Ch. 16: White Winemaking

Question 1

Skin contact

Aim, when maximized, when miminized, key factors

Answer 1

The process soaking the juice with the skins on crushed grapes.

For white wine, the aim is to extract flavor and aroma compounds and enhance texture.

It is effective for aromatic varieties such as Gewurz, Viognier, Riesling, Sauv Blanc, and Muscat that have lots of aroma compounds as it maximizes flavor extraction.

Skin contact is limited for wines with delicate fruity flavors, smooth texture, and light color are desired. It is also limited for wines to be drunk quickly, as the tannins would not have time to soften.

Time and temperature are the two key factors that influence extraction. For white wine, grapes typically are soaked anywhere from 1 to 24 or more hours below 59F and pressed to separate the skins from the juice before fermentation.

Question 2

Hyperoxidation

Answer 2

Exposing the must to large amounts of oxygen before fermentation to target the compounds that oxidize most quickly and remove them during fermentaion so that the wine is less likely to oxdize after fementation.

It can destroy volatile aroma compunds such as methoxypyrazines and thiols, so is better suited for non-aromatic grapes, such as Chardonnay. Higher-end chardonnay that you would age (solves the Burgundy pre-ox problem). Not expensive.

Question 3

Flotation

Answer 3

Bubbling up gas through the must so that solids float to the top and can be skimmed off.

Fining agents must be used in order for this to be effective (to help bind particles together)

It is effective and quick, and can be used as a continuious or batch process. The must does not need chilling. These save time and money.

The expenses comes from the equipment - gasses, fining agents, and equiment for bubbling the gas through the liquid. But they are not steep.

Typically, a neutral gas such as nitrogen is used, or oxygen can be used if hyperoxidation is desired.

Must only

Question 4

Pectolytic enzymes

Answer 4

Clarifying agent that breaks down pectins in the must, allowing quicker separation between the juice and solids.

The cost is justified by the time and energy saved compared to sedimentation.

Must only

Question 5

Pectins

Answer 5

A compund naturally found in plant cells. In winemaking, breaking them down aids clarification, making the juice easier to separated from the solids.

Question 6

Bâttonage

Answer 6

During aging, when lees are stirred to mix them into the wine. Increases yeast compounds. Decreases reductive sulfur compounds.

Traditionally done by hand, where bung has to be removed, increasing oxygen contact.

Labor intensive and can increase costs.