Why Is My Jam Too Runny? (How to Reboil and Fix It)


Whether you are a novice jam and jelly maker and are just learning or are a pro who has been canning for years, occasionally, at least one will not set properly. For whatever reason, it turns out with the consistency of half-set jello. There’s no need to panic; there is always a good reason.

Jam or jelly is usually too runny because it was not boiled long enough, there was not enough pectin or alternative thickener added, or the ingredients were not measured correctly. Less likely reasons are that some water was in the jars before pouring or the batch was not allowed to set long enough.

I am a professional canner and have had this happen several times over the years and can give you some hints as to how this can be prevented and some suggestions for what you can do if it does happen.

To fix or runny jam or jelly:

  1. Pour the contents of each jar back into the pot.
  2. For six to eight, 8-ounce jars, add another 1/2 cup of sugar mixed with a half box of pectin (or 2 tablespoons of bulk pectin).
  3. Reboil jam for one minute and jelly for two minutes.
  4. Prepare the jars as you would normally and reseal.

Of course, the best way to deal with this issue is to make sure you follow a checklist when measuring and adding ingredients that should help ensure this problem doesn’t happen again. But sometimes, there just isn’t anything you can put your finger on that caused the problem. Luckily, fixing the runny batch is totally doable.

What wait! Do you really need to “fix” it?

Another idea is that if jam or jelly doesn’t set properly, you can just keep it as is.

Ideas on what to do with runny jam or jelly:

  • Spread It As Is– Runny jelly is perfectly good and actually spreads better on a sandwich or a piece of toast than fully-set jelly. Once refrigerated, the consistency will be even more firm. You can use the jelly as it is and enjoy the easy spreading.
  • Use it as a Sauce or Topping– It would make a wonderful, fruity-tasting syrup for your pancakes or biscuits, a fantastic topping for your ice cream or cheesecake, or just heat it to spread as a sauce on your pork roast.
Open Jelly Jar with English Muffin

So, think about it before you attempt to reboil. However, if you want to go forward fixing that jam or jelly, the rest of this article will tell you all you need to know to get it done.

How to Reboil Jam or Jelly That Has Not Set

Reboiling runny jam or jelly is actually straightforward and easy to do.

To reboil jam you first add more sugar and pectin in order for it to set. Typically, you want to add 1/2 cup of sugar mixed with a half box of pectin (or 2 tablespoons of bulk pectin) for six to eight jars of jam or jelly. Then reboil and simmer for 2 to 3 minutes and pour into freshly prepared jars.

Step-by-step process for reboiling jam or jelly:

1. Prepare Fresh Jars

  • Prepare your chosen type of jars as you would for any jelly by washing in hot, soapy water and rinsing well. Make sure you use high-quality mason jars and avoid the cheap ones. Here are the jars I recommend, they come with everything you need including lids and rings.
  • Place jars in a pan of water, bring the water in the pan to the boiling point and allow them to boil for the entire time the jelly is cooking, or at least 10 minutes. This will sterilize the jars.
  • Bring another pan of water to a boil, then reduce heat to simmering and place lids in that water until needed.

2. Reboil the Jam or Jelly

  • Open all the jars that did not gel.
  • Pour the jelly back into your jelly-making pot, or Dutch oven. I do not recommend using a pressure cooker.
  • For six to eight, 8-ounce jars, add another one-half cup of sugar mixed with a half box of pectin (or 2 tablespoons of bulk pectin). Stir until pectin is dissolved.
  • Bring to a boil, reduce to medium heat, and cook for 2-3 minutes more.

3. Pour Into Fresh Jars

  • Turn off the burner, skim any foam from the top of the jelly, and pour it into prepared jars.
  • Wipe the jar rims with a clean damp cloth before affixing lids to make sure there is nothing on the rims to prevent a good seal.
  • Affix the lids that have been in hot water for at least ten minutes.
  • Move the jars of jelly to the prepared surface and leave them untouched until completely cool.

That’s it! Your jam or jelly should be perfect!

Are There Any Types of Jams or Jellies That Cannot Be Reboiled?

Any jelly can be reboiled to obtain a firmer consistency. However, jam is more difficult to reboil because it can scorch the fruit. If your jam is runnier than you would like, only reboil it for 1 minute, stirring continuously so that it doesn’t burn.

Just remember that you may not want to try firming up jam at all. Because jam is full of fruit and naturally thicker than jelly, I don’t mind it being a softer set and usually don’t bother trying to fix or reboil it. This is because jam is full of fruit and naturally thicker than jelly.

