If you cannot remember the last time you had a glass of organic wine, you are hardly alone. Overall, less than 5 percent of the world’s vineyards are organic. In the United States, the world’s largest consumer of wine, only 1 percent of wine sold by volume was organic. The paltry market for organic wine around the world belies the fact that over the past half century, countless organic winegrowers and vintners have dedicated great effort to creating a larger market for the category, without much success. Meanwhile, plenty of other organic products, including vegetables, milk, and tea, have become widely consumed, at least by affluent, health-conscious city dwellers. Why the difference?