White and Sweet Winemaking

Question 1

Where would it be common to blend different vintages to achieve a house style?

Answer 1

Champagne

Question 2

What size barrel is best for oxidation? Why?

Answer 2

• 225 liter barriques because there is more contact between the wine and the surface area of the barrel.
• Wines are rarely kept in barrique for more than 2 years
• wines matured in larger vessels can mature longer

Question 3

What is acidification and where does it happen most often?

Answer 3

The addition of tartaric acid in powder form. Occurs mostly in warm and hot regions.

Question 4

What is must weight?

Answer 4

The level of sugar in the un-fermented grape juice

Question 5

What is RCGM

Answer 5

Rectified Concentrated Grape Must - colorless, odorless syrupy liquid

Question 6

Name 3 wines that are deliberately made in an oxidative style.

Answer 6

• oloroso sherry/PX
• Tawny Port
• Rutherglen Muscat

-tertiary characters of carmel, toffee and nut

Question 7

What are natural wines?

Answer 7

wines made with minimal human intervention

Question 8

What is passerillage?

Answer 8

Drying grapes on the vine. Sometimes referred to as late harvest. A great alternative to Noble Rot.

Question 9

How can a winemaker can stop fermentation? Describe.

Answer 9

By killing or removing the yeast.

2 ways to kill yeast:

1) adding SO2
2) adding grape spirit

Removing yeast by filtration typically after fermentation has been temporarily halted by chilling the wine to below 5 degrees C

Question 10

What is enrichment?

Answer 10

increasing sugar levels by adding RCGM in order to produce a higher level of alcohol.

Question 11

What is chaptalisation?

Answer 11

using sugars from sources other than grapes, such as sugar beets to elevate alcohol during fermentation.

Question 12

What can happen to the wine if enrichment is not carried out with care?

Answer 12

It can produce a wine that is hard and thin because there are insufficient flavours to balance the artificially elevated alcohol.

Question 13

What are 3 forms of stabilisation? Briefly describe.

Answer 13

Tartrate - remove crystals by chilling the wine below 0 C and filtering

Microbiological - wines that have low to medium alcohol, low acidity and a little residual sugar are particularly at risk from yeast or bacterial storage. Careful handling and and addition of SO2 can protect these wines.

Oxygen - risk of oxidation can me minimized by avoiding exposure and topping off SO2

Question 14

What is sulfur dioxide used for in winemaking?

Answer 14

• It acts as an antioxidant and antiseptic

- grapes receive their 1st dose of sulfur dioxide as they arrive at the winery

Question 15

What is protective/anaerobic winemaking? List some methods

Answer 15

Avoiding as much oxygen as possible during winemaking.

• picking at night to keep the grapes cool
• keeping grapes cool during transportation using nitrogen and carbon dioxide
• Using airtight equipment and pumping CO2 and nitrogen

Question 16

What is the yeast species that is responsible for the majority of alcoholic fermentations? Why?

Answer 16

Saccharomyces Cerevisiae

It is tolerant of high alcohol and SO2

Question 17

List 7 important options in white winemaking:

Answer 17

• Skin contact
• Clarity of the juice
• fermentation temperature
• fermentation vessel
• use of lees
• MLF
• maturation options

Question 18

What are the 3 main techniques used for clarification?

Answer 18

• Sedimentation
• Fining
• Filtration

Question 19

What is sedimentation?

Answer 19

Once the gross lees have settled in a deposit (gravity process that is slow), the wine can then be slowly and gently pumped into a different vessel leaving the sediment behind, a process known as racking. The wine will continue to throw a deposit of fine lees during maturation and the clarity of wine can be improved by repeated rackings.

Question 20

What is fining?

Answer 20

This involves adding a fining agent to the wine - a substance that forms bonds with certain wine constituents and causes visible clumps that can be removed by filtering.

Question 21

Name and describe the two forms of filtration.

Answer 21

Depth filtration - filters are made from a thick layer of material. As wine passes through the filter it traps the gross lees.

Surface filtration - filters resemble very fine sieves. The filters are very expensive and clog up very easily, so they are generally used for wines that have already passed through depth filtration. Where the pore size is small enough to remove yeast and bacteria that might still be present, this can be referred to as sterile filtration.

Question 22

What processes do some winemakers feel can negatively affect a wine’s character, particularly it’s texture?

Answer 22

Fining and Filtration

Question 23

What temperature does alcoholic fermentation happen?

Answer 23

5-35 degrees C

Question 24

What are lees? What are the 2 types and their differences?

Answer 24

Dead yeast cells and grape fragments

Gross - larger particles that fall to the bottom of the fermentation tank and can cause unpleasant aromas if not removed

Fine - smaller particles that are sometimes removed during the fermentation process, but may be left in contact during pre bottling maturation in order to add extra flavour and textures to the wine.

Question 25

What is the optimum temperature for white wine fermentation?

Answer 25

between 12-22 degrees C

Question 26

What are the 4 important factors when choosing oak?

Answer 26

• Species and origin of oak
• size (225L barrique - 228L piece - vessels upward of 2000L)
• Age
• Production (level of toasting)

Question 27

What is an inert vessel? Name and describe the 2 kinds most used.

Answer 27

vessels that do not add flavor to wines or allow oxidation.

a) stainless steel - easy to clean and regulate temperature
b) concrete - regulates temperature without the use of expensive equipment

Question 28

What are the 2 important ways which a winemaker can control the fermentation?

Answer 28

-yeast: ambient yeast (bloom) or cultured yeast
-Temperature:
>lower temps encourage fruity flavours and avoids loss of floral notes
>higher temps are necessary for the extraction of colur and tannin

Question 29

What is used to carry out MLF? How can a winemaker avoid MLF (3)?

Answer 29

• Lactic acid bacteria

- storage at cool temps, use of SO2, or filtering out bacteria