Getting the Juice Out
You can certainly make good-tasting wine from jars of grape concentrate, but nothing compares to buying actual grapes and crushing them yourself. It is now possible to buy Vitis vinifera grapes in most states. If you live in New England, for example, you can buy California wine grapes from American Wine Grape Distributors, based in Massachusetts, which imports grapes such as Merlot and Chenin Blanc.
Before you can decide how many grapes to buy, you need to decide roughly how much wine you want to make. A very rough but helpful conversion is that one gallon of juice can be pressed from about 16 pounds of grapes. A half-ton of grapes will produce one barrel of wine.
Once you have your grapes, sort through them very carefully. If any grapes appear rotten or if any have slightly torn skins, remove them from the rest.
The U.S. government regulates home winemaking. While you no longer need a permit to make wine at home — this requirement was lifted in 1979 — it is still illegal for a household to produce more than 200 gallons (1,000 bottles) a year. It is also illegal to sell wine made at home, but this does not mean that you can't give bottles to friends.
Now comes the most tedious part. If you have bunches of grapes, you must separate the grapes from the stems by hand. Sure, you could buy or rent a destemmer, but they are more expensive than crushers and presses. If you crush the grapes with the stems attached, you risk adding needless astringency and bitterness to your wine. So, invite some friends over, open up some bottles of somebody else's wine, and have a destemming party.
If red wine is your goal, then the grapes go into the crusher. For home winemakers, crushers will fit very easily over your fermentation vessel, whether steel or plastic. If you wish to make a white wine from a white grape, you could put the grapes directly into the press and squeeze, thus bypassing the crushing process. The key for any white wine is to minimize skin contact. Presses are designed to channel the precious juice into a container waiting right next to it.
Even if you decide to crush white grapes before pressing, you must still press the must (skins, juice, seeds) before you start fermentation. When pressing white whole grapes or freshly crushed white must, it's a good idea to place some kind of sieve over the juice-receiving container, as this will trap seeds and other grape matter from mixing with the juice. You want the white grape juice to be as clear as possible.