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Jam and Jelly FAQs: Answers to Common Questions About Making and Canning Jams and Jellies!

Homemade jam and jelly is one of the easiest foods you can "can" at home, but even so, there are some problems that people occasionally encounter.  Sometimes even when you follow recommended, lab-tested, up-to-date directions, something goes wrong. A jar doesn't seal, liquid is lost out of the jar, and the fruit is floating! So what went wrong?

Here are questions and answers to trouble-shoot common canning issues. Just scroll down this page!

Other pages with related information:

Jams and Jellies

Can I make a small amount of jam and just put it in a jar, let it cool and put it in the refrigerator and start eating out of it without canning it?

Absolutely!  Canning is only needed if you intend to store it outside of the fridge!

Why can't I just fill the jars with hot jam, seal them and turn them upside down?

Word for word, from the USDA's labs:

"Some other methods of sealing jars call for inverting a closed, filled jar of hot product for anywhere from thirty seconds to one hour. (Inverting is turning the filled jar upside down on its lid.)

While this inversion process can be successful in producing a sealed jar, it works best with very hot product. Individual variation in practicing this process or unexpected interruptions can result in delays between filling jars, getting lids screwed on, and inverting the jars. If the product cools down too much, the temperature of the product can become low enough to no longer be effective in sealing jars or preventing spoilage.

When the inversion process does work, the vacuum seals of filled jars still tend to be weaker than those produced by a short boiling water canning process. A weak seal is more likely to fail during storage.

In addition, the headspace of the jar may retain enough oxygen to allow some mold growth if airborne molds contaminated the surface of the product as the jar was filled and closed. More complete removal of oxygen from the headspace also offers some longer protection from undesirable color and flavor changes with some types of fruit products. The canning process is therefore a more foolproof method of making jams and jellies that will not spoil.

Also, although no cases of burning have been reported in the news media, experience has shown that some people will experience leaking of the hot product from the jar when it is turned over if the lid wasn't put on just right. If hot enough, someone could get burned. Even if it doesn’t cause burns, leaking means product is lost."
Elizabeth L. Andress, Ph.D., Professor and Extension Food Safety Specialist. The University of Georgia and Ft. Valley State University, the U.S. Department of Agriculture and counties of the state cooperating.

I see some mold growing on my jam.  Can I just scoop it out and eat the rest of the jar?

For many years, many people, including me, just scraped off the mold and ate the rest.  But just as you have heard about the cancer-causing effects of aflatoxin molds in peanut butter, a similar mold grows in jam.  Here is the response, verbatim from the USDA and U.Ga.:

"The best answer is that there is a potential risk. However, we want to make a recommendation that minimizes all potential problems and hazards. Some molds growing on fruit products made at home have been shown to produce "mycotoxins", or mold poisons. The danger to humans from consuming mycotoxins, as well as the actual expected incidence of mycotoxins from moldy jars of jams, are issues with no easy answers.

But, animal studies indicate there is the potential for poisonous effects of some mycotoxins in humans. Patulin is one mycotoxin detected in a few tested jars of homemade apple jam and juice. Patulin has been shown to be carcinogenic in animals, but its role in causing human disease is not all that clear. It is also difficult to assess the actual health risk from consuming moldy jam or jelly because not all molds produce mycotoxins, and molds which do produce them vary in consistency of production when conditions change some. Elizabeth L. Andress, Ph.D., Professor and Extension Food Safety Specialist. The University of Georgia and Ft. Valley State University, the U.S. Department of Agriculture and counties of the state cooperating. "

Should jelly be boiled slowly or rapidly?

Jelly should be boiled rapidly since long, slow boiling destroys the pectin in the fruit juice.

Can I make a double batch of jelly?

NO. 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.

Why is my jam too runny?

The following can cause soft jam:

  • overcooking,

  • processing too long,

  • too little pectin,

  • incorrect proportions of sugar and juice,

  • undercooking,

  • insufficient acid, or

  • making too large a batch at one time.

Could you tell me why my JAM is thicker then the store bought?

The natural pectin content of fresh fruit varies, so it is possible the the variety of fruit that you used has more natural pectin, making it thicker. But there's an easy answer - just add less pectin next time. You'll have to experiment to find how much pectin makes the consistency you like. Most people seem to like their jam thick, so you may to need to only use 3/4 of a pack of pectin per batch. 

I made some raspberry jam about 3 weeks ago and I noticed about 6 of my jars did not set properly. They are very runny! With this amount of time that has gone by can I re-do the jars again?

Yes, you can remake the jam later. 3 weeks isn’t so long, so the quality shouldn't be diminished by much. - just see this page for directions: http://www.pickyourown.org/how_to_fix_runny_jam.htm

Why is my jelly soft?

The following can cause soft jelly:

  • overcooking the fruit to extract the juice,

  • using too much water to extract the juice,

  • incorrect proportions of sugar and juice,

  • undercooking causing insufficient concentration,

  • insufficient acid,

  • not enough pectin or

  • making too large a batch at one time.

Can I use frozen fruit to make jams?

Absolutely!  I usually freeze a dozen quarts of strawberries after I go picking!  I wash them, hull them and slice them in half, then freeze them in heavy-duty Ziploc freezer bags (squeezing as much of the air out as I can, or using a vacuum FoodSaver and the vacuum bags.  That way I can use those strawberries together with fruits that I pick later in the season, like blackberries, raspberries and blueberries to make mixed berry jams.  You can use the frozen (without added sugar) fruit just the same as fresh.  Just defrost them right before you use them.

I have a question about canning and Making Jellies. I am making Pear and grape jelly from the fruit we grow and I use a pressure cooker! Could this be why my jellies are not setting up? I make my jelly and Put the cans into the cooker until it hits 220 Degrees and take it off the stove. Could I be over heating the pectin so my jellies will not set correctly?

