Leaf Development : As soon as bud burst occurs, the vine initiates leaf development that allows the vine to begin generating its own energy via photosynthesis. The next part of the process involves: flowering, pollination and berry set. Fruit Development : During the first stage of fruit development the grape berries are small, hard and green. They contain large amounts of acid, but little sugar or flavour. As the summer months pass, the grapes grow larger and sweeter.
W INE F UNDAMENTALS : S TUDY G UIDE © Le Cordon Bleu 19 | P a g e Veraison : This is the point where the grape berries stop growing, and instead begin to ripen. Veraison is marked by a change in the grape’s colour: red grapes begin to darken, and white grapes turn from green to golden. After veraison the following occurs: cell division ceases, and there is a rapid uptake of water, which results in cell expansion. Acids, particularly malic acid, are translocated resulting in a drop in total acidity. Sugar accumulation in the berry commences. At this point, the viticulturist will closely monitor sugar levels in order to determine the date of harvest. Dormancy : After harvest, the vines continue producing starches that are stored in the trunk and roots. As the temperature drops, the vine’s leaves turn golden and brown and slowly drop off. When the mean daily temperature falls below 10°C, the vines enter a period of dormancy. At this point, the vine may be pruned to prepare for the following spring. How is Wine Made? As we learned at the very beginning of this course, wine is a fairly simple beverage - yeast invades grape juice and converts the sugars into alcohol. In ancient times, wine more or less made itself using precisely this simple reaction. If left long enough, pressed grapes would attract wild yeast in the environment, causing a sporadic fermentation. The results, more likely than not, would have been a hazy, vinegar- like solution – quite unpleasant to today’s palate. With little protection against oxidation, and virtually no temperature control, ancient wines would have been susceptible to a number of flaws and bacterial infections. Modern winemaking, however, is a complex science, just as viticulture is. Long gone are the days of foot stomping and open-topped barrels. A modern winery is more like a laboratory. From the moment the viticulturist drops the harvested grapes off at the winery door, the winemaker has a number of procedures to follow, with a multitude variations permitted at each step of the process. Just as the viticulturist chose where to plant, what to plant, how to prune and train, when to harvest, etc., the modern winemaker can choose to manipulate the wine according to his or her wishes.
W INE F UNDAMENTALS : S TUDY G UIDE © Le Cordon Bleu 20 | P a g e A Simple Winemaking Flow Chart 1. Crush and de-stem the grapes 2. Add sulphur dioxide and yeast (optional) 3. Ferment the grape juice (White Wine) or grape juice and skins (Red Wine) 4. Malo-lactic fermentation (optional) 5. Lees stirring (optional) 6. Racking 7. Stabilise and clarify the wine
- Spring '16
- Eric Tobin
- The Bible, Wine Institute, Australian Wine Guide, STUDY WINE