16. Specific options for white winemaking

Question 1

What is the purpose of skin contact in white wines?

Answer 1

-enhance extraction of aroma and flavor compounds, enhance texture with small amount of tannin

–Not common

Question 2

What are the two key factors that can influence extraction during skin contact?

Answer 2

Time and Temperature

• Greater time on skins leads to greater extraction of flavor and tannin
• Chilling juice during this reduces rate of extraction, permitting more control, reducing risk of spoilage and spontaneous fermentation

Question 3

What’s the difference between skin contact white wines and orange wines?

Answer 3

Orange wines are FERMENTED on their skins. Skin contact whites are not.

Question 4

How are skins of white wines handled at pressing?

Answer 4

Very gently to avoid extraction of unwanted compounds.

Question 5

How are the majority of white wines made?

Answer 5

Zero or minimal skin contact. generally crushed and pressed immediately because the principle aroma and flavor compounds desirable in white grapes are in the pulp

Question 6

Why would a winemaker choose to have skin contact with white grapes?

Answer 6

• Skin contact maximizes flavor extraction

- It is a way of enhancing texture without the use of oak

Question 7

Why would a winemaker choose NOT to have skin contact with white grapes?

Answer 7

• Minimal skin contact is typical for wines where delicate fruity flavors, minimal color, and a smooth mouthfeel are desired.
• typically a choice for wines meant to be drunk early
• If fruit is under-ripe, skin contact would extract bitter flavors and astringent tannins.
• skin contact is a slow process, uses equipments and labor, therefore expensive. time = money

Question 8

Why would the choice be to press whole bunches of white grapes?

Answer 8

• Reduces chance of oxidation before and during pressing, especially if inert gasses are used within the press.
• One of the most gentle forms of pressing because it provides juice that is low in solids (skins, stems, seeds), tannin, and color.
• Stems help break up mass of grape skins providing channels for the juice to drain.
• ONLY AN OPTION IF GRAPES HAVE BEEN HAND HARVESTED.

Question 9

When is whole bunch pressing white grapes suitable?

Answer 9

• If grapes have been hand harvested.
• For smaller batches of premium wines. Whole bunches mean fewer grapes can be loaded into the press as they take up a lot of room in the press.

Question 10

Why would a winemaker choose to make wine entirely from free run juice?

Answer 10

• if they want to make a lighter bodied style of wine and minimize any color or tannin.
• However, this reduces the final volume of wine that can be produced and therefore has a cost implication.

Question 11

What are press fractions?

Answer 11

Stages of wine during pressing. At the beginning, juice will be similar to free run, but as pressing continues, more solids, tannin, and color are extracted. Winemaker may decided to separate different stages into “fractions”

Question 12

How may press fractions be used in white winemaking?

Answer 12

Different press fractions may be blended with free run juice in winemaking and/or maturation to increase body and texture.
-Final press fractions are likely to be discarded as are likely to be astringent and bitter.

Question 13

What is hyper oxidation?

Answer 13

• technique of deliberately exposing the must to large quantities of oxygen before fermentation.
• equipment is not expensive, but it is an extra step in the winemaking process the requires labor and time, which cost money.

Question 14

What is the main aim of hyper oxidation?

Answer 14

-To produce wines that are more stable against oxidation after fermentation

Question 15

How does hyperoxidation work?

Answer 15

• Targets compounds that oxidize most readily
• destroys some of the most volatile aroma compounds found in the must and therefore typically suited to non-aromatic grape varieties, like Chardonnay

Question 16

What are the 4 options for clarifying the must?

Answer 16

• Sedimentation
• Flotation
• Centrifugation
• Clarifying agents

Question 17

During the winemaking process, at what point would clarification be carried out?

Answer 17

Between pressing and fermentation, the juice of white grapes may be clarified.

Question 18

What is the aim of clarification?

Answer 18

-to reduce the amount of suspended solids

Question 19

What do higher levels of solids give to a wine?

Answer 19

• a greater range of aromas from fermentation, added texture, subtle astringency
• ex: premium-priced Chardonnay

Question 20

What do lower levels of solids give to a wine?

Answer 20

• better for fruity aromas

- ex: inexpensive pinot grigio

Question 21

Fermentations with high levels of solids need careful monitoring because of..?

