Wash and remove the seeds from the cherries. (A cherry pitter is a handy tool to use for this.) You should have about 10 cups of pitted cherries when you finish.

Dissolve the alum and the salt in 2 quarts of cold water. Add the cherries and allow to stand for 6 hours. (If the cherries tend to float, weight them down with a bowl.) Drain the cherries and rinse them with cold water.

In a separate large pan, combine the sugar and 2 cups of cold water. Bring to a boil and cook while you stir until the sugar is dissolved. Add the cherries, bring back to a boil and cook for 2 minutes. Remove from the heat. Add the red food coloring and almond extract and allow to stand in a cool place for 24 hours, stirring from time to time.

The next day, bring to cherries back to a boil and cook for an additional 2 minutes. Pour the boiling hot fruit into the prepared half-pint jars and process them for 5 minutes.

Store in a cool place.