Frequently Asked Jam and Jelly Questions

Why should cooked jelly be made in small batches?
Should jelly be boiled slowly or rapidly?
What do I do if there's mold on my jellied fruit product?
Why did my jellied fruit product ferment, and what do I do?
What happens if my jam or jelly doesn't gel?
Can I add Epsom Salt to my jelly or jam to make it gel?
How long can I keep my homemade jams and jellies on the shelf?
How long can I keep my homemade jams and jellies once I open them?

Why should cooked jelly be made in small batches?
If a larger quantity of juice is used, it will be necessary to boil it longer thus causing loss of flavor, darkening of jelly, and toughening of jelly.

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Should jelly be boiled slowly or rapidly?
It should be boiled rapidly since long, slow boiling destroys the pectin in the fruit juice.

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What do I do if there's mold on my jellied fruit product?
Discard jams and jellies with mold on them. The mold could be producing a mycotoxin (poisonous substance that can make you sick). USDA and microbiologists recommend against scooping out the mold and using the remaining jam or jelly.

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Why did my jellied fruit product ferment, and what do I do?
Jellied fruit products may ferment because of yeast growth. This can occur if the product is improperly processed and sealed, or if the sugar content is low. Fermented fruit products have a disagreeable taste. Discard them.

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What happens if my jam or jelly doesn't gel?
Remaking cooked runny jam or jelly instructions can be found on our website at http://www.uga.edu/nchfp/how/can_07/remake_soft_jelly.html. Remaking uncooked jams or jellies can be found in a Oregon State University factsheet at http://extension.oregonstate.edu/fch/sites/default/files/documents/sp_50-604_remaking_soft_jellies_2009.pdf .

Can I add Epsom Salt to my jelly or jam to make it gel?
Several old jam or jelly recipes called for Epsom Salt to help the product gel, but this is NOT a recommended practice.

Epsom Salt is a bitter, colorless or white crystalline salt which is a hydrated magnesium sulfate. Magnesium has the ability to form weak links with pectin in the presence of sugar and acid. Epsom Salt was thus used in an old method for testing for natural pectin content in fruit juice before making jelly, as it does cause pectin to gel when magnesium ions are released in solution.

Epsom salt (magnesium sulfate) is a cathartic (laxative), regulated by FDA as a medication or drug, not as a food ingredient. Possible side effects or hazards from ingestion of Epsom Salt include nausea, vomiting, abdominal cramps and diarrhea. Whereas there are some food grade forms of liquid magnesium sulfate used in approved food manufacturing situations, the dry (anhydrous) Epsom Salt found in drugstores is usually labeled: may be harmful if swallowed and not intended for ingestion.

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How long can I keep my homemade jams and jellies on the shelf?
For best quality, it is recommended that all home-canned foods be used within a year. Most homemade jams and jellies that use a tested recipe, and have been processed in a canner for the recommended time, should retain best quality and flavor for up to that one year recommended time. All home-canned foods should be stored in a cool, dark, dry place, between 50-70°F. Over extended periods of time, however, changes in color, flavor, texture and nutrient content of home-canned jams and jellies is inevitable. A typical full-sugar fruit jam or jelly should be safe to eat if the jar seal remains intact and the product shows no visible signs of spoilage from molds or yeasts.

Additional reading about processing jams and jellies and storing home-canned foods:
http://www.uga.edu/nchfp/how/general/storing_canned_foods.html
http://www.uga.edu/nchfp/how/general/how_canning_preserves_foods.html
http://www.uga.edu/nchfp/publications/uga/uga_processing_j_j.pdf

Some jams and jellies may have a shorter shelf life than others for optimum quality. For example, lighter-colored jams and jellies may noticeably darken faster than others and not remain appealing for a whole year. Though this is not a safety concern, it may reduce the visual appeal of the product for many people. The type of fruit used will also affect other quality characteristics over time.

Reduced sugar jams and jellies may deteriorate in color and texture more quickly as they lack the full preservative effects of the sugar. Some fruits may darken more quickly with less sugar present. Flavor changes that occur over time become more evident if they are usually otherwise masked by the sugar.

Freezer/refrigerator jams and jellies are a distinct category of products that have to be stored in the refrigerator (usually up to 3 weeks) or frozen for up to a year.

It is always a good practice to carefully examine all home-canned jars of food for signs of spoilage prior to opening and eating. If there is any mold on a jar of jam or jelly, or signs of other spoilage, discard the entire contents of the jar or container. Follow the links below for additional reading on testing jar seals when you first process jams and jellies and then identifying spoiled foods in storage:
http://www.uga.edu/nchfp/how/general/cooling_jars_test_seals.html
http://www.uga.edu/nchfp/how/general/identify_handle_spoiled_canned_food.html

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How long can I keep my homemade jams and jellies once I open them?
Opened home-canned jams and jellies should be kept in the refrigerator at 40°F or lower. “Regular” – or pectin-added, full-sugar – cooked jams and jellies are best stored for 1 month in the refrigerator after opening. They may last longer depending on the specific product and how it is used. The expected shelf life will be shortened by keeping the container frequently open and/or out at room temperature for long periods of time during use. At each use, you can spoon out the quantity of jam or jelly that you may require into a bowl, and replace the jar in the refrigerator quickly - this would ensure minimum exposure to sources of microbial contamination during use. Do examine the container regularly during storage for any signs of spoilage like molds, yeasts and off odors (including a fermented, “yeasty’,” or “alcohol” odor), once it is opened. Discard the entire contents of the container if these are detected.

Lower-sugar or no-sugar-added spreads may have a shorter refrigerated shelf life than those made with the traditional amounts of sugar. Natural flavor changes in the fruit base are more noticeable without the sugar to mask them; for example, some lower-sugar spreads may taste more tart or acidic over time. Light-colored spreads may also darken more quickly with less added sugar.

Freezer jams also have to be stored in the refrigerator after thawing and will only retain good quality for 3 to 4 weeks after opening. They are subject to more syneresis (“weeping” or separation of liquid from the gel) than cooked jams and jellies.

Note: For safe eating practices, store your opened jar of jam or jelly in the refrigerator until consumed, and examine it frequently for signs of spoilage (like mold or yeast growth, or off-odors, including “fermented,” “alcohol” or “yeasty” odors). Discard the product immediately if any signs of spoilage are detected.

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