Probably – they’re being exposed to too much heat for too long; I’d expect the pectin is breaking down.  Just leave the valves open and use the pressure canner as a water bath canner!

Can anyone tell me why my jelly sometimes has bubbles in it after it has cooled down?

Bubble are trapped air or water vapor.  When the jam is boiling, the bubbles rising from the bottom of the pan and air mixing at the surface become mixed in the jam.  If the viscosity of the jam is high enough, the bubbles cannot break free.  The foam produced is the portion that has the highest viscosity - this is when we suggest to skim off the foam. Many people add 1 teaspoon of butter or margarine to the jam before they start to cook it.  This helps prevent the bubbles from forming. Exactly why, I can't tell you (it's been too many years since my fluid mechanics class in chemical engineering) - it probably has to do with disruption the surface tension or hydrophilic bonding; but the point is, it seems to work. Another method is to allow the jam to sit undisturbed for about 5 minutes after you remove it from the heat, then skim off the foam and jar the remaining jam and process it in your boiling water bath.

I just picked a boatload of wild raspberries, which are now in my freezer. Do I need to remove the seeds? If so, how do i go about doing that? The seeds are so small!

Yep, the seed-to-fruit- ratio is especially high in the wild berries.  I just made a batch of seedless raspberry jam yesterday. The easiest way to de-seed them is to use a food mill with a fine screen (they pass through the standard manual Foley food mill).  The Villaware and Roma brands have a fine screen that works – see this page: http://www.pickyourown.org/canningstrainers.htm They’re more expensive than a Foley food mill, but they come with screens of different sizes, you can add a motor later to them, and they’ll work to make applesauce, fruit butters, spaghetti sauce and seedless jams / jellies.

What makes jelly cloudy?

One or more of the following may cause cloudy jelly:

  • Pouring jelly mixture into glasses too slowly.
  • Allowing jelly mixture to stand before it is poured.
  • Juice was not properly strained and so contained pulp.
  • Jelly set too fast-usually the result of using too-green fruit.
  • Artificial sweeteners (Splenda, Stevia) don’t dissolve completely or cause flocculation or micro-bubbles.

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

Why do crystals form in jelly?

Crystals throughout the jelly may be caused by

  • too much sugar in the jelly mixture, or
  • cooking the mixture too little, too slowly, or too long.

Crystals that form at the top of jelly that has been opened and allowed to stand are caused by evaporation of liquid.

Crystals in grape jelly may be tartrate crystals. (and that's fairly normal, and harmless)

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

What causes jelly to be too soft?

One or more of the following may be the cause: Too much juice in the mixture. Too little sugar. Mixture not acid enough. Making too big a batch at one time.

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

What makes jelly syrupy?

  • Too little pectin, acid, or sugar.
  • A great excess of sugar can also cause syrupy jelly.

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

What causes weeping jelly?

  • Too much acid.
  • Storage place was too warm or
  • storage temperature fluctuated.

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

What makes jelly too stiff?

  • Too much pectin (fruit was not ripe enough or too much added pectin was used).
  • Overcooking.

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

What makes jelly tough?

Mixture had to be cooked too long to reach jellying stage, a result of too little sugar.

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

What makes jelly gummy?

Overcooking.

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

What causes fermentation of jelly?

Too little sugar, or improper sealing.

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

Why does mold form on jelly or jam?

Because an imperfect seal has made it possible for mold and air to get into the container.

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

What causes jelly or jam to darken at the top of the container?

  • Storage in too warm a place.
  • Or a faulty seal that allows air to leak in.

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

What causes fading?

  • Too warm a storage place or too long storage.
  • Red fruits such as strawberries and raspberries are especially likely to fade.

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

Why does fruit float in jam?

Fruit

  • was not fully ripe,
  • was not thoroughly crushed or ground,
  • was not cooked long enough, or
  • was not properly packed in glasses or jar.

Use appropriate procedures to prevent floating fruit.

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

How can floating fruit in jams and jellies be prevented?

After jam or jelly is boiled hard, remove from the heat and skim and stir alternately for 5 minutes to help prevent the fruit floating.

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

How can jam and jelly be tested for doneness?

There are three methods:

  1. SPOON OR SHEET TEST. Dip a cool metal spoon in the boiling jelly mixture. Then raise it at least a foot above the kettle, out of the steam, and turn the spoon so the syrup runs off the side. If the syrup forms two drops that flow together and fall off the spoon as one sheet, the jelly should be done. This test has been widely used; however, it is not entirely dependable. I usually hold an ice cube against the bopttom of the spoon for a minute to cool the jam, then tilt the spoon to see if it runs off or has gelled.
  2. TEMPERATURE TEST: Before cooking the jelly, take the temperature of boiling water with a jelly, candy, or dee-fat thermometer. Cook the jelly mixture to a temperature 8F higher than the boiling point of water. At that point the concentration of sugar will be such that the mixture should form a satisfactory gel.
  3. REFRIGERATOR TEST: Pour a small amount of boiling jelly on a cold plate, and put it in the freezing compartment of a refrigerator for a few minutes. If the mixture gels, it should be done. During this test, the jelly mixture should be removed from the heat.

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

What types of acids can I use for fruits low in acid?

Lemon juice or citric acid can be used to decrease the pH.

How much crystalline citric acid can be used in place of lemon juice?

One-eighth teaspoon of crystalline citric acid is equivalent to each tablespoon of lemon juice.

Reference: How To Make Jellies, Jams, and Preserves At Home. United States Department of Agriculture. Extension Service. Superintendent of Documents, Washington, D.C. Home and Garden Bulletin Number 56.

 

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