There should not be a problem reboiling any types of jelly to obtain a better, firmer consistency. I made several batches of pepper jelly recently, one of which didn’t set as it should have. So, I reboiled that one batch, and it turned out just fine. It seemed to me that it may have been a little too firm, but the person I made it for liked it that way, so all was not lost.

Alternative Thickeners Should Not Be Reboiled

If you are making jam using gelatin or jello as a thickener, boiling gelatin for too long will weaken its gelling ability, so if it doesn’t set properly, you cannot reboil it.

jello gelatin boxes

How to Fix Runny Freezer Jam

Freezer jam can be fixed with an almost identical method to regular jam.

To fix or runny freezer jam:

  1. Pour the contents of each jar back into the pot.
  2. For six to eight, 8-ounce jars, add another 1/2 cup of sugar mixed with a half box of pectin (or 2 tablespoons of bulk pectin).
  3. Reboil jam for one minute.
  4. Prepare the jars as you would normally and reseal.

There are many different freezer jam recipes, so you may have to adjust the process a little. Some fruits are more prone to scorching, so make sure you constantly stir while it is being heated.

When You Cannot Fix Freezer Jam by Reboiling

If you are making a freezer jam recipe that uses gelatin or jello as a thickener, it cannot be reboiled, so it would be better used as is or just add a little more of your thickener. Most freezer jam recipes only make about 4 eight-ounce jars, so for that amount, you would only need to add 1 additional tablespoon of pectin.

Can I Reuse Lids from Unset Jelly?

If you have to recook jelly that does not gel, it will probably be alright to reuse your lids, but I do not recommend it. However, if you are making the jelly for your own use, go ahead and reuse the lids as you can always immediately refrigerate any jars that do not seal properly, and use those jars first. If you do reuse lids, check the stored jars of jelly regularly to make sure they have not come unsealed.

Does Runny Jam or Jelly Last Just as Long?

The consistency of jam and jelly has nothing to do with its shelf life and will last just as long as if it were set perfectly. So, not to worry, if you decide to use that runny jam or jelly just as it is or save it to make a sauce or a topping, you can rest assured that it will last for at least 2 years in your pantry.

How Long Does It Take for Jam to Thicken or Set?

There is no set answer to the question of how long it takes jam and jelly to set.  There are just too many variables. Even the weather can affect the way jam and jelly sets.  If it is raining or the humidity is extremely high, it can take longer for the jam and jelly to become firm. Most sources say that it can take between 24 and 48 hours.

Jam or jelly takes about 3 or 4 hours to set under average conditions. If you have followed the recipe exactly and have left the jars of jam and jelly alone after having finished a batch, on a dry, sunny day, they should be set by the time they are completely cool.

Having made a lot of jelly and a good bit of jam in the past few years, I have fine-tuned my process for jelly so that most jars are completely set within 1.5 to 2 hours.

Pro Tip: My process includes adding extra pectin, 4 tablespoons of bulk pectin rather than the recommended 3 tablespoons, and cooking for 9 minutes rather than the standard recipe of cooking 1 minute and then processing in a boiling water bath for 5 minutes. I leave out the boiling water bath process completely for jelly. For jam, I cook for 3 minutes and use the boiling water bath for 10 minutes. Jam is easy to burn if you try to cook much longer than that.

Even though your jam and jelly may be firm after 3 or 4 hours or if you follow my recipe for jelly and your finished product is firm in 2 hours or less, I would still recommend that you let it sit for at least 24 hours before moving the jars just to ensure you are getting the best set possible and that the lids have formed a good seal.

Important: If it isn’t set as firmly as you would like after 24 hours, I would just let it sit, undisturbed, for another day. After 48 hours or so, if your jelly or jam still doesn’t have the desired consistency, then you can decide whether to try to “fix” it, or just use it as is.

By the way, if you do not have a boing water bath canner, here is the one that I recommend.

6 Tips for Maximizing Your Chances of Jam and Jelly-Making Success

I’ve found the best way to maximize your chances of success when making any type of preserves is to use a proven process and never vary from it.

Here is what I recommend:

1. Use a Well-Tested Recipe

Jelly making is not a hit-and-miss affair. A gel is formed when the right ratio of fruit juice, sugar, acid, and pectin is combined. If you start adjusting the amount of any of the ingredients, the jelly may or may not turn out right.

