It’s not easy to translate sensation into words, but sommeliers, retailers and wine critics are under constant pressure to do it. The result is that much of the rhetoric around wine is fanciful and frankly useless.

But there’s no getting around the fact that wine presents us with a kaleidoscope of sensory impressions that we recognize from elsewhere. And sharing the experience of them requires that we find a common, meaningful language.

To do that, we must understand why wines taste as they do. There are plenty of fanciful explanations for this. One vintner told me that the whiff of lavender in his wines came from a field of the aromatic shrub abutting his vineyard.

Not likely. Flavors in wines come down to chemical compounds. So when a wine wafts notes of green pepper or buckwheat honey, it's not because the wines had any proximity to them. It's because the same compounds that give those foods their distinctive flavors also are present in the wine.

Environmental factors can play a role (smoke from a nearby fire has been known to cling to grapes and later appear in wine made from them). But generally, the flavors and aromas in wine come from the biology of the vine itself (primary); chemical processes of fermentation (secondary); and aging (tertiary).

Primary flavors are contributed by fruit alone. Their character is determined by the particular grape variety or varieties, the level of ripeness at harvest, and where it was grown. So if you’re tasting a wine made from the sauvignon blanc varietal, you might detect flavors that remind you of grass, citrus rind or oregano. Why? Because the same organic compounds are present in all of them.

Whole new waves of flavor are unleashed as grape juice is subjected to the work of yeasts and bacteria during fermentation. Those fumey, flinty, stony aromas so typical in Chablis and that were once thought to have their source in the region’s chalky soils? Sulfur compounds generated in the fermentation tank.

Further changes occur as wine rests in tank or barrel, waiting to be bottled. For example, a spontaneous process known as malolactic fermentation, if allowed to proceed, converts sharp green apple-like acids into softer, more agreeable lactic acids. New or newish oak barrels may add spice or vanilla notes.

Inexpensive, mass-produced wines focus exclusively on primary fruit flavors. Quality wines always aim for a more complex, nuanced presentation. Just knowing that these three main sources underlie the sensory characteristics of wine is sure to make you a more attentive and appreciative taster—and give you an edge next time you find yourself sparring with a condescending sommelier.