Freezer jams are prepared without cooking. The consistency of the jam is not dependent on the cooking process. They are easy to make and use little equipment.
For best flavor, use fully ripe fruit. It is best to have the fruit at room temperature so the ingredients will dissolve more easily.
Follow the recipe exactly. Do not use more fruit or juice than the recipe requires.
Use one of the regular commercial pectins that include recipes for freezer jam. Follow the directions exactly and DO NOT REDUCE THE SUGAR.
Use 1–2 cup glass or rigid, plastic freezer containers with tight-fitting lids. Wash the containers in hot soapy water or run through the dishwasher. There is no need to sterilize containers or process jams.
Follow directions for preparation. In some recipes, the jam must be allowed to stand at room temperature for 24 hours; others can be frozen right after the jam is made. After opening the container, store in the refrigerator. Remember, the product is not cooked so it will ferment and mold quickly if left at room temperature for extended periods of time.
- Never substitute one pectin for another; they are not interchangeable and each is prepared in a different way.
- Do not reduce sugar. If sugar is reduced, the product will not set up. For reduced-sugar freezer jam, use one of the reduced-sugar products on the market.
- Do not double the recipes. Doubling recipes could result in a runny product, and it is hard to dissolve a large quantity of sugar. Sugar crystals could grow during storage, resulting in a grainy product.
- Corn syrup is added to some freezer jam recipes to help prevent sugar crystal formation.
- Measure accurately and follow directions exactly. The most common error resulting in failures is inaccurate measuring. Because freezer jam uses large quantities of sugar, it is a good idea to keep a record of each cup as it is measured. Be sure to use proper measuring equipment for dry and liquid ingredients.
- Leave at least a half-inch head space to allow for expansion of the product as it freezes.
Reduced-sugar freezer jams
There are commercial pectin products on the market that can be used to make reduced- or no-sugar freezer jam. Look for these products in the food preservation section on your market. Follow the manufacturer's directions for making these products.
Source: OSU Master Food Preserver Program