Effects of High Elevation

We often hear about grapes grown at high elevation. Bottles, often those from Chile and Argentina, well up the slopes of mountains in the Andes frequently tout that altitude. Great! Who cares? Likely you and I should.

If you read through this blog, you'll often see that wines come from a variety of valleys. That doesn't mean that they are literally grown in a valley, but they are grown in a region called a valley. What this means almost without exception is that the region is characterized by one or more rivers and often by lakes as well. And, the more proximate an area is to water, the more likely it is to have morning and or evening fog. And, fog cools.

But, at high elevation, it's likely that the grapes are above the fogline. So, they don't get much of the cooling act of the fog. In fact, the fog shields those grapes from what is going on closer to sea level.

Perhaps you are a skier. I'm not, but I know about the part I am about to talk about. Spend a beautiful day out on the slopes for spring skiing. Any exposed skin is likely to get sunburnt. Badly. The higher you go in the mountains, the more direct and closer access you have to sunlight. 

Well, so do grapes. And intense sunlight stresses the grapes. And, unless we're really up too high, and perhaps lasting for only a few hours during the brightest sunshine, it might get quite warm during the summer. But, at night, the sunlight is gone and the temperature cools off quickly. That is the diurnal temperature change we spoke of yesterday. We now know that it tends to result in balanced wines.

But, we always seem to think of wines from grapes grown at high elevation as being particularly big and bold. How is that?

At higher elevation, on mountain slopes, soil tends to be sparser as winter rains will have caused runoff. Nutrients have often washed away. Water has passed by moving down the mountain. Starved, the grapevines need to work hard to get enough water and nutrients to thrive. They spend so much energy searching for that water and those nutrients that they tend to stay small. And concentrated. Those flavors are concentrated. And to survive as small grapes, they grow thicker skins. In thick skins, there are tannins.

So, while it might be more difficult to tend to grapes on steep slopes at high elevations, it is natural that the grapes have characteristics that are very desireable in particularly red Bordeaux grapes.