Definition - What does Altitude mean?
In the context of viticulture, altitude is a geographical vertical measurement of the distance of the vineyard from sea level. The altitude of the vineyard can affect the growing season of the grapes due to many different environmental variables. While there are both benefits and risks involved with higher altitudes and viticulture, vineyards exist at sea level all the way above 9,000 feet, with Salta and Mendoza, Argentina being some of the highest vineyard regions in the world.
WineFrog explains Altitude
The altitude of the vineyard plays an important role in how the grapes grow and ripen and in how they taste. Wine grapes grown at higher elevations have higher levels of more rounded tannins and a more favorable phenolic profile, this is thought to be due to the higher light intensity and higher UV rays at higher altitudes. Other beneficial factors at high altitude include; lower temperatures and lower levels of oxygen and carbon dioxide.
While growing seasons can be shorter, high-elevation vineyards have elevated rates of photosynthesis due to the higher UV radiation. Risks that viticulturists must deal with include: early frosts, extreme weather, erosions, uneven and variable soil type and quality, these risks can lead to higher vineyard management costs and lower yields at harvest.