Yield is one of the most cited data when speaking about quality wine. The obvious deduction is that the lower the yield is, the more concentrated the fruit will be, and so will the outcoming wine. AAWE (American Association of Wine Economists) has just pubished a chart with the average yield of the major wine producing countries. Germany is on the top with more then 9 tons / hectare, while Hungary has a moderate average yield / hectare with around 4 tons per hectare. Surprisingly enough Switzerland is rather on top even though its steep vineyards are hard to cultivate, and Spain, the biggest bulk wine exporter is much below the world average with 3.4 tons / hectares. The problem probably lies in the too big span examined by AAWE: Spain has invested a lot in irrigation system and other production increasing techniques recently. But the „mass productive Switzerland” is still a mystery. And low yield does not necessarily covers quality production, it can also be a result of aged, less productive vineyards. AAWE promised to share the whole database soon, which hopefully will turn the light on for us.
Meanwhile we suggest a clever writing by Richard Hemming MW, who has collected an immense amount of datum to make things clearer for us regarding the question of yield (including an example to show the yield of a grand cru burgundy):
Yield – lowest
Directly related to vine density is one of the most oft-cited pieces of data, yield. Normally expressed in hectolitres per hectare, where a hectolitre equals 100 litres, it gives a measurement of how much wine is produced from a given area. Again, there’s a presumption that vineyards yielding less wine should equate to higher quality, because restricting the volume of fruit being grown is supposed to result in greater concentration. The truth is more complicated, and requires some basic mathematics.
Yield is often enshrined in the appellation laws of traditional areas. One of the lowest is for grand cru burgundy, where a maximum yield of 35 hl/ha is specified for Le Musigny, for example. Importantly, vine density is also specified in these regulations, set at 10,000 vines/ha. With these two facts, we can start to put the figures in context.
Generally speaking, it takes between 130 and 160 kg of grapes to produce 100 litres of wine. For the sake of convenience, let’s say the average is 142 kg. So, 1.42 kg of grapes makes one litre of wine. Therefore, if one hectare of Le Musigny yields 3,500 litres, there must be around 5,000 kg of fruit (because 5,000 divided by 1.42 equals 3,500, near enough).
Hence why yield can also be expressed in tonnes per hectare – in this case, it would be 5 t/ha. Because we also know the planting density, we can calculate that each vine yields 0.5 kg of fruit, or approximately 0.35 litres of wine – so, roughly half a bottle per vine.
The lowest of all yields tend to be for nobly rotten sweet wine, whose grapes have shrivelled. In wine-trade folklore, Château d’Yquem produces only one glass of wine per vine. Can we prove this?
The average cited yield for Yquem is 9 hl/ha, which equals 1.2 t/ha of grapes. Planting density isn’t known, but its immediate neighbours have 7,000 vines/ha. That would give a yield per vine of 171 grams of fruit, which will produce around 0.12 litres of wine – very close to the standard small glass size of 125 ml. Rare indeed!
Yield – highest
At the other extreme, the Savatiano variety can yield up to 250 hl/ha – 27 times greater than that of Yquem! – and almost certainly at a lower planting density. Of course, with fertilisation and irrigation, yields can be forced ever higher, though such factory farming would inevitably result in dilute, poor-quality fruit from overworked vines. A respectable average seems to be between 40 and 60 hl/ha for quality wines. For much more detail on yields, see the Oxford Companion entry.
Yield – most expensive
Then of course, there is the consideration of the price of the grapes, measured either in US tons or metric tonnes. These two units are different (100 tons = 90.7 tonnes), but close enough to be able to make rough comparisons.
In 2015, the average price for a ton of red wine grapes in California was $783 [pdf], yet, as Alder reported, the price of Cabernet Sauvignon from the legendary To Kalon vineyard could be as much as $50,000 per ton. In South Australia, the overall average price was AU$631 per tonne [pdf], ranging from Colombard from the Riverland at AU$203 per tonne up to Eden Valley Cabernet Sauvignon at AU$2,358 per tonne. Meanwhile, Ferran recently wrote that 90% of Spanish grapes were sold for less than €500 per tonne.
|South Australia average||£361||€426||$475|
|Most Spanish grapes, less than||£423||€500||€557|
|Eden Valley Cabernet Sauvignon||£1,349||$1,591||$1,773|
|To Kalon Cabernet Sauvignon||£41,919||€49,462||$55,126|
I’ve converted these figures into GBP, EUR and USD per metric tonne in the below table to allow for a comparison.
Richard Hemming’s whole article can be read here