While you can easily preserve jam and jelly by pouring them hot into sterilized jars, canning (also called “water bath canning”) offers several important advantages. The good news is, you don’t always need a special canning kettle — an ordinary large pot works just fine!
What’s the Difference Between Preserving and Canning?
When you preserve, you pour hot jam or jelly into clean jars and seal them tightly with a lid. Because jam contains a lot of sugar, that sugar acts as a natural preservative.
When you can, you heat the filled jars again in a hot water bath. This extra heating kills any remaining bacteria and creates a stronger vacuum seal. That means a longer shelf life — even for low-sugar jams.
Why Should You Can Jam and Jelly?
There are several good reasons why canning is worth the effort:
- Lower sugar content: You can safely preserve jam with less sugar.
- No need to sterilize jars beforehand: The canning process takes care of that.
- Better vacuum seal: Heating pushes out trapped air, sealing jars more firmly.
Canning also gives you peace of mind: your jars are tightly sealed and safe to store for years. And you’ll almost never have to deal with mold again!
Jam and Jelly with Less (or No) Sugar
Sugar is an excellent preservative — but only when used in sufficient amounts. If you prefer a lower ratio, such as two parts fruit to one part sugar, your jam will generally keep for about six months. Want to store it much longer? Canning is the answer. Properly canned jam can stay good for several years when unopened.
If you’re using no sugar at all, or sweeteners like honey or stevia, canning becomes essential for safe preservation.
No Need to Sterilize Jars
If you plan to can your jam, there’s no need to sterilize jars in boiling water. Just make sure they’re clean — run them through the dishwasher or wash them in hot water with a bit of dish soap. Place the jars and lids on a clean towel and fill them with hot jam.
Since the jars will be heated again during canning, they’ll be automatically sterilized. That means no more fishing jars out of boiling water — saving time and reducing the risk of burns.
Better Vacuum = Longer Shelf Life
Anyone who’s made jam before knows that satisfying “pop” sound when the lids seal as the jam cools. Sometimes, though, that doesn’t happen. By canning the jars, you reheat the jam so trapped air escapes and a strong vacuum forms, extending the shelf life.
If you prefer the traditional method, you can simply re-can any jars that didn’t seal properly. If a jar still doesn’t seal after canning, there’s likely an issue with the lid or rim — check and replace it if needed.
What You Need for Canning Jam
- A canning kettle or large stockpot
- A thermometer
- A kitchen towel or canning rack
Canning Jam: Step by Step
- Fill a large pot with water and place the filled jars inside.
- Make sure the jars don’t touch each other — you can place a kitchen towel on the bottom to prevent rattling.
- Heat the water to 90°C (195°F) and maintain that temperature for 15 minutes.
- Carefully remove the jars and let them cool completely.
- Once cool, check if the lids are concave — that means they’ve sealed properly.
If a jar hasn’t sealed, store it in the refrigerator and use it first.
Canning Without a Canning Kettle
No canning kettle? No problem! A large stockpot or soup pot works just as well, as long as you can maintain the correct temperature. A digital cooking thermometer helps ensure accuracy.
Some people even can in the oven: place the jars in a baking dish with about 1 inch (2.5 cm) of water and heat at 265°F (130°C) for 30 minutes.
Shelf Life and Storage
Properly canned jam keeps for at least two years when stored in a cool, dry, and dark place. Always check the vacuum before opening — a good seal means the lid is slightly concave.
If you notice mold, bubbles, or an unusual smell, it’s safest to discard the contents.
A Few Delicious Jam & Jelly Recipes



Waterbath Canning and Botulism
Botulism is a rare but serious illness caused by Clostridium botulinum. Thankfully, we don’t need to worry about it when making jam or jelly. The bacteria can’t survive in acidic environments, and fruit naturally contains plenty of fruit acids — even if they’re masked by sugar.
So as long as you work cleanly and seal your jars properly, the risk of botulism in fruit preserves is virtually zero.
For more information, see the official CDC page on botulism.
Why Wanning is Worth the Effort
Canning takes just a little extra time but pays off in many ways: safety, sustainability, and the deep satisfaction of a pantry filled with homemade preserves. Your jam stays good for years, even with less sugar — all without artificial additives.
