I let it steep for a while, sieved it and added sugar. For 1 liter (about 1 quart) I added a bit less than 1 kilo (about a pound) of sugar.
I used a candy thermometer and boiled it to 104°C / 217°F and then poured it into canning jars. Let it cool. Close the lid and store in the fridge.
It turned out delicious.
Amazing how we always tend to think of everything as single use. Now I have my traditional Red Currant jelly, a traditional Black Currant Jelly and this great new experiment that I got for not a lot of trouble and leftover used berries that were on their way to the compost heap.