Jams and Jellies: Problems and Solutions (SP 50-746)

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Problem Cause Prevention
Formation of sugar crystals Excess sugar
Undissolved sugar sticking to sides of kettle
Mixture cooked too slowly or too long
Mixture cooked too little
Follow recipe exactly.
Wipe side of pan free of crystals with damp cloth before filling jars.
Cook at a rapid boil.
Remove from heat immediately when jellying point is reached.
Cook until sugar has completely dissolved and mixed with fruit juice.
Products are safe to eat.
Syneresis or "weeping" Excess acid in juice makes pectin unstable
Storage place too warm or storage temperature fluctuated
Product was sealed with paraffin
Maintain proper acidity of juice.
Store in a cool, dark, dry place.
Seal with lids and process.
"Weepy" products are safe to eat.
Too soft Overcooking fruits to extract juice
Incorrect proportions of sugar and juice
Undercooking causing insufficient concentration
Insufficient acid
Making too large a batch at one time
Avoid overcooking as this lowers the jellying capacity of pectin.
Follow recommended instructions.
Cook rapidly to jellying point.
Avoid using fruit that is overripe.
Add lemon juice if needed.
Use only 4 to 6 cups of juice in each batch of jelly.
Products are safe to eat.
Too stiff or tough Overcooking
Too much pectin in fruit
Cook jelly mixture to a temperature 8 degrees higher than the boiling point of water for jelly.
Use ripe fruit.
Products are safe to eat.
Cloudy Fruit was green
Imperfect straining
Jelly allowed to stand before it was poured into jars and poured too slowly
If product does not have airtight seal, may denote spoilage. If there are moving bubbles, do not use
Use firm, ripe fruit, or slightly under ripe.
Do not squeeze juice; let it drip through jelly bag.
Hold kettle close to top of jar and pour jelly quickly into jar.
Follow recommended methods to get airtight seal.
Cloudy products are safe to eat unless there are moving bubbles or product appears spoiled.
Mold (denotes spoilage; do not use) Imperfect seal
Paraffin seal not airtight, reusing paraffin
Lack of sanitation
Too little sugar
Seal with lids and process in boiling water bath.
Do not use paraffin, use 2-piece lids and process in boiling water bath.
Sterilize jars if processing time is less than 10 minutes.
Following processing recommendations for low-sugar jellied products.
Moldy jams and jellies are not safe to eat and should be discarded.
Fading Storage place too warm or too light
Storage too long
Store in cool, dark, dry place 35-50 degree F.
Use oldest products first.
Products are safe to eat.
Fruit floats in jam Under ripe fruit
Not thoroughly crushed
Undercooking
Improper packing in jars
Use ripe fruit.
Crush fruit uniformly.
Cook rapidly following instructions.
Products are safe to eat.
Bubbles Kettle was not held close to top of jar as jelly was poured, or jelly was poured slowly and air became trapped in hot jelly.
If product does not have an airtight seal may denote spoilage. If bubbles are moving, do not use.
Hold kettle close to top of jar and pour jelly quickly into jar.
Follow recommended methods to get airtight seal.
Jellied foods with bubbles safe to eat unless there are moving bubbles or product is spoiled.
Crystals in grape jelly Tartrate crystals. Formed from the tartaric acid naturally present in grapes. To minimize crystal formation, let the freshly extracted grape juice stand in the refrigerator two to five days. Pour or decant and strain the clear juice again through a jelly bag or coffee filter before making the jelly
Dark surface Air in jar. Indicates the jar of jelly was sealed with too much air, or the seal failed.
Darker than normal coloring Overcooking sugar and juice. Recipes with added pectins are cooked less and result in better and brighter color.
Wine-like flavor or odor Inadequate heat processing or stored too long in the refrigerator. Caused by yeast fermentation of the sugar to alcohol and carbon dioxide. If there is no mold on or in the jelly, it is safe to eat.

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Source: Food Safety Advisor Volunteer Handbook Washington State University/University of Idaho, 2002

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