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Are you wondering why after canning your jars have less liquid in them than when they went into the canner? Learn what causes liquid loss during canning and how to avoid this common home canning problem in your kitchen.
Dealing with liquid loss during canning is one of the most common canning problems I’m asked about.
It can feel so frustrating to work hard to put up food and then after your jars have cooled down you notice they have a lot less water or syrup than when you had filled them.
If you may be wondering why do I lose liquid when pressure canning or water bath canning? There are some simple causes and the good news is they are very easy to fix.
Is It Still Safe To Use If The Jars Lost Liquid?
According to the guidelines from the National Center for Home Food Preservation, home canned food that has had some loss of liquid but the jars have sealed is still safe to use. But the food above the liquid level may become discolored in time.1
If your jars have had extreme liquid loss, defined as half of the liquid in the jar or more bing loss then the food may not have been processed properly. If this happens place the jar into your refrigerator to use in the next 2 to 3 days.
Why Is Severe Liquid Loss A Problem?
Safe canning times are based on how long it takes the food to reach a specific temperature to kill bacteria. How long this takes depends on the density of the food.
Liquid loss in the jar may change how the heat circulates inside the jar and cause improper processing.
What Causes Liquid Loss In Canning Jars
1. Cooling Down To Fast
Trying to cool your canning jars down too quickly is one of the most common causes of liquid loss in canning jars.
When water bath canning, after the jars have reached their processing time, turn off the heat. Then remove the canner lid and let the jars sit in the canner for 5 minutes before removing them to cool.
If you still continue to have liquid loss try increasing the time up to 10 minutes.
When you are pressure canning make sure that the canner has gone down to zero pressure naturally.2 Removing the weight too soon can cause siphoning or possibly broken jars.
Then remove the weight and let it sit for 5 to 10 minutes.
After that time has passed remove the lid and let the jars sit in the canner for another 10 minutes. After this, you can remove the jars to cool and seal.
2. Overfilling Canning Jars
It may be tempting to pack as much food into your mason jar as possible but it’s a very bad idea.
Food will expand during processing so having the proper headspace in your jar is very important. If you don’t as the food expands to take up more of the jar and cause them to boil over forcing the liquid out.
3. Changes In Pressure
When pressure canning it’s important to make sure that the pressure stays steady. Changes in pressure while canning vegetables and meats can cause the liquid to be sucked out of the jars in the canner.
If you are using a pressure canner with a dial keep an eye on it and carefully adjust the temperature to keep the pressure steady.
With a weighted gauge canner then you want to adjust the temperature to have a slow, steady rocking to the weight or as your manufacture guidelines say.
Then remember to follow proper cooling down steps.
4. Lid Problems
A common but often overlooked problem that can cause liquid loss in canning jars is problems with jar lids and wrings.
Make sure to use new jar lids and check them for any imperfections before using them. A chip or dent on the edge can prevent the lid from sealing properly.
If the ring bands are too loose they won’t hold the lid down enough. This can cause the liquid to escape the jars while being processed.
Jars with dirty jar rims will also have a difficult time forming a good seal. Make sure to wipe the jar rims clean to remove food before adding the lid.
5. Air In The Jar
Removing air bubbles after you fill your mason jar with food is important. Air bubbles can become trapped in-between pieces of vegetables or meat inside the jar.
The easiest way to release them is to use a plastic knife or spatula and run it between the edge of the food and jar.
6. Raw Packing
You may not realize that when you can raw food the food its self has air inside.
This is often why when you can peaches, pears, or even green beans after the jars have been cooled you’ll notice the food has shrunken down and appears to be floating inside the jars.
As the food shrinks during processing and air is released from the food it increases the amount of headspace in the jar.3
The extra air inside the jars can sometimes also cause discoloration of the food after a few months time.
If you don’t like how the jars look this way then doing a hot pack where the food is partially cooked for 2 to 5 minutes before filling the jars is a good solution.
7. Water Absorption
Some foods like dried beans absorb a lot of liquid as they cook. This can give the appearance of liquid being lost from the mason jar but it may not have been sucked out of the jar. Instead, the liquid was simply absorbed by the beans or other starchy food as it cooked in the jars.
To avoid this use a hot pack canning method instead.
Thankfully extreme liquid loss isn’t very common so as long as your jar hasn’t lost over half the liquid and it is properly sealed it’s still ok to use.
Do you enjoy making jams and jellies? Don’t miss these tips for fixing jelly that didn’t set.
- “National Center for Home Food Preservation | Canning FAQs.” n.d. Accessed January 23, 2021.
2. “National Center for Home Food Preservation | How Do I? Can.” n.d. Accessed January 23, 2021.
3. National Institute of Food and Agriculture. 2015. “Cooling Jars.” In Complete Guide To Home Canning, Principles of Home Canning, Guide 1:25. United States Department of Agriculture (USDA).
Kim Mills is a homeschooling mom of 6 and lives on an urban homestead in Ontario, Canada. Blogging at Homestead Acres she enjoys sharing tips to help you save money, grow and preserve your own food.