The grapes are easy to peel if you start from the opposite end of the stem (the side without a hole).
Color the grapes using the skins. Put the skins and water in a pan, and simmer for 5 to 10 minutes while mashing with a wooden spatula.
When it turns a bright red color as shown in the photo, strain and squeeze the liquid through paper towels or cotton gauze (or cheesecloth). Discard the skins, and return the simmering liquid to the pot.
Put the grapes and granulated sugar in the simmering liquid, and simmer to reduce for about 20 minutes. Skim off any scum.
Simmer until it reaches your desired consistency. We often have this with yogurt, so we like it rather liquidy.
The finished jam will be colored all the way through as shown. It will thicken when it's cool.
Transfer to sterilized jars to store.
Story Behind this Recipe
We received a lot of Kyohou grapes as a gift, so I turned some into jam.
When straining (squeezing) the jam at step 4, it's very hot so do it after cooling it down a bit. If you add some lemon juice at the end, the color will become very bright and pretty.