Canning Dos and Don'ts (but Mostly Don'ts)
If you're considering canning for the first time, learn from my mistakes. Here's what I learned in my first attempt at making strawberry jam.
Do's
Get a canning rack. The canning rack would have made it much easier to immerse the cans in the boiling water. Instead I had to pick up each jar and gently drop it in the hot water without letting it hit hard on the bottom of the pot, or fall over once in the water. The plastic coating on the jar lifter provided the grip required to lift heavy jars, but it stuck to the jars a little on release. This caused a few of my jars to tip over in the water, and righting them was a challenge.
Get a candy or deep-frying thermometer, one that clips to the side of the pan. Per the manufacturer's instructions, I needed to keep the lids soaking at 180 F and not allow them to boil. Boiling causes the sealing compound on the lids to set. This is also why you cannot re-use jar lids. I wish I'd had that thermometer -- it's hard to look at water and know when it's just about to boil.
Get a canning kit. Almost everything I needed was in my Presto 7-Function Canning Kit. Not only did I use everything except the jar wrench (which will come in handy when I want to open my finished product) but the cool magnet on the back of the spatula was perfect for moving hot lids from the water bath to the tops of the jars. No added bacteria, no blistered fingers.
Don'ts
Run out of jars. The penalty is jam you'll have to throw out, or freeze and use within the next few months. I wasn't sure how much jam I would have left
after reduction, so I just prepared enough jars to contain the
volume of pre-cooked ingredients. Here's how that calculates:
2 Qts. strawberries (4 pints) + 3 cups sugar (1.5 pints) + 3 cups honey (1.5 pints) = 7 pints
All the resources I checked warned against cooking up the jam in large
batches. They said that for some reason the sugar doesn't get
distributed and the mixture won't ever jell.
Go outside the recipe. In an attempt to make healthier jam, I didn't use the sugar (just the honey). Unfortunately this meant the jam had to cook forever to jell, and the beautiful red strawberry color turned to a ruby merlot. It tastes good, possibly tangier than if I'd used all the sugar, but it's more like preserves than jam.
If you have tips you'd like to share or questions you'd like answered, please send them in and I'll address them in my next post.
--Martha Snodgrass
For more canning tips and tools check out Amazon's Canning Store.
Anita / Married with dinner on July 06, 2009 at 01:47 PM
I'm not saying I've never tinkered, but you really aren't supposed to tweak the recipe.
Sugar is more than just a sweetener; it's also (as you noted) a gelling agent. But more importantly, as I understand it, high sugar content is a preservative. You can safely make changes like using different fruits with similar sugar and water content (e.g. strawberries to blackberries) but you really can't safely tinker with sugar or acid.
Anita / Married with dinner on July 06, 2009 at 01:51 PM
forgot to add: if you want to make a low-sugar jam, there are plenty of tested recipes out there. but please don't wing it.
Elise on July 06, 2009 at 01:53 PM
I've made low sugar jams, using special extra strong pectin. But the jams with the third less sugar only last around 6 months instead of a couple years. You can also get away with using less sugar if the jam is a freezer jam, in other words, you store it frozen.
As Anita mentioned, sugar is a preservative, you need it if you want your jams to last, and to be safe to eat.
Marisa on July 06, 2009 at 02:00 PM
Anita and Elise are right on, you never want to alter a canning recipe (at least if you intend it to be shelf-stable) that drastically, as the sugar is a large part of what keeps your jam safe. If you do want to make your jams more "natural," you can opt for cane sugar in place of white sugar.
If you do want to go the all-honey route, there's a good book called Putting Up With Honey. Check that for guidance.
Lincoln Hyde on July 14, 2009 at 11:18 AM
I need to add to the above comments. Please use or destroy the jam you made - it is not safe. As Anita said, sugar is a preservative; it also changes the consistency of the product, so that the heat may not have been carried to the center of the jar, and your jam may not be sterile.
Some years ago, I was doing chili in a professional cannery, and one of the participants had found a chili recipe which only needed to be cooked for 15 minutes. Unfortunately, his recipe didn't have beans - our chili with beans needed the extra 30 minutes to conduct the heat throughout the product.
Kim on August 04, 2009 at 06:18 PM
Can I prepare my green beans in the jars and pressure can them the next night?