Part of the joy of growing your food is being able to preserve it for eating during the dormant season. But canning can be a challenge.
Fortunately, canning, like gardening, is a skill that you can develop. At first, you might encounter several common canning problems and wonder how to fix them. Over time, you'll learn how to deal with challenges and have fewer issues and errors. That comes with practice and making the mistakes so that you learn how to avoid them in the first place – and by reading this guide.
When I first started canning, I made a bunch of mistakes. My jams didn't set, soup leaked out of the top of the jars, and half of my lids didn't seal. At times, I wonder if I was meant to can the food from my garden. My grandma, who spent years canning in her childhood, encouraged me to keep trying. As I kept at it, my mistakes lessened over the years.
I know how it feels to have a botched canning job, so I'm making things easier for you by rounding up the most common canning problems and how to solve them.
7 Most Common Canning Problems
1. Canning Jars Didn’t Seal
One of the most common canning problems is jars that don’t seal. Nicks in the jar rim, food residue, overflowing jars, and more can stop the lids from sealing properly.
The food isn’t lost forever if you find out quickly that the jars didn’t seal correctly. If it’s after 24 hours, you’ll need to discard the food due to the risk of spoilage and bacteria growth.
How to Fix Jars That Don’t Seal
If the jar doesn’t seal, you can remove the lid and reprocess the contents within 24 hours. While the food is processing, use that time to determine what went wrong.
Examine the jar to see if there are any nicks in the rim. When you lift the lid, see if there any food particles leftover on the rim of the jar. Check to see if you left enough headspace between the food and the bottom of the lid. Food that comes out during the process can stop the top from sealing correctly.
Prevent Jars From Failing To Seal:
- Before you fill the jars, make sure you thoroughly examine them. Look for any cracks and nicks that might cause the jars to break or stop the lids from sealing properly.
- Check the recipe to figure out the right headspace that must be left between the lid and food. The canning kit should have a measurer used to find out the right headspace.
- After you fill the jar, use a clean washcloth to wipe down the rim around the jar.
- Don’t screw the rims on too tightly. Screw them on to fingertip tightness.
- Make sure you use a brand new lid each time. Lids are not reusable for canning.
2. Jam or Jellies Are Runny
I’ve messed up several batches of jams and jellies. Instead of coming out ready to smear on a sandwich, I end up with syrup. Runny jam can be recooked with additional sugar and pectin to make the right consistency.
Runny jams and jellies are usually because you cooked them wrong. You might not have used enough pectin or sugar. Remember to boil the jams and jellies for a specific time after you add the pectin and sugar to help set the jam.
How to Prevent Runny Jams and Jellies
Before we talk about how to fix the runny jam, let's look at how to prevent it from happening in the future.
- Make sure you use the widest pot you have available to ensure it has enough height to let the jam boil vigorously. More surface area helps with the evaporation process, so the water from the fruits are evaporated out of the jam faster.
- The ideal set point is 220℉. Jam is like making candy; you need to apply the right amount of fruit and sugar to get to that temperature. Too little sugar will prevent you from reaching the proper temperature.
- Use the plate test. Before you start to cook, put a few plates in your freezer. When you think the jam is ready, take one of the plates and put a small spoonful of the jam in the center. Let it sit for a few moments, then push on the jam with your finger. If it’s formed a skin and seems to develop solidity, it’s ready.
- Adding the right amount of pectin matters as well, but pectin isn’t the make or break determinate of the successfulness of your jam.
How To Fix Runny Jams and Jellies
Already have jars of runny jam? Don't worry; you can fix it! Wait 24 hours to give the jam time to set up. Sometimes, pectin can take a while to set. Then, if it still hasn't set, you'll want to measure out how much jam to recook. You shouldn't remake more than 8 cups at a time.
- For every 4 cups of jam, mix ¼ cup sugar and one tablespoon powdered pectin.
- Put the jam into a low, wide pan, and add the sugar and pectin mixed. Stir until everything dissolves.
- Bring the jam to a boil and cook vigorously for 5-10 minutes, stirring regularly.
- Use the plate test to make sure it’s set better this time.
- Put the jam into clean jars and process the same way you did before.
3. Liquid Came Out During Processing
Losing fluid during processing isn't a sign of spoilage, and you don't need to open your jars to replace the liquids. If you lost half of the fluid in your jar, then you should refrigerate the jars and use the contents within two to three days.
Issues That Cause Liquid Loss
Several issues cause this common canning problem, such as:
- The pressure inside of the canner suddenly lowers after the processing period.