Also, you cannot use the same recipe for all kinds of fruit. This is because all fruit contains some natural pectin and acid, but not the same amount. For example:

  • When making apple jelly which is high in natural pectin, the ratio of ingredients should be 5 cups of juice to 7 cups of sugar with one package of fruit pectin and no added lemon juice or any other type of acid.
  • But, when making blueberry jelly which is very low in natural pectin, the ratio should be 3 & 1/2 cups of juice to 5 cups of sugar with one package of fruit pectin and 1 tablespoon of lemon juice.

These recipes are tried and true and can be depended on to produce a good jelly when directions are carefully followed.

2. Measure All Ingredients Exactly

Use the same measuring cup for juice and sugar to ensure the proper ratio of ingredients. I recommend a measuring cup that measures all the way to the top because the hash marks on most measuring cups make it difficult to get the same exact measurement every time.

3. Cook for the Designated Length of Time

Using a timer is the best way to do this. I, for one, can’t be trusted to remember just what time the jelly came back to the second full rolling boil. In addition to the necessity for using the right ratio of ingredients to ensure the jelly sets properly, the jelly must come to a full rolling boil and remain at that temperature for a certain length of time.

Boiling Jelly Pot

4. Practice Proper Storage

Make sure the pectin has been stored properly and is fresh when used. It is best when the package is kept closed and stored in a cool, dark storage area such as a cabinet or pantry.

5. Use Dry Jars

Make sure no water has gotten into the jars before pouring the jelly. If you add a little water, you no longer have jelly, just colored and sweetened liquid. Does it sound like I know what I’m talking about? Yep, if it can be done, I’ve done it!

6. Don’t Play Peekaboo

When the jelly has been poured into the jars and lids affixed, place it in a prepared area where it can remain untouched until completely cool. In other words, leave it alone and don’t keep checking it. This is the hardest part for me. I want to keep picking it up and looking at it.

Sometimes it takes up to 48 hours for the set to be complete. So, put your freshly made jams and jellies in an area where they won’t have to be moved for a couple of days.

Small batch of jelly

What Causes Jam and Jelly to Set?

For jam or jelly to set with the right consistency, you need the correct mix of ingredients and adequate sustained heat. Ingredients must reach a hard rolling boil and the boiling must be maintained for at least one minute for the jam or jelly to set properly.

Using the Right Mix of Ingredients

Juice, sugar, acid, and pectin – There must be the right combination or ratio of these ingredients for a set to occur. 

Fruit naturally contains acid and pectin, but the amounts differ in the different types of fruit, and the amounts vary by the ripeness of the fruit. This is the reason for the different jam and jelly recipes for different types of fruit.

For example:

  • The recipe for mayhaw, apple, crabapple, and concord grape jelly is 5 cups of juice, 7 cups of sugar, and 1 box of fruit pectin because those fruits are high in natural pectin.
  • But, the recipe for blueberry and blackberry jelly is 3.5 cups of juice, 5 cups of sugar, 1 tablespoon of lemon juice, and 1 box of fruit pectin because these berries are low in pectin and need the addition of lemon juice because of low acidity.

Fruit contains the maximum amount of pectin when it has just reached the ripe stage, but as it continues to ripen more, the pectin amount decreases.

Adequate Heat

The ingredients must reach a hard boil, or full rolling boil, for the jelly to set, and that temperature must be maintained for a certain length of time.

Enough Time

The hard-boiling point must be maintained for at least one minute for a set to occur.

Summary

Making jam or jelly is a fun hobby that can last a lifetime and with experience comes perfection. If you would like to fine-tune your jelly-making process, I would recommend following all of these tips. Doing so will ensure that your jam or jelly has the best chance of setting firmer and faster, and more importantly, tasting delicious.

  1. Use a good recipe
  2. Measure exactly
  3. Cook for the specified time
  4. Use fresh pectin
  5. Make sure no water gets into the jars before pouring the jelly
  6. Give them 24-48 hours to cool and set

After it cools, if a batch of jam or jelly doesn’t set properly, there is no reason to stress over it. You can either use it as it is as an easy spreader or follow my simple directions for a quick fix and then enjoy the fruits of your labor. Enjoy the process and be sure to comment if you have ideas on how to make everything go smoother (or less smooth in this case).

For more, don’t miss How to Make Jelly, Jam, and Preserves: A Complete Beginner’s Guide.

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Anne James

Hi, I'm Anne but my grandchildren call me Jelly Grandma. I have over 50 years of experience as a Southern cook and am a retired librarian. I love sharing what I have learned. You can find me on YouTube as well! Just click the link at the bottom of your page. I hope your visit here has been a sweet one.

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