Exploring the technique and tradition of food and wine through storytelling

Factors Affecting Grape Growing

Vitis Vinifera can not just be grown anywhere. In the world, the wine regions for vinifera are located between the 30 degree and 50 degree lines of latitude. In this broad span of land, there are a variety of climates and each has a different effect on grape production.

North Carolina, where I am, struggles to produce vinifera for a few reasons. First we have heat spikes throughout the growing season. Next, we have lots of rain that can dilute the sugar content of grapes. Third, our high clay content in soil can prove to be tricky (though there are grapes, like merlot, that enjoy the clay).

Grapes need consistent temperature throughout the growing season. Some rain is necessary, but too much will ruin things. Soil must have good drainage capability for grapes to thrive. Grapes need adequate sunlight. You see why California is such a premier growing region?

Climate. In the most simple form, climates can be warm or cool. Warm climates allow for greater maturation of grapes compared to cold climates. The ripening of a grape starts with a high acid content. As it ripens, the sugar content increases and the acid content decreases. Therefore, warmer climates produce grapes with high sugar and low acid. The inverse, cool climate, produces grapes with low sugar and high acid.

Sugar levels correlate to alcohol levels. A warm climate wine, after fermentation, will have high alcohol and low acid. A cool climate wine will have low alcohol and high acid. There are so many climates on the spectrum that I will make another article exploring the variety.

Bodies of water. Bodies of water are moderators of climate. This means that bodies of water can warm a cool region, or they can cool a warm region. A good gust of wind can aid in this process. Many of the world’s great vineyards are located near water.

Mountains. Mountains can function a few ways to help grape growth. One function is creating a rain shadow. That means that the mountains protect certain areas from rain . For example, Oregon gets a lot of rain, but the rain shadow there allows for excellent wines to be produced in areas like Willamette Valley and Columbia Gorge.

Another function of mountains is to supply elevation so that grapes may grow high enough above sea level to attain the desired temperature. Places in South America, like Argentina, have vineyards growing around 10,000 feet above sea level. This keeps the vineyards safe from temperature spikes by providing a consistent temperature during growing season.

Mountain slopes give a few advantages to grape growing. In Germany, there are vineyards planted on steep slopes in the Mosel Region. These south facing slopes help the grapes get the sun exposure they need which keeps the grapes warm. The slope allows for better drainage, encouraging the roots to dig deep.

Diurnal Shifts. Diurnal shifts are the difference between the daytime high temperature and the night time low temperature. Areas with greater diurnal shifts are better for grape growing. When it gets dark and things cool off, the ripening of the grape stops. This allows the ripening process to be drawn out over a longer period of time. The cool nighttime will allow the grapes to retain some of their acid content which will balance the wine flavor overall.

Negative factors. Frost in the spring can damage new buds. Frost in the fall can damage fruit. Winter freezing can kill the whole vine. When it hails, grape leaves and clusters can get wrecked. Areas prone to strong winds run the risk of vines being blown over and damaged.

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