- You left air bubbles inside of the jars.
- Fluctuating pressure during the processing inside of the pressure canner.
- You didn't place the ring bands on tight enough.
- You didn't fully cover the jar with water in the boiling water bath canner.
- An improper seal.
- You packed the food too tightly into the jars, causing it to boil over during the processing.
How to Fix Liquid Loss During Canning
Since a multitude of issues can cause the loss of liquid, determine what caused your problem this time. Then, follow these tips to stop it from happening again.
- Before placing the lids on the jar, make sure you use a plastic knife or spatula to remove any air bubbles from the food contents.
- Measure the appropriate headspace for whatever you’re canning. Follow the recipe! Then tighten the bands on the jar fingertip tight. Don’t over tighten them.
- Allow the pressure in your pressure canner to drop naturally, and wait 10 minutes before opening after the weight is removed from the lid.
- Actively maintain a constant temperature during the processing. That means you need to pay attention while it’s canning.
- If you’re using a water bath canner, make sure you cover the jars with 1-2 inches of water.
4. Food Darkens at the Top of the Jar
Sometimes, you might notice the food at the top of the jar is darker. That doesn’t mean the food is spoiled. Darkened food is an unappealing sight but not dangerous for you to consume.
Darkened food is caused, usually, by air. You might have left too much air in the jar, resulting in oxidation. If you didn’t use enough liquids or syrup, that leaves too much air as well. Another cause of darkening food is that you didn't process the food long enough to destroy the enzymes.
How to Prevent Darkening Food
Preventing darkening food in the jars is one of the easiest canning problems to fix. Here is what you need to do.
- Make sure to know the recommended processing time for the recipe that you’re using.
- Fully cover whatever you’re canning with water or syrup.
- Make sure to remove any air bubbles before sealing the jars and use the recommended headspace based on the recipe.
5. Cloudy Liquid In the Jars
Another canning problem that you might experience is cloudy liquid, which might mean that the food is spoiled. It depends on the reason why you have cloudy liquid in the jar.
The cloudy liquid can be caused by spoilage, but it's caused by the fillers in table salt or the minerals in your water. Also, the starch in vegetables can create a cloudy look to the liquids in your jar.
How to Prevent Cloudy Liquid
Luckily, it's not complicated to prevent cloudy liquid in the jars. Always make sure that you select vegetables that are at the right stage of maturity. Over-mature vegetables are more likely to cause opaque liquids.
A few other steps to prevent cloudy liquids in your jars include:
- Use soft water to fill your jars.
- Use pure, refined salt instead of table salt.
- Follow the recommended canning process, methods and times.
6. Floating Fruit
Do you have floating fruits in your jars? Overprocessing fruits and tomatoes can destroy the natural pectins in the fruit. Another reason that fruit might float is that the fruit is lighter than the sugar syrups or it was improperly packed.
How to Fix Floating Fruit
If you notice floating fruit, it’s an easy fix. The most important thing is that you follow directions for processing times to avoid overprocessing the fruits because they're delicate.
Also, make sure that you use firm, ripe fruit. Heat the fruit before packing. Unlike vegetables, you shouldn't raw pack fruits. Use a light or medium syrup, and be cautious when you pack the fruit to avoid crushing them.
7. Spoiled Jars of Food
The last of the most common canning problems many people face is spoiled jars of food. It feels horrible to find jars of food that you spent time canning full of rotten food. I’ve had it happen, and it leaves you wondering if canning is worth all of the time and effort.
The spoiled food means that you made a mistake somewhere along the line. Pinpointing that mistake is vital. The most common reasons for food spoilage are:
- Incorrect pressure
- Incorrect processing temperature
- Wrong processing time
- Bad fruits and vegetables
How to Prevent Spoiled Jars of Food
First, always check over your equipment each year for damage. Make sure to test the dial gauges for accuracy. Follow researched-based recommendations for canning food, and follow directions for canners and timing of processes. Always check the jar and lids for defects.
Make sure that you always can low acid vegetables and meats in a pressure canner for safety. A pressure canner will kill off any botulism spores. Fruits and pickles can be canned in boiling water, and that includes jams and jellies.
Practice Makes Perfect
Canning is a skill that you work on perfecting, just like gardening. Making mistakes is part of improving that skill, so don't lose hope when you make one of the most common canning problems. Learn how to fix and prevent these mistakes so your canned goods will last for years in the pantry.