The countless varietals of wine grapes created and marketed, including 5,000 for V. vinifera, are different in features like color, size, and shape of the berry, the composition of the juice (including flavor), ripening duration, and resistance to diseases. They are grown in diverse climates, and various processes are used to make wines made from berries. Each of these variations results in a vast selection of available wine.
The species and the varieties
Vitis vinifera, most likely originating from the Caucasus Mountains, is the main winemaking plant, with most of the world’s wines made from the varieties of the kind of plant. V. labrusca, as well as V. rotundifolia, have been domesticated within the east of the United States, the domestication of V. amurensis is confirmed in Japan, and a variety of hybrids between species have been utilized for the production of wine. The high sugar content of many V. vinifera grapes at maturity is the main reason for choosing these types to be used in most of the world’s winemaking. Their sugar content naturally occurs, making them the ideal fermentation material, resulting in an alcohol content of 10 percent or more wine with less alcohol. It tends to be unstable because of its susceptibility to spoilage from bacteria. The moderate acidity of the ripe grapes from the V. vinifera grape varieties is also favorable to winemaking. The fruit is acidic at under one percentage (calculated in tartaric acid, the primary acid found in wine grapes), with a pH range of 3.1 or 3.7 (mildly acid). Malic acid is vital, but only tiny quantities of citric acid are found.
A third reason winemakers are drawn to the wine grape is its wide range concerning its composition. The color patterns of the skin vary from light, greeny-yellow to russet red, pink, blue-black, or reddish violet. The juice is usually colorless, but certain varieties can be red or pink, and the flavor can vary from mild to intensely aromatic (Gewurztraminer and Cabernet Sauvignon Zinfandel). Certain varieties, like Pinot Noir, having rather bland juices, create distinctive flavors after being fermented on skins and matured.
The V species. labrusca and V. rotundifolia do not contain enough natural sugar to make wine with an alcohol level of 10 percent or more, in which case additional sugar is typically required. Their acidity at maturity is usually excessive and has a low pH. The species of this group naturally come with distinct flavors. The flavor of V. labrusca, due to methyl anthranilate and others, can be deemed excessively strong by specific consumers. The taste, particularly prevalent in wines made of Concord-type varieties, is usually described as “foxy.”
Grapes, though primarily a plant in the temperate zone, can be grown in semi-tropical conditions. They’re not adapted to the cooler regions in the location of mild where the growing seasons are too short for the fruit to mature or in areas where low winter temperatures (less than -7°C or 20 deg F(less than -7 degrees Celsius) can endanger the vine or its fruitful buds. V. vinifera is more prone to injury from winter conditions than V. labrusca.
Climate significantly affects the structure of mature wine grapes. The primary reason for the variance in grapes of different regions is the disparity in amounts of heat absorbed from the vines in their period of growth. Other factors to consider are differences in temperature between day and night, hours of sunlight, and soil temperature.
Grapes begin their growing cycle in spring when the temperatures average around 10 degrees Celsius (50 degrees Fahrenheit). To be mature, they require several temperatures above 10 degrees Celsius during this growing time. This quantity of heat, also known as heat summation, is determined by adding the number of degrees of the average daily temperature above 10 degrees Celsius for each day during this growing period. A heat summation of around 1,800deg is needed to ensure successful development. If the summary of heat is lower than the minimum, then the grapes won’t develop; they will be at the close of the season with a lack of sugar and with too excessive acidity. This problem, which is expected within the Eastern United States, Switzerland, and other cool regions, is remedied with the help of adding sugar to crushed wine grapes if the summation of heat is higher than the minimum, like in Algeria and a portion of California where the grapes mature more quickly and have less color and acidity than those that grow under more excellent conditions.
The factors that affect the heat summation in the grapevine and, hence its grape structure comprise the exposure (in Europe, best from the east) and the air drainage (preferably from the slopes towards the valley) as well as the temperature of soil (above 10 degrees Celsius during the season of growth) and the soil moisture content (not dry and not drained for longer than a few minutes).
Conditions during the seasons can also be necessary, especially in areas with low heat summation. This is located in France in France and Germany. If it is the time of year when growth in these regions is warmer than typical, and the fruits are more ripe and balanced, that is what you would expect from cooler months. In warm areas, sweet, sweeter dessert wines can benefit from a slight reduction in summation of heat, resulting in lesser berry rising (moisture disappearance) and more color and acidity that can be achieved if it is boiling.
The cultivation practices such as weeding and pruning could also influence the maturity of the fruit. While the soil’s composition impacts the temperature of the ground and root penetration, as well as the capacity to hold water, power, and nutrition of the vine, its impact on the taste of wines, which differs from region to region, is not fully understood.