5 cups fresh, ripe blueberries (4 pints or so)
2 tablespoons lemon juice
5 cups sugar
2 packages liquid fruit pectin (they come 2 per box)
3 teaspoons vodka
Using a food mill, crush about half of the blueberries, keeping the remaining intact into a 6-8 quart sauce pot. Add lemon juice. Add in sugar. Place over high heat and stir until mixture comes to full boil. Cook gently 3 minutes. Add in the fruit pectin and boil for exactly 1 minute more. Remove from heat, skim off foam with metal spoon, ladle into jars to 1/8 inch top of jars. Cover with a clean dish towel and let cool completely.
Drizzle 1/2 teaspoon of vodka into each jar and swirl to cover the surface layer of jam. Seal tightly and make pretty with a bow or jam cover cloth.