How Many Grapes in a Bottle of Wine?

Today I received a question from a customer about how many grapes it takes to make one 750ml bottle of wine. (This will be good trivia to share with your friends!)

So, I asked our boutique wineries to help out with the answer.

It appears that generally 1.2 kg of grapes is required to make one 750ml bottle of wine (although this can vary depending on the winemaking technique - see below). And, I am told that 1.2kg of grapes is equivalent to 7 - 8 bunches of grapes.

There is one winery response in particular that you’ll find interesting:

        "Generally speaking 1kg in weight translates to around 1L (litre) of fluid. In the wine world it depends on the extraction rate achieved in the winery i.e. the volume that can be squeezed from the grapes in the press, and how you choose to make the wine.

        Our winery usually manages an extraction rate of around 70%. This means 1kg of our grapes results in approximately 700ml of juice i.e. almost a bottle of wine.

        Some people choose to make wine from free-run juice (juice that easily drains/runs off the crushed fruit in the press). And others choose not to press the grapes too hard - so do not achieve the same volume of juice from the same quantity of fruit.

        The fruit might also have been picked early (when bunches are full of juice) or late (withered or shrivelled and not juicy). Pressing the fruit extracts flavours and characters from the skins/seeds etc which you may or may not want.

        So the decision to press or not to press (and how to press) has a direct impact on the volume of wine you will achieve from your grapes. And that decision depends on the style of wine you're after, the fruit you're working with, and attitudes about winemaking techniques - another question altogether. "

This leads onto the next question, "how many grapes are there on a bunch?"

Well, this is what another winery has to say:

        "All varieties are different and regions will vary as to the bunch size and number of grapes on a bunch.

        Riesling from Clare Valley will have around 20 grapes to a bunch (weighing maybe 350g), but around 40 on a bunch of Shiraz (450g). Bunch weights will also vary from variety and region. It is very hard to determine the number of grapes only the weight of fruit."

So it seems like the number of grapes per bunch is also a large variable.