What are the specifics of commercial jam production?
Jams and jellies are made from fruits, berries and some vegetables. Some produce, like pears and raspberries, are best jammed and jellied if picked slightly underripe, whereas ones like plums and cherries are best when just ripe. The combination of ingredients for commercial jams and jellies is 1% pectin, 65% sugar, and an acid concentration of pH 3.1, which is most often attained by adding citric acid.
The commercial process for manufacturing jams and jellies comprises seven steps, which includes packing and shipping. The one difference between jams and jellies is that, for clear jellies, pulp, seeds, and skin are removed from the fruit mixture at the cleaning/crushing phase and after the pasteurization process.
Step 1: The fruit is inspected for selection, cleaned and crushed.
Step 2: The fruit is cleaned, including pitting, peeling and coring, and crushed and a paddle pushes the crushed fruit along; for jam, everything is paddled along, whereas for jelly, just the juice is paddled along.
Step 3: The preparation is moved through pipes to large vats. It is cooked according to a precise method to produce pasteurization. It is heated to below the boiling point (212° F [100° C]) then immediately chilled to below freezing (32° F [0° C]). Afterward, jelly preparation will be filtered for pulp, skin, and seeds.
Step 4: After an optional dejuicing, the mixture is piped to large refrigeration tanks to await further cooking.
Step 5: Separate amounts are then cooked in large kettles, then cooled, usually for three cooking/cooling cycles. Any optional ingredients are added at this time.
Step 6: Pre-measured amounts of the finished jam and jelly mixtures are poured into sterilized jars on a conveyor belt and metal caps are vacuum sealed atop them, thus insuring the sterility of the jams and jellies.
Step 7: The jars are then labeled with FDA approved labels and packed for shipping.