I use the open kettle method. I sterilize glass jars, pour boiling hot preserves in them and immediately screw on Plastisol lined lug lids while the preserves are piping hot and let them cool on a rack. This method has its critics, but I’ve never had a problem with seal failure or a consumer becoming ill. I would not use the open kettle method for anything other than fruit. I buy my jars and lids at SKS Glass Company.
For the preparation of most fruits, I macerate them in sugar and lemon juice and make a pectin bag with the peels, seeds and membranes of the lemons I juiced for the preserves. Sometimes I add some green apple skins and seeds if the fruit is particularly low in pectin and I don’t want an overwhelming lemon flavor. I bring the macerated fruit and pectin bag to a simmer, and immediately put everything in a ceramic dish or heat proof plastic container. I cut a piece of parchment to snugly fit on top of the fruit, put on the lid of the plastic container or wrap it in plastic wrap and let the fruit macerate overnight in the fridge. This technique accomplishes a few things. It allows the fruit to absorb some sugar, which helps it retain its shape in the final product. It makes it easier to skin the fruit if you are so inclined. It also allows the pectin to leach out of the fruit and the contents of the pectin bag, assuring a better jell.
I use an unlined copper preserving pan, which also has its critics. However, unlined copper has been and is still used by many people for preserving and candy making. Just make sure to clean the tarnish off the copper before every use. I pour some salt and vinegar into the pan and scrub it with a sponge. Some people add flour to make a paste. When you’re done scrubbing, the copper should have the original pale pink color and sheen. If you look at the picture in this post you will see that the top and inside of the pan is lighter, pinker and shinier. That’s because I just cleaned the inside and the outside is tarnished. That’s the way the inside should look before you put your fruit in the pan.
I buy my pectin bags on Amazon. I buy unbleached food grade cotton muslin with a drawstring. Mine are about 7″x9″ and that’s about the right size for up to 3 kilos of fruit.
I have a wooden spoon that I only use for preserving, so that it doesn’t harbor other flavors or bacteria.
I use a heat proof, Borosilicate spouted glass measuring cup with a spout and handle so that I can pour the preserves into the jars without using a funnel.
I use a food mill with assorted discs for certain preparations.
I line my rimmed baking sheets with a Silpat so the jars don’t slide around.
I use a stainless steel ladle to ladle the jam into my glass measuring cup.
I sterilize my jars, the ladles and the glass measuring cup in a 225 degree fahrenheit oven for 10 minutes and I just leave them in the oven until it’s time to fill the jars. Do not put the lids in the oven or in hot water or you will destroy the seal.
I use a wooden skewer to remove air bubbles in the preserves after they are in the jar. You just stick the skewer in the side of the jar and give it a little wiggle to make sure the preserves have settled into the jar without leaving air pockets.
I use a laundered, lint free dish towel, dampened with hot water to wipe the tops of the jars to remove any spilled preserves.