The Lowly Grape
In this issue: Why is wine made from grapes and not from oranges?
Wine is one of the oldest processed food items widely available today. Only bread, cheese, olive oil and beer have a recorded history that goes as far back as wine.
Yes, wine was considered a food item for millennia before it became an alcoholic beverage in need of special taxation and regulation. Spread by the Roman Empire from its Mediterranean roots, wine was an important part of European communities through the Middle Ages, when the cultivation of wine grapes started to become specialized. The growth of large communities dependent on stable sources of food also saw the selection of many of the wine grapes we know today. Specific grape varieties were chosen for their affinity to a certain place, climate, and the local food culture.
Why the lowly grape, you ask? Why not peaches, or apples, or oranges? As it happens, ripe grape pulp contains the highest sugar content of any other fruit in nature. At 24% sugar content, grape juice is the sweetest natural juice. Oranges usually reach 8%, and some fruits, like persimmons, can reach 17% only in very warm years. Other common sources of table sugar, like beets, deliver about 17%, whereas sugarcane only contains 10%. Sugarcane is, however, cheap to grow and its sugar is easy to extract.
Nevertheless, sugar content is not the only reason for the choice of the grape in winemaking. In the temperate European climate, grapes grew well in areas not suitable for other types of agriculture and could be dry farmed in hilly terrain above villages. Areas close to rivers and streams, with easy access to water, needed to be used for homes, vegetable gardens and farm animals. Compared to other fruits and vegetables, the grapevine is a perennial plant that needs little care year round.
Grapes are easy to harvest as the vines can be trained so that bunches develop at a desired height, for easy picking. The grape skins are relatively thin and can be easily broken to extract the juice by stomping, or gently pressing. Fill a large container with freshly picked grapes, and the weight alone will squeeze the juice from the berries at the bottom.
The skins are also thin enough to allow grapes to dry out and turn into raisins without having to peel or use any other laborious procedure. The most common way to make raisins still today is to drop the grapes into trays placed between the vine rows and let them dry for two weeks under the sun. Simple, right?
Making wine also provided a way to store liquid in a stable form during winter months, when running water could be scarce. Of course, the sweet grape juice would start fermenting immediately by the ubiquitous yeast that lives on the grape skins. But once fermented, wine is very stable and could be stored for long periods in a closed container in a dark corner, usually an underground cellar.
Although our modern diet typically contains most of the vitamins we need, this was not true for most of human history. Fresh fruits and vegetables were not available in winter and dried fruits, pickles and wine were an important passive source of nutrients during the cold months. Wine was also an important ingredient in cooking, as the alcohol content helped to rid meats and other not-so-fresh ingredients of bacteria noxious to humans. Marinating was not only practical, but also imparted agreeable flavors to a stew.
Although grapes can be eaten raw, different varieties have been selected and cultivated for their affinity to making wine. Table grapes require more water to develop plump juicy berries, tend to have thinner skins, and are seedless most of the time. Wine grapes are smaller with less juice and tend to be harvested at higher sugar levels. Table grapes harvested to make grape juice, for example, are harvested at 15% sugar content. Very ripe grapes are as fragile and difficult to transport as very ripe tomatoes. The grapes you find at the supermarket are most times picked before the were fully ripe so that they can withstand transport.
Wine grapes tend to be small also because they are usually grown under water stress, which results in even smaller berries with a high ratio of skins and seeds to juice. As tannins and color pigments reside in the skins, this ratio is ideal for winemaking, but not for table use. For a long time I believed that wine grapes were inedible! They really aren’t, but you need to discard the bitter skins and seeds. It can become laborious!
Recent DNA studies tell us that all white grapes are descendants of black skinned varieties. We also know that grape vines, produce seeds with low fertility. Even when they germinate, the seedlings are likely to be very different to the parent, as is the case with most fruit bearing plants. This is why vines are propagated from cuttings so that the vineyards can produce grapes with predictable characteristics.
Over thousands of years of cultivation, communities have been selecting those grapevines that grew best in their particular area. Thus the concept of terroir was born.
On the next issue I will be talking about how those grape selections produced styles of wines which are typical of the people and the areas where they were established.
