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Jam not Setting - How to Get All Jam to Set

Updated on November 15, 2016
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John applies his scientific & research skills (PhD) to develop recipes, food guides, reviews of healthy whole foods, ingredients & cooking

It happens over and over again. You decide to make some jam. You peel the fruit, you boil it, stir it, poke and prod it, but it won't set. You follow the recipe with meticulous care and attention to every minute detail and the jam still won't set. Why, Oh Why, does this happen?

What can you do to guarantee that the lovely jam, that you spent hour and hours, making over a hot stove, will set every time?

You may have seen lovely rows of luscious ripe strawberries on sale cheaply in the supermarket. You decide to make some strawberry jam, but it won't set no matter what you try.

What could be wrong? Discover why strawberries are a nightmare for jam makers?

Discover which additives work if you get desperate with that pot of liquid that won't gel.

Don't worry and fret anymore as this article provides all the answers for how to get all jams to set properly every time.

Homemade Fig and Raspberry Jam. Yup!
Homemade Fig and Raspberry Jam. Yup! | Source
Homemade jam is delicious and easy to make if you know how. Find out how to get it to set properly every time!
Homemade jam is delicious and easy to make if you know how. Find out how to get it to set properly every time! | Source
Scones and homemade strawberry jam - simply delicious
Scones and homemade strawberry jam - simply delicious | Source
Fabulous homemade jam - set very nicely
Fabulous homemade jam - set very nicely | Source

What Makes Jam Set? What can go Wrong?

The answer is pectin, which is a naturally occurring sugar-like substance (a polyscaccaride) found in berries, apples and most other fruit.

When heated with sugar, provided the acidity is correct pectin causes the liquid to thicken in a similar way to how gelatin makes a jelly set.

So what is needed for the pectin reaction to occur and for the fruit liquid to become a gel?

What can go wrong?

  • Many fruits contain too little pectin. You guessed it - Strawberries
  • Many fruits contain insufficient pectin and so are very prone to slight changes in acidity or sugar levels affecting the gelling process.
  • The amount of pectin in fruit declines as the fruit ripens
  • The correct amount of acidity is crucial for the to gel process to work. If the liquid is too acidic the gel will never set. If it is too acidic, the gel will lose liquid (weep) and become clumpy and watery. For fruits naturally low in acidity, or unripe fruit, the trick is to add lemon juice or some other fruit as a 'helper'. Kiwi fruit is ideal as it is acidity and rich in pectin.
  • The amount of sugar is also critical. Sugar also acts as a preserving agent and contributes flavor. Many people make the mistake of omitting the sugar from the recipe for health reasons. But this does not work as the jam won't set and it is likely to be more prone to bacterial and other infections ruining the jam.

The bottom line is that many jams will need added pectin to set.

This especially applies to strawberries which have little or no pectin, particularly when ripe.

To get strawberry jam to set you will need to add pectin and perhaps lemon juice.

Or you can add some kiwi fruit.

Amount of Pectin Naturally Occurring in Fruit

The table below provides a lists of three groups of fruits with different amount of pectin. The solution is to add extra pectin for fruits that are deficient.

  • Fruit which has adequate pectin to gel
  • Fruit which is marginal and may require pectin if the fruit is ripe
  • Fruit that will always require pectin.

Fruits that Do and Don't Require Pectin and Acid for Jams to Set

Always requires added Acid or Pectin, or both
Low in Pectin or Acid, need to add either or both
Unripe fruit has sufficient natural Pectin and Acid (add some sugar)
Apples, ripe
Apples, sour
Blackberries, ripe
Blackberries, sour
Cherries, sweet
Cherries, sour
Grapes (Western Concord)
Grape Juice, bottled
Grapes (Eastern Concord)
Grapes (California)
Plums (Italian)
Plums (not Italian)
Citrus with skins ( grapefruit, lemons, oranges, tangerines, limes, etc. - the pectin is high in the skin but low in the fruit)

Making Jams with Reduced Sugar or Sugar Substitutes

Generally the safest way is to add pectin or gelatine to ensure the jam will set. Always follow a recipe that is designed for a low-cal jam.

Making Jam with No Added Pectin

Wash all fruit and rinse thoroughly before cooking, but do not soak the fruit. For best flavor, use half-ripe fruit, not unripe and starchy, but not fully ripe and soft. Very ripe fruit has less pectin and acid. Remove the skins (optional for some fruits) stems, and pits from fruit, then cut into pieces and crush. Measure the amount specified below or in the recipe using the crushed fruit, not the fresh fruit. Place it into a large saucepan and add the ingredients shown below (of follow a recipe). Add the sugar and quickly bring the fruit to a boil while stirring strongly and continuously. Keep boiling until mixture starts to thicken.

Testing When Jams Will Set When Cooled.

Temperature test: Use a standard candy thermometer and heat until mixture gets to temperature specified for your altitude:

  • Sea Level 220 degrees F (104 degrees C)
  • 3,000ft 216 degrees F (102 degrees C);
  • 8,000ft 205 degrees F (96 degrees C)

Refrigerator test: Take a tablespoon of jam, put it onto a small plat that has been chilled in the freezer. Out it back into the freezer for a few minutes. If the sample gels, the jam is ready to bottle.

