I made the most beautiful grape jam this week. I followed a different recipe than last year, and I think this is a real winner.
The recipe I followed was at Chef in You found here: Grape Jam
During mid September I send my kids out every few days to bring me a big bowl of grapes. When I have 2 hours and The Office on Netflix, I make up a batch of jam.
Next, rinse, stem, and peel the grapes. It's not as bad as it sounds. Concord grapes are slipskin, meaning with a little squeeze they come right out of their jackets. But save the skins - you'll need them.
Bring the skinned grapes to a boil in a deep pan, and cook over medium heat for about 10-15 min till they break down and the seeds start to separate from the pulp. Strain out the seeds and return the juice and pulp to the pan. Bring up to med-high heat.
Add the skins in to the boiling grapes. I have done the skins in two ways. I have left them intact and I have pulsed them in the food processor first. I prefer pulsing them first but you can do it either way.
Cook for about 5 min and then add 3 cups of sugar. Cook and stir constantly till the jam thickens. It takes me about 20 min to get to the right stage. I use the spoon test and fridge test. From the Chef in You site, here's how to test for doneness: