How much wine to make will depend on various factors including the number of guests, whether it’s a wine-drinking crowd, the format of the reception, the time of year, the time of day, and the menu. It is better to have a little more wine than not quite enough.
The standard 750ml wine bottle holds 25 ounces so count on five five ounce servings of wine from each bottle.
Follow these steps to estimate your needs:
Calculate how many people will be drinking at the event.
Multiply this number by four (to give you the maximum number of standard drinks per person you will need).
Divide number of standard drinks by five per bottle
Divide number of bottles by 30 to determine the number of batches and then round up
100 wine drinking guests attending
100 x 4 standard drinks = 400 standard drinks
400 / 5 (5 glasses per 750ml bottle) = 80 bottles of wine
80/30 750ml bottles per batch = 2.67 or 3 batches of wine will be needed
Therefore, you could make one batch of red wine, one batch of white wine, and one batch of rosé wine.