Jams, Jellies, and Aspics

  Jams, jellies, and similar things tend to preserve food longer for a couple reasons. One is sterile initial packaging, although this tends to be over once one opens the jar.

  The other, much larger reason is reduced water content.



  There are many gelling agents used in making jams, jellies, aspics, marmalades, preserves, comfitures, and the like. The two most common, however, are pectin and sugar, and the last is a powerful drying agent and will help with preservation thusly. Agar, from the macroalgae seaweeds in the Gigartina, Eucheuma, or Gracilaria genus, and gelatin, from the denaturization of collagen in meats, are also used; the latter is not vegan or vegetarian.

  Jellies, in their various forms, need not be sweet, though preserved fruits often are. Aspic, for instance, is a meat jelly made from gelatin, and a similar product was used to create "instant soup disks" by boiling a soup made with tough cuts of meat (i.e., high-collagen) until a small amount of liquid was left, cooling the jelly, and drying it to a hard disk. Most non-sweet fruits such as cucumber or tomato, if jellied, are also made as a savory jelly.




  Most fruit contains a fair amount of pectin, and the simplest way to make a jam or jelly is to dump a bit of syrup or sugar on fruits and boil them in a pot or pan - usually depending on how much one is making - until they form a jelly in their own juice. Raspberries are known for being especially high in pectin. The white part of the citrus peel is rich in pectin, but imparts a bitter flavor, and simply slicing a citrus fruit into thin slices with the peel on, and boiling it with a little bit of water and sugar overnight and stuffing it all in a jar is called marmalade.

  Then there is pomace.

  Apples contain an astounding amount of pectin, and if you squeeze apple flesh for its juice, and rinse it with water to get any remaining juice out, the flavorless white pulp is called pomace. It has a huge pectin content, lacking the bitter flavor of the white flesh of the citrus peel Should you find a fruit which lacks the natural pectin to be a jelly or jam (which is rare), just boil a little pomace in the water used to make the minimal amount of syrup to cover it, and enjoy.

  While sterile canning measures are best for long-term storage, jams, jellies, and preserves keep for longer periodsentirely because their water content is low. Once the lid is unscrewed once, that (and sugar being a further drying agent) is the only thing preventing spoilage, though some add a small amount of vinegar or citric acid near the end as a further preservative, at the cost of some flavor.




  If you're wondering if the jelly and jam making method can be summarized as "just smoosh fruit, maybe add some sugar to its juices, and cook it down," the answer is "yes." While there is more you can do, that is exactly what is happening.


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