Why You Should Always Water Bath Can Your Jams and Jellies
One of the best parts of growing your own food is being able to put it away for the future. Homemade jams and jellies are easy to make and let you preserve Mother Nature’s abundance, but there’s a good chance you’re doing it wrong and not even realizing it. A Water Bath will make all the difference in the length of time your jams and jellies will last.
You cook the jam, ladle it into hot jars, screw on the lids, flip the jars upside down on the counter, and wait for that satisfying little pop. Or maybe you just fill the jars, put the lids on, and let them cool. The jars ultimately seal, and the jam/jelly always looks and smells fine, so what’s the problem?
The issue isn’t always whether the jar seals. If you’re not water bath canning, then there’s a chance that you’re sealing things you don’t want in there with your jam or jelly.
Why Inversion and Open Kettle Processing Don’t Work
The “open kettle” and inversion methods have been around for generations. You fill your jars with hot jam, put on the lids, and either flip them upside down for a few minutes or just let them cool right-side up. The heat is supposed to sterilize the headspace and seal the jar as it cools.
To be fair, both of them work in some instances (very high-acid, high-sugar jams with good moisture control). The problem is that “often works” and “works all the time” aren’t the same thing, and when you’ve spent days picking and cooking down local peaches, you’d really like to know which one you’re dealing with before you open a jar eight months from now.
Molds Don’t Care How Hot Your Jam Was
Even if food safety isn’t a concern with a high-acid jam, mold still is, and mold is airborne. When you’re ladling hot jam into jars in your kitchen, mold spores from the air are settling onto every surface, including the inside of your jars and lids. While the heat of the jam may knock out a lot of it, the retained heat from hot filling by itself isn’t usually enough to kill the spores floating in the headspace.
Commercial canning companies inject superhot steam into the headspace just before the lid goes on. You don’t have that in your kitchen, and neither does anyone else canning at home.
What you do have is a water bath canner. The boiling water process gets that headspace hot enough to kill mold spores.
Not All Vacuum Seals Are Equal
You know that satisfying pop when a lid seals? It means the jar is sealed, but it doesn’t tell you how well.
Vacuum seals aren’t all the same. A stronger vacuum means more air (and more oxygen) was removed from the headspace before the lid set. A weaker vacuum means there’s more trapped air, which can mean color changes, loss of flavor, and a shorter shelf life.
The inversion method creates a seal through the heat as the jar cools, but it’s inconsistent, and it doesn’t usually create as strong a vacuum as a water bath does.
When you process jars in a boiling water bath, the heat causes the contents to expand and forces additional air out of the headspace. When the jars cool after processing, that expanded headspace contracts, pulling the lid down into a tight, deep seal.
The Inversion Method Doesn’t Work as Well as You Might Think
Inversion works when everything goes just right, but when does everything go exactly as you planned? Murphy’s Law always seems to be at work.
The National Center for Home Food Preservation reports that leaking and seal failures are higher with inversion than with water bath processing. There’s also the risk that you’ll burn yourself when you’re flipping heavy jars of 220-degree jam with a towel in each hand.
More importantly, inversion depends on the product staying hot enough during the entire process to do its job. If you’re working through a large batch and the first few jars have been sitting for a few minutes while you fill the rest, the temperature has already dropped.
Not all jams and jellies are equal here, either. Some things (think lower sugar recipes and anything with reduced acid) might need a longer water bath process than even a standard recipe calls for. The inversion method doesn’t let you do that.
What Does the USDA Say About It?
The USDA recommends water bath processing for all home-canned jams, jellies, and highly acidic fruit products, with no exceptions, because inversion isn’t as reliable across every kitchen and every gardener. Go ahead and spend that extra 10 minutes for a little more food safety.
Learn It Right the First Time
If you’re newer to canning or you’ve been doing it the old way and want to learn how to do water bath processing, we’d love to have you in the kitchen with us.
We offer Canning 101 classes here at Stoney Creek Farm. They’re hands-on, two-hour sessions where you’ll work through the process start to finish: equipment, prep, filling, processing, and what to do when something doesn’t go the way it’s supposed to.
Can’t make it to the farm? Our Canning 101 Online Course covers everything in the same depth and lets you work through it at your own pace from wherever you are.
Safer Canning Is Better Canning
Preserving your own food is one of the most satisfying ways to control what goes into what you eat and to honor what nature gives us. You chose the fruit, sliced and peeled everything, made the recipe, and filled the jars. The water bath canner is just the last step in a process you’ve already committed to doing well.
Yes, it does take a few extra minutes, but if you’re putting food up for the future, knowing that you did that little bit more to help prevent mold and early spoiling is more than important. Your pantry (and your family’s access to healthy, home-made food) is worth that extra 10 minutes.
