How many grapes are in a bottle of wine?

About 1.2 kilos of grapes yields a bottle of 0.75 litres, calculated using the pressing yield laid down by law in Champagne.

The product specification of the appellation allows 102 litres of cleaned must per 160 kilos of processed grapes. Those 102 litres fill 136 bottles of 0.75 litre, and 160 divided by 136 comes to 1.18 kilos per bottle.

Outside Champagne the press yield differs and varies per appellation and per wine house. The order of magnitude of a little over a kilo per bottle remains usable.

Grape berries differ greatly in weight, and that weight determines how many berries fit into the same 1.2 kilos.

In a study in the journal Horticulturae, bunches of four varieties were weighed and counted. Bunch weights ranged from 72 to 434 grams, with roughly 155 to 170 berries per bunch. Per berry that works out at roughly half a gram to well over two and a half grams.

Convert that to 1.2 kilos and you get about 450 berries for large grapes and close to 2,500 for very small ones. A berry of 1.5 grams, roughly the midpoint, gives about 780 grapes per bottle.

In Champagne, a hectare may yield a maximum of 12,400 kilograms of grapes, good for about 10,500 bottles of 0.75 litres.

At the maximum yield of 15,500 kilos per hectare this rises to about 13,100 bottles. Both limits are in the product file of the appellation.

Appellations with a lower permitted yield produce fewer bottles per hectare. Old vines and strict yield rules therefore literally mean more grapes behind every bottle.

The 0.75 litre bottle is one of the nominal quantities that European regulations lay down for pre-packaged wine.

Besides 0.75 litre, that regulation names, among others, 0.1 litre, 0.25 litre, 0.375 litre, 0.5 litre, 1 litre and 1.5 litres. Other sizes are not permitted for wine in trade.

Because the size is fixed, the number of grapes per bottle is a meaningful question: 0.75 litres means the same volume everywhere.

A magnum of 1.5 litres contains twice as much wine as a standard bottle and therefore takes about 2.4 kilos of grapes.

With a berry of 1.5 grams that comes to about 1,560 grapes. A half bottle of 0.375 litres, on the other hand, requires about 0.6 kilos, or about 390 berries.

The ratio stays directly proportional to the volume, because the pressing yield per kilo of grapes is the same regardless of bottle size.