to 5 degree or lower, or killing them with SO2 or neutral grape spirit.

Question 12

What two types of yeast must a winemaker choose between?

Answer 12

Ambient and cultured.

Question 13

In general, what effect does fermentation at high verses low temperatures have?

Answer 13

Lower temperature preserve floral aromas and bring out the fruitiness of the wine; high temperatures are required for color and tannin extraction.

Question 14

What are the constituents of wine?

Answer 14

Water 70-90%
Ethanol 8-22%
Sugars .1-20%
Tannins up to .4%
Acids .3-1%
Compounds .2%

Question 15

What is Malolactic Fermentation?

Answer 15

Not a fermentation, but a bacteria that converts tart malic acid to softer lactic acid, typically after fermentation. It can be encouraged or prevented by raising or lowering the temperature, and through the absence or use of SO2.

Question 16

What are lees?

Answer 16

Dead yeast cells and other particles that fall to the bottom of the vessel. Gross lees are generally removed right away, but a winemaker may choose to age a white sur lies to impart a biscuity, brioche quality to the wine.

Question 17

What are three reasons a winemaker might blend her wine?

Answer 17

Balance, consistency and style.

Question 18

How might a wine be clarified?

Answer 18

Sedimentation - allowing the large particles to fall to the bottom of a vessel by gravity.

Racking - pumping the wine from one container to another, leaving the sediment behind.

Fining - optional, adding a fining agent to which particles in the wine will bind, in order to be removed by filtration.

Filtration - depth filtration for larger particles and surface filtration for smaller ones. Also optional.

Question 19

Why might a wine undergo stabilization?

Answer 19

To prevent the later development of tartrate crystals (wine diamonds) by chilling the wine (cold stabilization).
To prevent microbiological activity (sterile filtration)
To prevent oxidation (topping up with SO2)

Question 20

What are three types of wine closures?

Answer 20

Cork, synthetic cork, stelvin or screw caps

Question 21

What qualities allow a wine to mature and improve in bottle?

Answer 21

Acid, tannin or sugar and concentration of flavor.

Question 22

At what temperature does white wine fermentation take place?

Answer 22

12-22 degrees C

Question 23

What choices must be make in white winemaking?

Answer 23

skin contract, clarity, fermentation temperature and vessel, MLF, lees, blending, clarification and stabilization

Question 24

Compare the production of an inexpensive white wine, an aromatic wine and a premium wine.

Answer 24

An inexpensive white wine will be made from a neutral wine such as pinot grigio or chardonnay, protected from oxygen, destemmed and crushed, acidified, highly clarified, fermented in stainless steel, possibly flavored with oak staves/chips, often fermented to dryness, then sweetened with unfermented grape juice, stabilized, clarified, and topped up with SO2.

Aromatic grapes will be handled carefully with SO2 levels monitored; gentle clarification; cold fermentation in inert vessels to preserve fruit and floral aromas; little post-fermentation treatment.

Premium Chardonnay or Pinot Gris will also be handled carefully with SO2 levels monitored, gentle clarification; stainless steel, old oak or new oak may all be used for fermentation or maturation; for Chardonnay, MLF may be encouraged as well as lees aging.

Question 25

What are three methods of making sweet wine?

Answer 25

Stopping fermentation, adding a sweetening component, and concentrating the sugars in the grape.

Question 26

What are four ways to concentrate sugar in the grape?

Answer 26

noble rot
drying grapes on the vine (passerillage)
drying grapes after harvest
freezing grapes on the vine

Question 27

What is the point of pre-fermentation extraction in red wine making?

Answer 27

also known as cold maceration or cold soak, this process is designed to extract color and flavor, not tannin.

Question 28

At what temperature does red wine fermentation take place?

Answer 28

20-32 degrees C

Question 29

What are common cap management techniques?

Answer 29

punching down - by hand or mechanical paddles
pumping over - pumping bottom juice over the top
rack and return - draining juice into different container and returning
rotary fermenters - rotating horizontal tanks

Question 30

What vessels are best for red wine fermentation?

Answer 30

open topped steel or concrete; oak is impractical because it does not provide enough contact between wine and skins.

Question 31

What is press wine?

Answer 31

Once the free run juice is drawn off the skins, the remaining juice is pressed. Different presses have different qualities and may be kept separate for blending.

Question 32

What is intracellular fermentation?

Answer 32

When whole bunches are protected from oxygen, they produce a little alcohol in their cells, without the involvement of yeast?

Question 33

What are three forms of whole bunch fermentation?

Answer 33

Carbonic maceration - vats are filled with whole cluster grapes and CO2, starting intracellular fermentation, when grape skins split and release their juice, pressing begins and traditional fermentation occurs.
Semi-carbonic maceration - whole clusters are placed in vats, crushing some of the bottom grapes. Fermentation begins, releasing CO2, which initiates carbonic maceration for the clusters above.
Whole bunch with crushed fruit - crushed fruit is mixed with wholes clusters, keeping them submerged and away from oxygen, initiating intracellular fermentation.

Question 34

What is the most important decision with respect to maturation in red wine.

Answer 34

Whether to use oak, and what type, size and age.

Question 35

What are three methods of rose production?

Answer 35

Direct press - red grapes are produced in the same method as white wine, crushed and pressed, then drained off the skins, extracting some color and flavor but little tannin.
Short maceration - grapes remain in contact with skins for a few hours as opposed to a few days, at which point the juice is drained off the skins and wine is produced much like a white wine
Blending - a small portion of red wine is added to white; not permitted in EU with the perception of Champagne.

Question 36

How is inexpensive red wine made?

Answer 36

Heavy use of SO2 to protect from oxidation, crushing destemming, acidification, high temp fermentation to maximize fruit flavors, sometimes carbonic or semi-carbonic maceration is used; stainless steel, older barrel, or oak chips are used; stabilized, fined, filtered and topped up with SO2