Overview Jams and Jelly

Pectin thickened jams and jellies are the most common in the U.S.. Pectin gel strength is determined by the amount of pectin present, the amount of sugar present, and the amount of acid present. The fruit used contains some of each of these three gelling factors, but in unknown amounts depending on ripeness and growing conditions. This is why different batches will gel differently, and substituting the type of fruit in your favorite jam recipe may result in a different thickness. Commercial powdered pectins usually have an acid (such as fumeric acid) added to help gelling in case the fruit is very ripe and contains less acid than normal. Pectin manufacturers formulate their packaged products to vary slightly from other brands, so it is best to use a recipe for a specific brand of pectin.

Most jam and jelly failures are due to householder error, or creativeness. The boiling time must be monitored accurately. Start timing with the full boil stage (bubbles all over the surface in the saucepan), and use an accurate timer (one survey found 20% of household timers were inaccurate). Substituting honey for white sugar usually results in a softer gel, however many householders find they can substitute half this way and still have an acceptable gel. Jams and jellies contain a lot of sugar; they taste sweet. If you wish to prepare a lower sugar product, use a recipe specifically designed to require low sugar amounts. Simply decreasing the sugar in a standard recipe will result in a very weak gel.

To make low sugar jams and jellies, use a thickener other than pectin. Low Methoxyl Pectin (LMP), Carrageenen (Garden Fare brand), gums (Ball), and modified starches (Clear Jel) can thicken without sugar. The Low Methoxyl Pectins are common on grocery store shelves. Instead of sugar, they require calcium to form a gel. Many brands have calcium already added (MCP), but some (Pomona's Pectin) contain the calcium in a seperate packet. When using these alternative products, try a small batch first; sometimes the gel strength varies and you may need to alter the amount of fruit you add.

If your jelly or jam is too soft to use as a spread, and you do not wish to simply use it another way, it can be re-made. This involves starting completely over. Re-made jellies may still have an inferior consistency, but there is usually improvement. Re-making jams and jellies is time consuming and requires more pectin, however for expensive recipes it may be a practical alternative.