Other Cards

Question 1

2 causes of cloudiness / haze and remedy for each

Answer 1

1/ Growth of yeast or bacteria in wine coupled with failure to filter adequately.

• Better hygiene in the winery
• Pre-bottling chemical analysis and, as necessary
• Filtering wine to remove yeast or bacteria before bottling
• Filter properly (e.g. don’t pump wine at too high a pressure through a depth filter so that some unwanted molecules pass through the filter).

2/ Protein haze where fining is not effective, where the wrong type of fining agent has been used or the wine has been over-fined

• Remedy is to fine correctly and conduct analysis after fining

Question 2

Name 4 things soil structure influences

Answer 2

Root penetration
Water drainage
Nutrient holding capacity
Workability

Question 3

3 types of soils that are beneficial for temperature and sunlight and why

Answer 3

• Light color soils reflect solar radiation into lower part of canopy
• Dark colour soils absorb energy and release later (e.g. night)
• Stony soils same as above

Question 4

6 Factors that can effect availability of nutrients

Answer 4

• Water availability in soil
• Soil PH - e.g Iron hard at high PH, phosphorus hard at low PH
• Presence of living organisms to convert organic matter
• Soil texture (e.g. clay = more holding)
• Presence of humus
• Slopes

Question 5

3 aims of precision viticulture

Answer 5

• Quality and yield
• Reduce environmental impact
• Reduce costs on treatments

Question 6

What is humus?

Answer 6

Organic matter formed by the partial decomposition of plant material by soil microbes and earthworms

Question 7

What are the properties of soil with good structure?

Answer 7

• Sufficient water holding capacity
• Sufficient Oxygen
• Ability to resist erosion
• Allows roots to penetrate to sufficient depth

Question 8

Why is the amount of organic matter and humus in soil important?

Answer 8

Decomposing organic matter supplies nutrients, and humus improves the structure of soil and its water-holding capacity

Question 9

Why is the number of living organisms in the soil important?

Answer 9

Earthworms and microbes break down organic matter into humus and inorganic nutrients that are accessible to the vine

Question 10

What are the advantages of retaining solids in white wine must (1-2%)? What type of wine might it be useful for?

Answer 10

-Texture / Subtle Astringency (skin & stem will add tannin)
-Greater range of fermentation aromas
-Needs careful monitoring and management. Compounds can lead to off-flavours (e.g. reductive sulfur)

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Question 11

What are the advantages for low levels of solids? What type of wine might it be suitable for?

Answer 11

• Keeps fruity aromas
• Low levels provide nutrients for yeasts but need to be carefully managed also if too low (stuck ferment)

Question 12

How can a winemaker achieve levels of solid below 1% in must?

Answer 12

Centrifugation
Pectolytic Enzymes

Question 13

Why is pre-filling analysis carried out before packaging?

Answer 13

Check wine is:
- Stable
- Meets tech spec set by winemaker or client
- Conforms to required legal standards e.g. SO2, trace metals

Question 14

Why does the cap need to be managed?

Answer 14

• Skins would always spend time in same liquid
• Bacteria would convert into acetic acid
• Aerates the must avoiding reductive sulfur compounds
• Distributes heat

Question 15

What is a technical spec?

Answer 15

A list of the wine’s main measurable chemical paramters. If made for a retailed. it’ll form part of the purchasing contract