Here is a pair of standard size scissors next to some of the grapes. They were really tiny grapes and most of the fruit was filled with a seed.
I collected a plastic grocery bag almost full of grapes still on their stems. Once they were cleaned and rinsed they looked like this.
First I froze the grapes overnight. That is a trick I learned a long time ago by accident. It helps the fruit to release more juice.
I followed it pretty exactly although I ended up with 4 1/4 cups of juice. I used 3 cups of juice to make the jelly and ended up with 6 jars of beautiful purple jelly!