The term dry-farmed is most often used by wine producers in wine regions where irrigation is the norm. In general it is a term touted by producers in the new world wine regions like California, Australia, Chile, Argentina etc., where irrigation is totally permitted and indeed often necessary to cultivate grapes.
In contrast, in the 'Old World' vine irrigation has traditionally been forbidden except in extremely hot years, in the first few years of a vine's life, or in experimental vineyards. So while it is rarely 'marketed' as such, most vineyards in Europe are actually dry-farmed.
What's the Deal with Dry-Farmed?
Grapevines, like most plants, need water to survive and grow. However, in order to produce high quality grapes they also need to undergo a certain amount of water stress. Too little water and the vine will not thrive; too much and you get higher yields but more dilute grapes. In an ideal world the annual rainfall will supply enough water for the vines to produce a balanced crop of healthy, concentrated grapes. However, as we all know, rain does not always fall exactly when we need it. In some years we have lots of rain and in other years, it is a virtual drought.
Irrigation is man's way of ensuring the vine gets its fill of water. Dry farming is forcing the vine to work out how to survive in times of water stress. The problem with ongoing irrigation is that the vines become lazy, the roots remain near the soil surface and, by default it becomes dependent on 'man's intervention to feed it water. Additionally, continued and over irrigation leads to higher grape yields, bigger grapes but with less concentrated flavors.
How Dry-Farming Works
Dry farming is a way of forcing the vine to deal with water stress. Dry farming practices force the vines' roots deeper down into the soil, down to the sub-soil layers where it can access water and many of the much-needed minerals and nutrients less available up nearer the soil surface.
Deeply rooted vines are a good thing. The deeper the roots the stronger the vine and the better it can withstand extremes of weather, as well as access the all important nutrients and water. A dry-farmed vine is a more self-sufficient, hardier vine.
If a grape grower wants to change over to dry farming, it is best to first wean the vine off its ever-ready water supply via a system of minimal irrigation, to allow the vines time to build strong roots and burrow deeper into the soil.
Unfortunately, dry farming does not work everywhere. Wine regions like California's Central Valley or Australia's inland Riverland are far too hot and dry to ever enable the vines to self-regulate their water supplies.
Dry-Farmed or Irrigated - Which is Better?
Alas, the situation is not so black and white as to be able to categorically say that dry farming produces the best grapes. It certainly makes for a stronger, sturdier vine, but today's sophisticated irrigation systems are very capable at managing the water supply to a vine, ensuring that the vine's energies are focused on quality rather than quantity berry production.
Mary Gorman-McAdams, MW (Master of Wine), is a New York based wine educator, freelance writer and consultant. In 2012 she was honored as a Dame Chevalier de L'Ordre des Coteaux de Champagne.
Previous Wine Word: Noble Rot
(Image: Underlying image by Sadovnikova Olga/Shutterstock)