"Can I ask a stupid question?" Ah, everyone's favorite opening. And as a teacher, I'm supposed to say there are no stupid questions. But I was prepared for one when our friend Will opened with that earlier this month. His question, however, was far from stupid: "What, exactly, is the deal with wines labeled 'old vine'?"

Yes, what IS the deal with that? It appears on a fair number of bottles these days, often without descriptor. And it does seem like the thing that would be stupid to ask, so people don't.

Bottles marked in some way as "old vine" contain vino made with, well, grapes from vines that are old. Sometimes really, really old. Interestingly enough, there's not an industry standard for what designates calling something "old vine," but generally you can count on the grapes coming from vines at least 30 years old, and often they're more than twice that age. The vines are gnarly and thick by that time (we have an old vine carcass on our store patio if you want to take a peek)—a truly distinct look.

Once vines hit a certain point (around 20 years), the older they get, their yields decrease. Because of this, at a certain stage, many vineyards will tear them out and replace them with new vines. Why get 25 hectoliters of grapes per hectare when you can get 50? (Grape yields are measured in hectoliters per hectare in most of Europe, but often in tons per acres in the U.S.) But the reason some vineyards hold onto those old vines is their potential.

The neat thing about old vines, you see, is while they produce significantly fewer usable grapes, they tend to produce grapes that are much more intense and concentrated. So while a winemaker won't get nearly as many bottles out of them, the bottles they do get are often more interesting, deep, and complex. They're also, due to the loss the vineyard takes on not getting to sell as many bottles, often more expensive. You'll see this particularly with French wines. But there are some great budget old vine wines out there, especially from California and Spain. I love, for instance, Cline's "Ancient Vine" line (they have a Zin, Mourvedre, and a Carignane), which all retail for around $15 or less.

Buying an old vine wine doesn't guarantee your wine will be great, but they're fun to explore. So no stupid questions around here. If you think you have one, let me know and I'll try to dispel your worries.