It has become a part of the wine expectations in much the same way as ‘miles-per-gallon’ and crash test ratings have with respect to cars.  We’re talking about yields, the amount of grapes or potential wine that comes from a particular agricultural measurement, be that acres in the U.S.A. or hectares (the equivalent of 2.47 acres) in most of the rest of the world.  As most of us have learned via some of the more technically oriented media, low yields are good.  Less grapes on the vine means the vine has less fruit to ripen. The plant can do better when the crop load is lower and it can concentrate its energy on less fruit.  Logical right? 

Is all that true?  Does less fruit mean better fruit?  Well, to a point, yes.  Fruit from smaller crop-loads should be richer, more concentrated, and have more extract, thus theoretically capable of making better wine.  That is the message that everybody preaches in the wine world and we are not here to call question to that particular ‘metric’.  For the most part that is true.  Richer grapes, presuming the same winemaking regimen and oak treatment (both ‘post-harvest’ decisions), will make better, more concentrated wine.  The thing is that the information, which we consider important, comes in a proportionate way.  Usually yields are expressed in ‘tons-per-acre’ or ‘hectoliters-per-hectare’.  

Now we are not here to change how the wine world communicates.  We use such information regarding specific wine write-ups all the time.  There are very few cases where low yields are a bad thing.  But it is also true that while yield information is important and meaningful, there are a few holes in the system that can greatly alter what those ‘tons-per-acre’ or ‘hectoliters-per-hectare’ numbers actually mean. 

There are factors that tons-per-acre statements don’t account for.  For example, when one speaks of tons-per-acre, wouldn’t it be relevant how many vines were planted on that acre? Vine spacing is a fertile subject among growers, with the range of vines per acre generally running from 600 to 2000 vines per acre.  Without being a math genius, you can see that is a pretty substantial spread of vines-per-acre which would directly affect the tonnage harvested.  Logically, 600 vines per acre would give you less tonnage.  But the 2000 plant-per-acre vineyard is clearly more densely planted, and because there are more plants competing for water and nutrients, yield per vine can actually be lower (hence potentially better fruit) even though the ton-per-acre will be higher.

At the heart of this issue, we want people to be comfortable that this information has value.  This isn’t one of our ‘conspiracy theory’ rants.  But, to make an absurd comparison, you could have one plot that has 2000 vines on it that are manicured perfectly to yield one or two bunches per vine, and you could have another plot that has only ten vines that are completely loaded.  The grapes themselves are almost always going to be better in the densely planted vineyard though clearly the 10-vine plot will have an absurdly low per-acre yield.   The point is that yields are good information about a particular wine, but they don’t tell the whole story. 

Let’s take a couple of examples.  Red wines from Priorat, Spain are very concentrated as a function of their older vines planted in rocky slate hillsides. This causes the vines to work very hard and keeps yields on the lower side naturally.  But most of the best vineyards are in really rugged terrain where a large number of plants could not sustain themselves.  It is not unusual to see gaps in the plantings where vines, literally, died.  Yields are naturally low here, yes, in some cases almost to the point of silliness (like 1 ton per acre or less), simply because there are fewer vines within a given space.

On the other hand, let’s take Napa Valley.  Simple economics would dictate that, given the high cost of vineyard land, the more fruit you can get off of an acre, the better.  We know people that have admitted to harvesting six to eight tons off some plots.  Dense planting?  Well in that case they would have to be so dense no one could actually walk between the rows.  That is simply too heavy a crop.  But in a typical, well maintained high density planting, it’s not unusual to get 3-4 tons.  That doesn’t sound super low, particularly compared to some of the wildly low numbers we see from Priorat. But if it’s a high density planting, those numbers are certainly very responsible, and the fruit is plenty concentrated.

The use of metrics such as ‘yield’ is a good barometer for consumers.  Usually those numbers only get brought up as a positive to underscore that a wine’s concentration and richness is the result of concentration on the vine.  The guys harvesting 8 tons per acre aren’t bringing yields up at all as it doesn’t help their case.  So knowing a wine was harvested at a low crop is typically a good thing. 

Consumers (well everyone actually) would like a simple, easy-to-digest, immutable rule regarding aspects of a bottle of wine, a restaurant, or a movie.  Overtly direct, one-size-fits-all explanations make everyone’s life easier, except that it doesn’t usually work that way in the world (or with wine).  When we were learning about wine, folks would make speciously bold claims like ‘Beaujolais doesn’t age’.  The real truth was that Nouveau Beaujolais aren’t built for aging, but a lot of Cru Beaujolais like Morgon and Moulin-A-Vent age quite nicely for a decade or more. 

People also find it pleasing to hear that a vintage is good, unequivocally.  How are the 2010 Bordeaux?  A great, structured vintage.  Plain and simple…This was actually true and got people genuinely excited.  On the other hand: How were the 1998 Bordeaux?  Well, the Right Bank was hugely successful, as was Pessac, but the Left Bank had some late rains that made the success rate a bit more varied.  “Too many words! My tummy hurts now L”. It’s easier for folks, and for us, to have it succinct and positive, it just isn’t always the truth.

So if you want to simply accept that lower yields are a good thing, no one is going to argue because well, superficially this is true.  It’s an OK rule to live by.  But as is often said ‘nothing is absolute except death and taxes’.  There are even cases where yields can be too low, causing grapes to become overly concentrated and skins to get overly thick (increasing the tannin ratio) to the point where the resulting wine is too dense and out of balance.  Yes, that does happen, though not a lot.  But we’ll get to that another time perhaps.  No one needs to think about that on a summer Sunday morning...