Recipe 08.04.16: Canning Jam

Combine equal weights of fruit puree and sugar in a large heavy pot, one that allows several inches of headroom between the mixture and the top of the pot.

Cook the mixture over medium-high heat until the sugar is dissolved.

Bring the mixture to a rolling boil. Let it remain at a rolling boil for five minutes undisturbed. Keep an eye on the mixture to make sure it does not boil over. If it seems like it might do so, stir it down and then decrease the heat so it does not.

After the mixture has boiled for a full five minutes, turn off the heat and skim off any foam.

Carefully ladle the hot jam mixture into clean, sanitized jam jars. Screw the lids firmly onto the jars and invert them. After ten minutes, turn the jars right-side up. Let the jam cool, then refrigerate. 

Refrigerated, this jam will keep for up to one year. Should you wish to can your jams using the boiling-water method, which will preserve them for several years unrefrigerated, you can find guidelines for doing so on the National Center for Home Food Preservation website, or, alternately, in the classic textbook on home canning, “Putting Food By” (New York: Plume, 2010).