Chapter 9 Harvest Flashcards
What factors can be determined by the timing of harvest?
- Levels and nature of the various compounds within the grapes
- Style and quality of the finished wine
How can the ripeness of grapes be defined?
- Sugar levels
- Acidity levels
- Aroma and tannin ripeness
Define Titration
A method of calculating acid levels by gradually adding measured amounts of another substance that reacts in a known way with the acidity.
How can acidity levels be measured?
- Reading the pH level on a pH meter
- Calculating the acid levels using titration
How can aroma and tannin ripeness be measured?
By taste (with experience)
How can sugar levels be measured?
Using a handheld refractometer.
Define machine harvesting
One of the two methods to pick grapes it is the default option for inexpensive to mid price wines and for larger scale production.
Where can machine harvesting be used?
In vineyards that have been designed from the start to allow mechanization: Even row spacing, a turning space at the end of rows and located on flat land or land with a small, regular gradient.
How can the quality of the wine made by machine harvesting be improved?
- Selecting out undesirable fruit by hand before harvesting my machine
- Using newer machine with bow rod shaking method that can be gentler and more selective
- Investing in machines with optical sorting devices, which can crush white grapes and add sulfur to limit oxidation
- Grape sorting on arrival in the winery
What are the advantages of machine harvesting?
- Faster and cheaper in e vineyards. It can be 1/3 of the price of hand harvesting
- Avoids issues of the lack of ability of casual workers
- Grapes can be harvested at night and kept cool which can avoid oxidation in microbial spoilage
- The timing of the harvest can wait until the desire level of ripeness and then be done quickly.
What are the disadvantages of machine harvesting?
- Less gentle than hand harvesting
- Renting or owning a machine is not cost-effective for small vineyards
- Not suitable for vineyards with different grape varieties ripening at different times within the same vineyard
- Not suitable for vineyards in steep slopes or with limited access
- The quality of the work is only as good as the skills of the operator
- The rental of the machine can be a competition, specially at the best moment for harvest
- Purchasing harvester is a major investment
Define hand harvesting
A method of picking grapes, preferred for making premium wines involving a team of harvesters, removing the whole grape bunches from the vines by cutting the stem of each bunch.
What are the advantages of hand harvesting?
- Pickers can be highly selective and remove any disease, under or extra ripe fruit at the point of harvest
- Pickers can deal with steeper slopes, irregular rows, and mixed plantings in the same vineyard
- The crushing of grapes which can lead to oxidation in microbial spoilage can be avoided if pickers use 10 to 15 kg crates
- Can be used for whole bunch pressing / carbonic maceration
- Can be a + for maketing
What are the disadvantages of hand harvesting?
- More expensive than machine in medium to large vineyards
- It requires the availability of the workforce and their training and supervision to ensure that they work to the required standard
- It is difficult to avoid high temperatures and it increases the chances of oxidation and microbial spoilage
When/where is hand harvesting required?
- Wines made by whole bunch pressing (traditional method sparkling and red made with carbonic maceration)
- Wines that require selective harvesting (botrytis affected grapes)
- Vineyards located in steep slopes or uneven land
- Bush vines (machine harvesting needs trellised vineyards)
