Wine Terms: "Old Vines"

Who isn’t seduced by the idea that things get better with age?
Contrary to the cliché, most wine is intended to be consumed in its youth – it does not get better with age.
What about the vines which produce that wine?

You’ll certainly see “old vines” (or, in French, “vieille vignes”) printed on lots of wine labels.
Do old vines really produce better wines?... and why?

The short – but unhelpful – answer: sometimes, yes.

The detailed answers are out in the vineyard.
Yields are a very important factor in producing quality wine. Its easiest to imagine that each vine has a limited amount of “essence” to distribute between all the grapes it produces. Young vines are capable of producing masses of grapes, but the resulting juice will be dilute. Old vines, fatigued or wise, naturally produce less fruit. This juice will be more concentrated.
This, however, assumes that the vigour of young vines has been left unchecked. With vineyard efforts like severe pruning and green harvesting (removing of surplus bunches of immature grapes), yields can be controlled and concentrated juice produced from the final harvest.
Alternatively technology (reverse osmosis machines, for example) can be called in to concentrate otherwise dilute juice.

Call me a fuddy-duddy but I doubt concentration could produce anything better than passable plonk. Wines for younger vines, farmed with their yield severely and skillfully restrained, are certainly capable of being at least superb.

Some argue that restrained young vines can produce a wine just as great as old vines. Maybe, but its more complicated still.
Old vines have very deep root system. This means that their fruit production will suffer less during a drought. This is also true during a heavy rain which is more likely to harm young vines with shallow roots.
All this applies to dry farmed vineyards. Irrigated vines show less contrast between young and old vines.

Old vines are almost certainly located in excellent locations (terroir). Many (very) old vines have survived epidemics like phyloxera (a louse which kills vines by nibbling on their roots). They are much more likely to have done so in sandy or very rocky soil (which are inhospitable to pests like phyloxera). Conveniently, these are terrific grape-growing soils.

Finally, the quality of “old vines” wines is often a self-fulfilling profecy. Gnarled old vines are treasured by many vineyards. Often, they are tended with great care, their fruit is gently (hand) harvested, and wines made with exceptional care. In these ways an “old vines” wine may become rather like a “reserve” wine. (It is not uncommon for an estate to make a regular and an “old vines” cuvee).
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So, how old are “old vines”?
Ah, here’s a rub...
There is no legal definition at all.

In very general terms:
At about 35-40 years old, vines – their yields declining – are no longer profitable for making less-than-premium wines. In most cases, these vines are grubbed up and replanted.
It seems sensible to me, then, that vines older than 40 years might be classified as “old vines”.
Sensible, unless my vineyard contains 150 year old vines.

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Here are two examples of “Old Vines” wines available here in Ontario:


Dead Arm Shiraz $55
If you like your Shiraz brawny, muscular or burly, this may be a wine for you. “Dead Arm” is the common name for a vine disease (Eutypa Lata) which often afflicts old vines. Old vines have, inevitably, survived a disease or two... but Eutypa Lata (which kills off sections of vine – not unlike pruning by disease, rather than shears) suits the old-vines idea. That is, of course, assuming it isn’t fatal.
A word of caution: this wine has developed something of a cult following. Undoubtedly, some of the $55 price tag is due to this status.

Bouscasse Old Vines $38
This wine might have been called “Reserve” instead (indeed, its not uncommon for these two categories to overlap).
(1)Yes, it is produced from old(er)-vine grapes.
(2)The regular Bouscasse bottling, is softened by blending Merlot and Cabernet Franc into the Tannat (the dominate local variety... typically as tannic as its name suggests). In contrast, the “Old Vines” cuvee is 100% Tannat, and certainly intended as a vin de garde (to be aged for years in bottle).