How Many Grapes in a Glass of Wine?

This morning at 530am, Harvest officially began in Napa with sparkling producer Mumm Napa starting us off yet again.

With the summer months beginning to wind down, kids are getting ready to start school, leaves will soon start to change, and significant others all over wine country are preparing to become “Harvest Widow(er)s” for a few months. With that in mind, let’s break down how many grapes/vines/acres it takes to put the sweet (or dry) nectar into your glass.

“How many grapes go into a glass of wine?” is a question I have heard asked over the years in tasting rooms, and on wine tours alike. The short answer is, it really depends on the producer. Many high production houses in the industry are trying to get as much wine as they can from each acre planted. While the small artisan style winemakers that are cultivating their vines to the point where they may get as little as 1 bottle of wine from a whole vine. Who is to say what is right? Some other variables you need to take into account are:

Varietal? – Some have small berries, some have large. Some are thick skinned (less juice), some have thin skins (more juice). 
Weather? – Rain can plump up the grapes. Sun can dehydrates them.
Press process? – Was it free run juice? Bladder Press???

What is a low yield? Some say that a winery that is only getting 2 tons of fruit per acre is low. My perspective has completely changed recently. During one of our staff tastings last week an Italian importer was showing off some wines that only got 2/3 of a bottle per vine. Edi Simcic Chardonnay (WSI 93+) and Podere Ciona Merlot (WSI 95) take so much care with their vines that they end up only getting about a half ton of fruit per acre. Compare that to Barefoot (EJ Gallo Company) Muscato that reportedly can get up to 15 tons per acre. Now those are low yields.

Below you will see a break down of a Medium to High yield vineyard.
1 grape cluster = 1 glass
75 grapes = 1 cluster
4 clusters = 1 bottle
40 clusters = 1 vine
1 vine = 10 bottles
1,200 clusters = 1 barrel
1 barrel = 60 gallons
60 gallons = 25 cases
30 vines = 1 barrel
400 vines = 1 acre*
1 acre = 5 tons
5 tons = 332 cases

We can also follow the grapes along their path from vines to bottles in the formulas below:
1 acre* = 5 tons of grapes = 400 vines = 16,000 clusters = 1,200,000 grapes
1 acre* = 5 tons of grapes = 13 barrels = 325 cases = 780 gallons = 3,900 bottles = 16,000 glasses

*An acre, as we know, is the amount of land tillable by one man and one ox in a day or the size of an American football field subtracting 10 yards and the end zones, i.e., a rectangle 90 yards long and 53 yards wide.