13.2 & 13.3 General Winemaking Options: Transportation and Grape Reception

Question 1

Explain methods for transporting hand-harvested grapes to the winery from the vineyard?

Answer 1

1. Small Crates 2. Large hoppers (bins)
   - Small crates prevent the grapes from being crushed which makes them more vulnerable to oxidation, and spoilage organisms
   - Small crates are used if whole bunches are desired or premium wine to be produced
   - Large hoppers (bins) result in some grapes being crushed so to protect them so2 should be applied.

Question 2

How are machine-harvested grapes typically transported?

Answer 2

• already been destemmed - larger containers with some release of juice - might add SO2 at this point (typical of larger estates)

Question 3

After grapes are picked, what vulnerabilities are exposed? What conditions worsen these vulnerabilities?

Answer 3

The grapes are vulnerable to

• oxidation
• ambient yeasts
• acetic acid bacteria (turns alcohol to acetic acid (vinegar))
• The above is accelerated at higher temperatures

Question 4

Why are black grapes less vulnerable to oxidation after harvest?

Answer 4

• They contain more phenolic compounds that have anti-oxidative properties

Question 5

What 4 measures can be taken to minimise the threat of oxidation or microbial spoilage during transportation of picked grapes?

Answer 5

Harvesting grapes at night /early morningwhen temperatures are lower

Addition of SO2 for its anti-oxidant and anti-microbial properties

Keep the grapes cool - cold storage upon reception

Sanitising harvesting equipment/bins.

Question 6

What factors are at play when it comes to reception of the grapes at the winery?

Answer 6

• the volume of the grapes - whether they have been hand- or machine-harvested - the health and quality of the grapes

Question 7

Explain how large volumes vs small volumes of grapes are moved through the reception process

Answer 7

Large volume

-conveyor belt for destemming and crushing if not already done by harvester.

Small volume or hand harvest

• crates moved by forklift / conveyor, to sorter, then to destemm, then to crush (sometimes destemm and crush done together)

Question 8

Why might a winemaker choose to chill the grapes on reception?

Answer 8

• If the grapes are warm when they reach the winery
• decreases rate of oxidation
• preserves fruity aromas
• reduces microbial spoilage
• Adds cost and unlikely to be done for high vol inexp wine prod.*

Question 9

How might whole bunches of grapes be chilled?

Answer 9

• a refrigeration unit (slower)
• a heat exchanger (if the grapes are in a more fluid format (e.g. fruit that has been machine picked, grapes that are destemmed and possibly crushed) (quicker) and more expensive

Question 10

What is the French word for grape sorting?

Answer 10

Triage

Question 11

What factors is the level of grape sorting dependent on?

Answer 11

most mechanically harvested grapes will not be sorted

the intended final wine quality and price

whether any sorting has been carried out in the vineyard (e.g. by skilled hand-pickers)

the physical state of the grapes (if grapes arrive in large containers, the bottom grapes will have crushed and released juice; this is too liquid to sort)

ripeness and health of the fruit arriving at the winery:

• poor vintages= greater of level of sorting to remove mouldy and under-ripe grapes. (except in most basic Q wine)
• In good years - min sorting - just MOG

Question 12

Why is sorting costly?

Answer 12

• labour cost - time taken for meticulous hand sorting
• greater scrutiny often results in less yield

Question 13

What is MOG?

Answer 13

Material other than grapes - Examples: leaves, twigs, insects, etc.

Question 14

Name 3 sorting options for quality wines.

Answer 14

1. Removing unwanted grapes/bunches before picking or during hand-harvesting
2. Sorting by hand on a table or a moving or vibrating belt (the latter also removes MOG); this can take place before or after destemming, or occasionally both before and after destemming
3. Optical sorting - High-tech, high-cost option, uses digital imaging and software technology to scan individual grapes and selects those that match a reference sample and any MOG.- Example: Grand Cru Classé estates in Bordeaux

Question 15

What types of grapes need to be destemmed upon arrival at the winery?

Why is this done?

Answer 15

• Hand-harvest grapes - most whites - many reds
• this avoids the bitter oils and tannins found in the stems influencing the delicate flavours of the wine.
• Many mechanical harvesters destem at picking.*

Question 16

How do destemmers work?

Answer 16

• a series of blades within a rotating drum that remove the grapes from the stems

Question 17

Give 3 examples in which grapes are not destemmed purposefully.

Answer 17

1. red wine fermentations that use some whole bunches (e.g. with Pinot Noir in Burgundy or Sonoma)
2. carbonic maceration (e.g. with Gamay in Beaujolais)
3. whole bunch pressing for some white wines (e.g. common for high-quality sparkling wine).

Question 18

What is crushing?

Answer 18

The application of sufficient pressure to break the grape skins and release the juice, making it available for fermentation.

Often combined with destemming in the winery.

Question 19

What is extremely important during crushing?

Answer 19

The pressure applied is gentle enough not to crush the seeds, which would add bitterness

Question 20

What is must?

Answer 20

• The mixture of grape juice, that is to be fermented.