Scrape it off with a limestone shard you've plucked from one of the ancient crumbling walls. That, too, is terroir. The notion sounds mystical, even a little snooty to American ears. But lately science has been backing it up. Perhaps the issue should have been resolved long ago, but the more we find out about wine, the less we seem to know.
Wine is so much more complicated than orange juice or wheat or other agribusiness products.
When I started doing enology many years ago, people said there were 300 different components to a wine. Today we say there are 10,000. Modern analytical techniques have not only made it possible to detect even trace amounts of those components but, more remarkably, have also made it obvious that humans can smell and taste incredibly tiny quantities. That molecule, trichloranisol, has been extracted and identified. Knowledge of how a wine acquires that mysterious composition is just as sketchy.