homemade blueberry jam

When my sister-in-law and her 5 cute boys came to visit us over the weekend we went blueberry picking.  I had wanted to make blueberry jam (or any kind of jam) this summer but it seemed like a whole lot of work and I was dragging my feet so I was glad when my sister-in-law suggested we make jam together.  We busied ourselves in the kitchen and had a good time.

homemade blueberry jam (MCP, from the makers of Sure Jell Premium Fruit Pectin)
3 3/4 cups crushed berries
1 (1.75 ounce) box fruit pectin
6 cups sugar
1/4 cup fresh lemon juice
1 cup water

Crush fruit using a potato masher.  Measure exact amount of fruit into 6-or 8-quart saucepot.  Stir in lemon juice and water.   Stir in 1 box of pectin into fruit.  Bring mixture to full rolling boil (a boil that doesn't stop bubbling when stirred) on high heat, stirring constantly.  Stir in sugar quickly.  Return to full rolling boil and boil exactly 4 minutes, stirring constantly.  Remove from heat.  Skim off any foam with a metal spoon.  Ladle quickly in prepared jars, filling to within 1/8 inch of tops.  Wipe jar rims and threads.  Cover with lids.  Screw bands tightly.  Place jars in steamer.  Cover; bring water to gentle boil.  Process jams 10 minutes.  Remove jars and place upright on a towel to cool completely.  After jars cool, check seals by pressing middle of lid with finger.  If lid springs back, lid is not sealed and refrigeration is necessary.