Answer 21

-various compounds within solids and their reaction can lead to off-flavors. Example: reductive sulfur compounds at high levels smells like rotten eggs

Question 22

What can over-clarifying the must lead to?

Answer 22

-Stuck fermentations

Question 23

What is sedimentation?

Answer 23

• Simplest form of clarification. Suspended solids in the must are left to fall over time with gravity.
• Also used to clarify wines
• Simplest, but takes the longest, therefore costly in terms of labor, time, and energy to chill the must.

Question 24

The rate of sedimentation is determined by what?

Answer 24

• size and shape of vessel - takes longer in large, tall vessels due to the depth needed to fall.
• temperature of the must. Low temps take longer. 12-24 hours for sedimentation is not uncommon.

Question 25

Why are musts chilled during sedimentation?

Answer 25

-to reduce the rate of oxidation and threat from spoilage organisms, avoiding spontaneous fermentation.

Question 26

What is the process of flotation?

Answer 26

• Involves bubbling gas up through the must. As bubbles rise, they bring solid particles. Solid particles are then skimmed off the top.
• If oxygen is the gas used, this is also a process of hyper oxidation.
• Fining agents must be used in order for this to be successful
• Effective and quick, but a little more expensive than sedimentation due to equipment.
• can be either continuous or batch process
• Can only be used on must, not on wine.

Question 27

What is centrifugation?

Answer 27

• use of a centrifuge to rapidly clarify the must
• used continuously
• expensive to buy therefore generally used in large-volume production
• can be used on wine and must

Question 28

What are Pectolytic enzymes and what role do they play in clarification?

Answer 28

A clarifying agent used to break down pectins in the must.

They only aid in clarification of the must, not the wine.

Question 29

What’s the difference between temperatures used for fermenting white wine vs red wine?

Answer 29

-cooler temps for white wine.

Question 30

Why would stainless steel be used in white winemaking?

Answer 30

• -Most popular choice for fruity, floral white wines.

- Can be temperature controlled in order to enhance fruity, floral aromas

Question 31

Why would concrete and oak be used in white winemaking?

Answer 31

-May be used to ferment at slightly warmer temps where maximizing fruity and floral aromas is not the aim.

Question 32

What effect does fermenting in oak have on white wines?

Answer 32

• popular choice for some styles of white, particularly premium chardonnay.
• oxidative environment, thought to give deeper color and fuller body.
• gives blending options as each barrel may be slightly different after fermentation
• generally not used for aromatic grapes.

Question 33

What are the effects of MLC for white wines?

Answer 33

• Reduction in acidity, increase in microbiological stability, modification of flavors.
• In white wine, the winemaker typically makes a choice whether or not to put wine through MLC because it makes a significant difference to the style.
• MLC decreases acidity and increases pH

Question 34

What are the aims of lees aging for white wines?

Answer 34

-to give more body, soften the mouthfeel, help stabilize the wine. They also protect the wine from oxygen and may introduce some reductive compounds.

Question 35

Why is lees stirring considered an oxidative process?

Answer 35

-Because of the need to remove the bung to stir the lees, which introduces oxygen into the environment

Question 36

What are the effects of lees stirring?

Answer 36

• increases oxygen exposure
• increased effects from dead yeast
• decrease in fruity flavors
• reduces development of reductive sulfur compounds
• labor intensive, therefore can add to the cost of production.

Question 37

Skin contact for white wines is most effective on what type of grapes?

Answer 37

most effective on aromatic grape varieties that have lots of aroma compounds that can be extracted - Riesling, Gewurtz, Viognier, etc

Question 38

If a winemaker is making a premium priced chardonnay, what is the typical choice regarding solids and why?

Answer 38

The winemaker would leave a higher amount of solids in the wine to give better aromatics from fermentation, subtle astringency, added texture

Question 39

If a winemaker is producing an inexpensive Pinot Grigio, what is the typical choice regarding solids and why?

Answer 39

The choice would be to remove most solids to retain fresh, fruity characteristics of the wine.

Question 40

Regarding acidity and sugar, how does free run juice compare to press juice and how does it affect the final wine?

Answer 40

• free run juice has more acidity, more sugar, makes fresh and fruity wines
• press juice has lower acidity and less sugar, makes wines that are fuller bodied.