Strawberry Balsamic Jam

Directions

1. 1
   ["Hull strawberries first; then wash and drain them.", "Mash them, in layers. (I pulse them in my food processor until they are the size I prefer... small chunks, but not totally pureed).", "Combine the strawberries, (or any kind of berry) with the sugar, pectin and balsamic vinegar and stir until blended.", "Bring to a continuous roll, stirring frequently, so it doesn't stick. Add a pat of butter to this, to prevent a lot of foaming. Otherwise, you have to skim the foam.", "Bring to a gel stage (approximately 10 minutes).", "To test if the fruit is at the gel stage, I like to chill a plate in my freezer. Spoon a little of the cooked fruit on the cold plate. Run your finger through it, and see if it separates. Let is sit a minute more and feel the texture. If it gels, it's ready.", "Pour into sterilized clean class jars with lids.", "Set the filled jars in a rack, covered by at least 2\" of boiling water. Keep the pot covered and set a timer for 10 minutes