Remove the seeds and skin from the grapes. Put the skin in a dashi stock bag. Refer to this recipe for an easy way to remove skin and seeds. (Recipe ID: 1563738)
In a pan, place the dashi stock bag with skin at the bottom and add grapes and other ingredients on top. Heat over medium-high heat.
When the corner stats to simmer, bring down to medium-low heat and simmer. Skim off the scum.
When the sauce turns to deep red purple, take out the dashi stock bag with skin and continue simmering.
When the sauce thickens, turn down the heat to low. Take a small amount of sauce in a cold metal spoon and check the thickness when it's cooled.
I baked it with almond cream tart (Recipe ID: 1565795).
Story Behind this Recipe
I received a bunch of Kyoho grapes for free.
The amount of sugar is 10 g to every 100 g of grapes with skin and seeds (in a 1:10 ratio), so adjust it according to the amount of grapes you use. Grapes will fall apart if you don't treat them gently, so be careful not to stir too much.