Remember that jam may take several days to gel properly in the bottles.

Making Jams and Jellies with Added Pectin

Jam made from fresh fruits, frozen fruit or canned fruit of all types can guaranteed to set by adding powdered or liquid pectins. The two types of pectins require different methods. Jams made with added pectin have larger yields and require less cooking and time for the liquid to reduce. Such jams have more natural fruit flavours for these reasons. Generally follow the recipes below as a guide, and follow the amounts of pectin specified on the pectin packages. Adding about 1/2 teaspoon of margarine or butter helps reduce foaming. However, these may cause off-flavor in a long-term storage of jellies and jams. Fruits for which added pectin works are spiced tomato, strawberry, rhubarb, plum, pear, peach, orange marmalade, grape, gooseberry, fig, currant, cherry, blueberry, youngberry, red raspberry, loganberry, dewberry, boysenberry, blackberry and apricot.

Sample Recipes - Note: Always follow a recipe designed specifically for each type of fruit

Blackberry Jam made with liquid pectin

  • 4 cups crushed blackberries
  • 1 pouch liquid pectin
  • 7 cups sugar

Measure crushed blackberries into a pot. Add the mixture sugar and combine well. Uisng high heat and stirring continuously bring the mixture to the boil quickly and boil vigorously for 1-3 minutes. Remove from the head and stir in the pectin. Skim to remove any skum taht has formed. Pour the jot liquid immediately into hot, sterile jars, leaving a small amount of headspace and seal/

Blackberry Jam made with powdered pectin

  • 4 cups crushed blackberries (about 3 quart boxes berries)
  • 1 package powdered pectin
  • 8 1/2 cups sugar

Follow the same procedure as above

Apricot Jam without added pectin

  • 8 cups crushed, peeled apricots
  • 1/2 cup lemon juice
  • 6 cups sugar

Plum Jam made without added pectin

  • 8 cups chopped tart plums (about 4 pounds)
  • 6 cups sugar
  • 1 1/2 cup water
  • 1/4 cup lemon juice

Plum Jam made with liquid pectin

  • 4 1/2 cups crushed plums
  • 7 1/2 cups sugar

Guide to Jam Making Problems and Their Remedies

The table below summarizes the various problems that often occur when making jam and some suggested remedies

Remedy of Prevention
Formation of crystals
Excess sugar.
Use a tested recipe and measure ingredients precisely
Formation of crystals
Undissolved sugar sticking to sides of saucepot.
Dissolve all sugar as jelly cooks. If necessary, wipe side of pan free of crystals with damp cloth before filling jars.
Formation of crystals
Mixture cooked too slowly or too long.
Cook at a rapid boil. Remove from heat immediately when jellying point is reached. Make small batches at a time; do not double tested recipes.
Bubbles in Jam
Air becomes trapped in hot jelly
Remove foam from jam beforetransferring jars. Prevent jam from gelling until the jars are full
Bubbles in Jam
May be signs of spoilage. Discard
Check sterilization procedures
Jam too soft
Overcooking fruit to extract juice
Avoid overcooking as this lowers the capacity of pectin to gel the jam
Jam too soft
Using too much water
Use only the amount of water suggested, start will less and add as needed.
Jam too soft
Incorrect proportions of juice and sugar
Follow the recipe. Don't halve the sugar as it will interfere with the setting
Jam too soft
Undercooking so the sugar is not concentrated
Cook the fruit quickly to jellying point.
Jam too soft
Insufficient acid.
Add some lemon juice as ripe fruit has too little acid
Jam too soft
Being Impatient, and not waiting long enough for the jam to set
8. Some fruits take up to 2 weeks to set up completely; plum jelly and jellies or jams made from bottled juices may take the longer time.
Jam too watery
Too much acid in the juice makes pectin unstable
Maintain proper acidity of juice, add sugar
Jam too watery
Storage are too warm
Store processed jars in a cool place. Refrigerate before using
Jam too Dark
Overcooking sugar and juice.
Avoid long boiling. Best to make small quantity of jam and cook rapidly.
Jam too Dark
2. Stored too for long or at a high of temperature
Store processed jars in a cool place and use within one year
Cloudiness or milkiness in the Jam
Green fruit (has starch that causes cloudiness
Use firm, ripe fruit - slightly underripe.
Cloudiness or milkiness in the Jam
Jam allowed to stand before pouring into jars or pouring too slowly
3. Pour into jars immediately upon reaching gelling point. Work quickly.
Mold or Fermentation (Denotes spoilage; do not use.)
Yeasts and mold grow on jam
Pre-sterilize jars by immersing for 10 minutes in boiling water
Mold or Fermentation (Denotes spoilage; do not use.)
Imperfect sealing and storage in warm areas
Use proper lides that seal proerly and can be sterilised. Store in cool place.
Too stiff or clumpy
Follow insructions
Too stiff or clumpy
Too much pectin in fruit or added
Use riper fruit. Decrease amount of pectin added
Too stiff or clumpy
Too little sugar which requires excessive cooking and loss of moisture
When pectin is not added, add 3/4 cup of sugar for each 1 cup of juice for most fruits

© 2013 Dr. John Anderson


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    Dil Vil 4 years ago from India

    Informative hub, it is useful. The pics are really cool. Thanks for the share!