In the world of oenophiles, terroir is a sacred term. It’s a French word with a murky English definition, but it’s generally used to describe the relationship between a wine and the geographical place that it comes from. Chablis, for example, is renown for its hint of flint, which is supposedly a side-effect of the limestone beds in which the grapes are grown. Terroir is used to explain why genetically identical grape varietals (Chardonnay, Cabernet, Sangiovese) can taste so different in different locations. Grapes express the earth like oysters express the sea.
But is terroir a scientific concept? In a fascinating article, Harold McGee and Daniel Patterson put this romantic myth to the empirical test:
Researchers in Spain recently compared wines from the same clone of grenache grafted on the same rootstock, harvested and vinified in exactly the same way, but grown in two vineyards 1,600 feet apart, one with a soil significantly richer in potassium, calcium and nitrogen. The wines from the mineral-rich soil were higher in apparent density, alcohol and ripe-raisiny aromas; wines from the poorer soil were higher in acid, astringency and applelike aromas. The different soils produced different flavors, but they were flavors of fruit and of the yeast fermentation. What about the flavors of soil and granite and limestone that wine experts describe as minerality — a term oddly missing from most formal treatises on wine flavor? Do they really go straight from the earth to the wine to the discerning palate?
I’m still surprised no one has used DNA chip technology to measure the differences in gene expression between a Chardonnay grown in some expensive region of Burgundy and an identical Chardonnay grape grown in the Central Valley of California. Once those differences in gene expression are identified then owning the expensive real estate becomes unnecessary: with a little genetic modification, a Chassagne-Montrachet can be grown in North Dakota. You just have to turn on the right genes at the right time. Terroir will have been decoded.
But let’s be honest: terroir isn’t really about the taste. It’s about the label. Terroir is really a justification of snobbery. At its core, the claim of terroir is that each grape varietal finds its peak expression in a specific area of (usually French) geography. That strikes me as evolutionarily unlikely. What is far more likely is that the “quality” of a wine is largely determined by our expectations, and we expect a fancy White Burgundy to taste “better” than some plonk from Australia. We justify this perceived difference in quality by referencing the mysteriousness of terroir. If we could genetically duplicate fancy wines in greenhouses, so that terroir was no longer a scientifically valid claim, then people would find some other reason to distinguish between Romanee-Conti and genetically engineered Gallo Hearty Burgundy.
As I’ve noted before, I’m skeptical of our ability to distinguish between the minute molecular differences in different bottles of wine.* Take the following two experiments performed by Frederic Brochet, of the University of Bordeaux. In the first test, Brochet invited 57 wine experts and asked them to give their impressions of what looked like two glasses of red and white wine. The wines were actually the same white wine, one of which had been tinted red with food coloring. But that didn’t stop the experts from describing the “red” wine in language typically used to describe red wines. One expert praised its “jamminess,” while another enjoyed its “crushed red fruit.” Not a single one noticed it was actually a white wine.
The second test Brochet conducted was even more damning. He took a middling Bordeaux and served it in two different bottles. One bottle was a fancy grand-cru. The other bottle was an ordinary vin du table. Despite the fact that they were actually being served the exact same wine, the experts gave the differently labeled bottles nearly opposite ratings. The grand cru was “agreeable, woody, complex, balanced and rounded,” while the vin du table was “weak, short, light, flat and faulty”. Forty experts said the wine with the fancy label was worth drinking, while only 12 said the cheap wine was.
What these wine experiments illuminate is the omnipresence of subjectivity. When we take a sip of wine, we don’t taste the wine first, and the cheapness or redness second. We taste everything all at once, in a single gulp of thiswineisred, or thiswineisexpensive. As a result, the wine “experts” sincerely believed that the white wine was red, and that the cheap wine was expensive. And while they were pitifully mistaken, their mistakes weren’t entirely their fault. Our brain has been designed to believe itself, wired so that our prejudices feel like facts, our opinions indistinguishable from the actual sensation. If we think a wine is cheap, it will taste cheap. And if we think we are tasting a grand cru, then we will taste a grand cru. Our senses are vague in their instructions, and we parse their suggestions based upon whatever other knowledge we can summon to the surface. As Brochet himself notes, our expectations of what the wine will taste like “can be much more powerful in determining how you taste a wine than the actual physical qualities of the wine itself.”
I discuss the Brochet experiments and the power of subjectivity at length in my forthcoming book, Proust Was A Neuroscientist.
*Two caveats. First of all, I believe that there are experts, like Robert Parker, who can distinguish between hundreds of similar wines. Secondly, I’m not saying that all wine tastes the same, or is worth the same amount. I believe there is a big difference between $5 jug wine and a nice $15 Beaujolais-Villages. There is much less difference between that Beaujolais and $100 bottle of fancy Burgundy. In my opinion, wine is a perfect example of rapidly diminishing returns.