Blue grapes jelly

A huge plastic bag with fresh picked blue grapes arrived at my office desk early last morning. The commentary was: now you know what you will do tonight. These are surprises that I actually hate.
I had an appointment for an hour and I started to extract the juices a couple of minutes after I came home.

I use a steamer over hot water and that gets the job done. I weighted the bag and had 2,7 kilo in it. After an hour of steaming the grapes and crushing them with a potato masher I extracted 1,8 liter of dark red grape juice.

Then I went out to my appointment and came home a good hour later, allready planning what to do next. Most of the time I have enough clean mason jars sitting around so I can start making jellies. But the moment I checked,  just 6 large jars were available. I picked some small yogurt jars to fill in the overflow later and gave to my coworkers. They loved it.

2,7 kilo blue Portugeser grapes are about 1,8 l grape juice
750 g 3x1 jelly sugar with pectine
2 tsp citric acid

Mix the cold juice with the special sugar. Bring to a boil and let it cook rapidly for 6 min.  After 4 min add the citric acid.
Put a spoon ful of jelly on a cold surface. After a short time you should ge able to push a finger through and the line stays.
fill in clean jars, close the lid and set them on the lud for 5 min, then turn and let cool down.