GRAPES 101

By kris Gerling

Grapes 101 is a series of brief articles highlighting the fundamentals the cool climate grape and wine production.

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How many grapes are in a party of wine? It's a question countless consumers ask as they gaze in ~ a vineyard exterior a winery. It's also a concern wineries ask together they inspection the tanks and shot to calculate production costs.

As with any kind of question the this nature, there are a many variables come consider. What type of grapes room we talking about? have actually they swelled up through rain or dehydrated since of sun or noble rot? just how were lock pressed? was it gentle, whole-cluster pressing or to be enzymes and also press-aids offered after crushing each and every berry? Therefore, the variability the products and also processes is component of the equation, and also the other part is switch factors.

What we can learn

Pounds of grapes in a party of wine

The number

150 gallons the wine every ton of grapes

Range

120-180 gallons in typical conditions

A standard bottle of alcohol is 750 milliliters (ml), definition a situation of 12 bottles includes 9 liters, or 2.378 gallons. In ~ 150 gallons per ton, a ton that grapes becomes 150/2.378 gallons per case, or a little an ext than 63 instances of wine. V 12 bottles every case, we have actually 756 party in total.

But how many grapes room we talking about? We have the right to go around this two ways. Through the numbers us have, we have the right to see that one bottle is around 1/756 or about 0.12% the a ton. 0.13% x 2000 pounds per ton is nearby to 2 and fifty percent (2.6) pounds the grapes every bottle. A grapevine might have 7 pounds that fruit (or more, or less), so through 2.6 pounds the fruit per bottle, one vine deserve to produce between two and also three party of dried wine.

1,600 grams of sugar can increase the volume of alcohol by one liter, for this reason if 2,000 (7,570 liters) gallons of dried wine is walking to it is in sweetened to 50 grams/ liter the residual street (5%), we're adding 50 x 7,570 = 378,500 grams of sugar. 378,500 split by 1,600 grams per liter amounts to 236.5 liters, or 62.5 gallons. This number could impress friend or it can not, yet the winery now virtually has the indistinguishable of 26 cases of alcohol (236.5/9 liters per case) to offer that is in reality sugar.

What we can learn

How countless grapes space in a party of wine

The number

0.2 pounds per cluster of grapes

Range

0.1-0.5 pounds every cluster

Conversely, we deserve to look at swarm weights the grape varieties and see that they variety from 0.2 pounds as much as a pound or more per cluster. For example, for Cabernet Franc, a most data indigenous the eastern joined States reflects cluster weights about 0.22 pounds/cluster. This means it would certainly take a little much more than 11 swarm (2.6 pounds/ 0.22 pounds per swarm = 11.8 clusters) to to fill one bottle. Actually, us won't incorporate the stems and seeds, which we'll speak to 15% the the swarm weight, therefore we have the right to bump it approximately 13 clusters.

If we use berry weights that 1.6 grams every berry, i m sorry is approximately the average we've viewed at harvest in the Veraison come Harvest newsletter the past couple of years, we can transform again: 28.3 grams/ounce divided by 1.6 g/berry equates to 17.7 berries every ounce. 2.6 pounds is around 41.6 ounces, and also when multiplied by 17.7 berries/ounce we arrive at 736 berries. Berry or clusters the are lot heavier or lighter would adjust the number significantly, that course. If a swarm of grapes has roughly 100 berries, we've acquired a little an ext than 7 clusters in the bottle, and also given all the variability in this counter one can get away with saying a swarm of grapes equals a glass of wine without being dubbed a liar.

What we have the right to learn

How to annoy a viticulturist

The number

4 lots of grapes per acre

Range

1-30 tons per acre

An acre, as we know, is the lot of soil tillable through one man and also one ox in a work or the dimension of an American football field subtracting 10 yards and also the finish zones, i.e., a rectangle 90 yards long and also 53 yards wide. The problem isn't the area, yet all the different things that have the right to be excellent within that area. Aside from the various grapes that deserve to be get an impression there, the vines have the right to be planted close together or far apart. The training mechanism will beat a big role in the yield, no to mention the floor characteristics and also climate. Depending on the particular acre, a yield of four tons per acre might be far too lot or far too little. In Europe, alcohol production figures are regularly reported together hectoliters every hectare. No of these figures is really familiar stateside, but a hectoliter (hl) is just 100 liters and a hectare (ha) is a soil measure tantamount to 10,000 square meters, or around 2.47 acres. A recent agricultural survey from the european Union provided a variety of 35 to 400 hl/ha. If we convert these number to tons/acre using 150 gallons per ton, we obtain a range of 2.5 to 28.5 tons/acre.

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So there you have actually it. We've travel from macro to micro come metric and also back. While ns think that many of the number I've supplied are reasonable, there are obviously many ways to come at really different answers. The is generally finest to track a offered wine native vineyard to bottle, and also when the data has been crunched for the wine, you have actually some precise information around that certain wine, period. Now you have actually some fast numbers you can run to form estimates, however. The gallon come liter switch won't change even as the tons per hectares, acres, oxgangs, and also furlongs totter wildly. If all of the conversions are acquiring out the hand, just remember the there was enough volume to to fill the present bottle, and also in the end isn't that all the really matters?

Chris Gerling is an enology extension associate in ~ Cornell's brand-new York State agricultural Experiment station in Geneva, NY.