A simple recipe for making homemade grape juice requires mashing many pounds of grapes and then slowly simmering the grape mash for about 10 minutes. Afterwards, a thorough straining through a mesh sieve or cheesecloth will result in healthy, homemade grape juice.
The only ingredient needed to make grape juice is the grapes themselves, though two large pots and a mesh sieve or cheesecloth will also be required. Making grape juice requires a large amount of grapes, as a pound of grapes will only yield about a cup of juice.
After the grapes have been rinsed and destemmed, mash them in a large pot. This task will be easier with a potato masher or similar device. Simply Recipes recommends mashing at most four pounds of grapes at once, as more may prove difficult. Then slowly simmer the grapes in a large pot at a medium heat for about ten minutes, stirring and mashing occasionally.
After cooking, secure the mesh sieve or cheesecloth over another large pot and let the grape mash strain into the pot for several hours in a refrigerator. Finally, the juice can be poured from the pot into individual containers, and the leftover grape mash can be composted.