What are biodynamic wine grapes?

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Dear Dr. Vinny,
What are biodynamic wine grapes?
—T, New York
Dear T,
Biodynamic farming is a method similar to organic farming, in the sense that both forbid the use of synthetic chemicals, but biodynamic farming has additional requirements.
Biodynamics looks at the whole farm, creating a self-sustaining ecosystem by incorporating practices such as cover crops, composting, the use of livestock and natural methods of pest control. (Many organic growers do these things too; they're just not required for the USDA Organic certification.) The system is particularly known for requiring the use of nine preparations, made from herbs, minerals and manure, in field sprays and compost additions to encourage soil and plant health. If a grower is following all the principles, they also time certain activities, such as pruning and application of the preparations, to the astronomical calendar and lunar cycles.
Unlike with organic farming, the U.S. government does not regulate biodynamically farmed properties or produce; the independent, non-profit Demeter Association oversees that certification, which is approved for use on U.S. wine labels. To earn certification, biodynamic farms must set aside 10 percent of their land for biodiversity.
A wine can be “made from biodynamic grapes,” meaning the grapes were grown to the specific farming practices outlined by Demeter. A “biodynamic wine” means that not only were the grapes farmed biodynamically, but also the wine doesn’t have any manipulations such as yeast additions or acidity adjustments.
And like organic certifications, biodynamic farming isn’t a guarantee of quality, but it does mean that a lot of effort was put into it.
—Dr. Vinny