When canning jam, combine fresh fruits with sugar and boil them slowly until the sugar dissolves. Boil the mixture rapidly once the sugar dissolves until the jam gels, then add 1-2 tablespoons of lemon juice. Ladle the hot jam into hot jars and process them in a water bath canner, adjusting the processing time per elevation.
Is it Better to Water Bath Can or Pressure Can Jam?
Jams should be preserved using a boiling water bath canner. Most fruits for making jam are high in acid or easy to acidify with lemon juice, which makes jam safe for water bath canning. Furthermore, pressure canning exposes the jam to higher temperatures that may cause it to lose flavor, color, and texture.Print
Tips for Canning Jam
Making jam is an art you master with repeated practice, and getting it right each time may be tricky. It’s easier to get excellent results when canning jams by following scientifically approved guidelines for canned food safety.
Follow these tips to make canned jam better:
- Add ½ teaspoon of butter or margarine to the fruit juice mixture to reduce foaming. This is optional and may corrupt the flavor of the jam in excess.
- Avoid doubling the recipe because this causes flavor loss, poor gelling, or producing darkened jam.
- Boil the jam mixture rapidly after the sugar dissolves since slow cooking ruins the added pectin or natural pectin in the fruit juice.
- Ensure your jam reaches safe canning temperatures of 220-222°F to kill botulism-causing bacteria and make it shelf stable.
- If using frozen fruits to make jam, defrost the frozen fruit first.
- Use a non-reactive pot for boiling jam, as the acid may react with the pot and alter the flavor of the jam.
- Use a wide pot when cooking jam fruits to increase the surface area for moisture loss through evaporation.
Can You Can Jam Without Sugar?
Jams and jellies are usually made with granulated white sugar. The sugar helps with gelling and flavor while acting as a preserving agent. The rule of thumb is to use ¾ cup of sugar for every fruit cup.
The National Center for Home Food Preservation warns against canning sugar-free jams or versions with reduced sugar using untested recipes. It recommends using modified industrial pectins to reduce or eliminate sugar.
If you want to do away with added sugar, use other jam-sweetening alternatives like corn syrup or honey. Use half the amount of corn syrup to replace the sugar amount the recipe requires. When replacing sugar with honey, use light honey and add half of it for the sugar amount the recipe requires since honey has more calories than sugar.
The downside to using honey or corn syrup is the risk of masking the fruit flavor of the jam, especially if they are used in excess. Using alternatives may also cause poor gelling. Additionally, jams with no added sugar are better refrigerated or frozen than canned.
Should Pectin Be Used When Canning Fruit Jam?
Pectin is only necessary when canning fruit jam that is made with low-pectin fruits. It’s also required for low-pectin vegetables.
The following low-pectin fruits and vegetables require added pectin for successful gelling:
- Berries: Blackberries, blueberries, boysenberries, red raspberries, strawberries, and gooseberries.
- Fruits: Grapes, cherries, peaches, plums, figs, and pears.
- Vegetables: Rhubarb and tomatoes.
Is Lemon Juice Required for Canning Jam?
Lemon juice is required for canning jams if the fruits are low in acid and natural pectin. Using fully ripe fruits only or a poor balance of fully ripe and slightly underripe jam fruits necessitates using lemon juice.
While you can use bottled lemon juice, freshly squeezed lemon juice is better. Add 1-2 tablespoons of fresh lemon juice for a standard batch of two cups of fruit. Besides acidifying the jam for safe water bath canning, lemon juice also adds natural pectin for successful gelling. This eliminates the need for commercial pectin.
The following low-acid fruits require lemon juice for good thickening or gelling:
- Berries: Boysenberries, blackberries, gooseberries, strawberries, dewberries, and raspberries.
- Fruits: Apricots, peaches.
What Equipment is Needed for Canning Jam?
You’ll need the following kitchen items and canning supplies to can homemade jam:
- Canning tongs or jar lifter
- Food mill or sieve for jams made from fruits with seeds for seedless jam
- Jelly or candy thermometer
- Large non-reactive stockpot or pan for cooking jam
- Paper towels
- Potato masher or immersion blender
- Straight-sided canning jars with new lids and clean rings
- Water bath canner with a rack
- Wide-mouth canning funnel
Can I Use Frozen Fruit to Make Jam?
Yes – you can use frozen fruit to make jam. The trick is to thaw the fruits first to bring them to room temperature to reduce the cooking time for the jam.
How Long Do You Boil Jam for Canning?
The boiling time for jam ranges between 30 and 40 minutes, depending on the type of fruit and whether or not the jam features added pectin. Soft fruits like berries cook faster. Jam recipes with no pectin require longer cooking time to gel successfully.
To check the doneness of cooked jam, use a thermometer. The jam should be 220°F at sea level and 2°F less for every extra 1,000 feet gained in elevation, but not less than 212°F at any elevation.
Best Way to Store Canned Jam
The best way to store canned jam is to keep sealed jars at room temperature in a cool, dry, dark place. Avoid heat, direct sunlight, light, dampness, and extreme temperature fluctuations in the storage area.
Do You Need to Refrigerate Canned Jam?
No – properly sealed canned jam is shelf stable and can be stored safely at room temperature.
What is the Shelf Life of Canned Jam?
According to the USDA, successfully sealed canned jam has a shelf life of one year. It’s best to use the jam within six months for the best flavor and texture.