D1.C9. Harvest

Question 1

What was the traditional rule of thumb for estimating ripeness of the grapes?

Answer 1

Grapes ripen 100 days after the beginning of flowering

Question 2

Especially in European regions, readiness for harvest has been measured by which factor?

Answer 2

Potential alcohol levels

Question 3

In cool regions, once potential alcohol has reached to which range, can the grapes could be harvested?

Answer 3

9.5–11% abv
Petit Chablis require a minimum of 9.5%
Chablis requires 10%
Bourgogne Blanc 10.5%.

Question 4

More recently the context for making decisions about harvesting dates has changed due to:

Answer 4

• A generally warmer climate
• Better viticulture, enabling the vine to ripen grapes fully
• A focus on aroma and tannin ripeness

Question 5

Name one climatic threat during harvest period

Answer 5

Rain

Question 6

What are the adverse effects of rain in the last days prior to harvest?

Answer 6

• Dilution of grape juice
• Splitting of the skins with consequent threat of grey rot

Question 7

Name the criteria for measuring ripeness?

Answer 7

• Sugar levels
• Acidity levels
• Aroma and tannin ripeness

Question 8

How is the sugar level measured?

Answer 8

Handheld refractometer

Question 9

Most dry still wines are harvested between what Brix levels?

Answer 9

19° and 25°, which will convert into 11–15% abv

Question 10

How is acidity measured?

Answer 10

• Titration can be used to calculate acid levels
• pH of the juice can be read by a pH meter

Question 11

How is aroma and tannin ripeness measured?

Answer 11

By tasting

Question 12

What is the most important way of deciding, when to harvest?

Answer 12

Tasting the grapes

Question 13

How does the style of the wine affect the harvest date?

Answer 13

• Chenin Blanc can be harvested over a period of 4-6 weeks
  + Early for sparkling wine
  + Mid-harvest for dry and off-dry styles
  + Late for botrytis or late-harvest styles
• Zinfandel
  + In early to mid-August for White Zinfandel
  + In September for red wine
• The grapes for botrytised wines often need hand-harvesting over several passes
• For Icewine, grapes can only be picked when temperatures reach below certain levels
  (e.g. below -8°C / 18°F for Canadian Icewine)

Question 14

What are the risks for extended hang time for the grapes?

Answer 14

• Overly alcoholic and unbalanced wines
• Low in natural acidity
• Extra-ripe fruit character.

Question 15

Machine harvesting has become the default option for which types of producers? Which country is an exception?

Answer 15

• For larger-scale producers, making inexpensive to mid-priced wines
• South Africa (due to availability of labour at a low cost)

Question 16

How can the quality of the machine harvested grapes be improved?

Answer 16

• Selecting out undesirable fruit by hand before harvesting by machine
• Using a bow-rod shaking machine
• Using latest machines that have options for optical sorting devices
• Rigorous sorting on arrival in the winery, including removal of MOG

Question 17

What are the advantages of machine-harvesting?

Answer 17

• Faster and cheaper
• Avoids issues of the lack of availability of, and possible unreliability among, casual workers
• Grapes can be harvested at night
  + Reduce microbial spoilage and oxidation
  + Saves the cost of refrigeration
• The timing of the harvest can wait until the desired level of ripeness has been achieved and then carried out quickly

Question 18

What are the disadvantages of machine-harvesting?

Answer 18

• Less gentle
• Not cost-effective for small vineyards
• Unsuitable for grape growers that have several different
  varieties ripening at different times in the same plot
• Not suitable for vineyards on steep slopes or with limited access
• The quality of the work is only as good as the skills of the operator
• There may be competition for the rental of the machine at the best moment for harvest
• Purchasing a harvester is a major investment

Question 19

When hand-harvesting is usually preferred?

Answer 19

For producing premium wines

Question 20

What are the advantages of hand-harvesting?

Answer 20

• Highly selective
• Suitable for steeper slopes, irregular rows and mixed plantings
• If handled with care and put in small, stackable crates (with a maximum weight of 10–15 kilos), the crushing of grapes and the release of juice, which would then be prone tooxidization and to microbial spoilage, can be avoided

Question 21

What are the disadvantages of hand-harvesting?

Answer 21

• Expensive
• It requires the availability of a reliable work force and their training and supervision to ensure that they work to the required standard
• Harvest is carried out in daylight hours and may not be able to avoid high temperatures

Question 22

When is hand-harvested required?

Answer 22

• Style
  + Whole bunch pressing (Champagne, Beaujolais)
  + Selective harvesting (Trockenbeerenauslese)
• Geography: Douro Valley, Mosel
• Vine training: Bush vines