Several of you have emailed me with various questions related to jam. Most of them are in the vain of "Is jam making hard?" "How do you make jam?" "Have you made any jam recently?"
Given this line of questioning, I thought I'd write a bit about the jam making process. Although I'm still quite the novice, I have made 5 batches now and the whole process seems to get easier and easier each time. Thus, for those of you who might want to make your own jam, here is my advice and notes from what I've learned.
The jam making process is actually two separate processes; jam making and sterilization.
The first thing to do is clean and sterilize any and all tools and jars you plan to use. Wash everything; jars, lids, jar band, wide mouth funnel, ladles, jar tongs, in warm soapy water. Place a big (minimum 20 quart capacity) pot on the stove and fill it with enough water so that it will cover the jars with at least one inch of water. You don't want the jars to touch the bottom of the pot so either use a jar rack or a round cake cooling rack on the bottom of the pot. Bring the water to a boil and put the jars and bands in the boiling water. Boil for a minimum of 10 minutes to ensure complete sterilization. Take the jars out with the jar tongs and the bands (this is where a lid remover comes in handy) place them on a clean towel (this prevents thermal shock). Prevent touching them with your hands (contamination) and allow them to cool.
Make the jam. As a rule of thumb I've found the following recipe suits my taste. 5.5 cups of fruit (whatever you want), 4.5 cups of sugar, the juice and rind of 2 or 3 lemons (depending on how acidic your fruit is), one pouch of liquid pectin. Place the fruit , sugar, and lemon juice and rinds in a big pot (make sure it's big...jam foams a lot in the beginning and you don't want spillage.) Bring everything to a rapid boil and then turn down the heat until you get a rolling boil. About 2 or 3 minutes into the process mix in all the pectin. Boil for the next 10 - 30 minutes until you get the consistency you want. Remember that jam is thinner when its hot so you don't want it to the exact consistency it would be when cold. It should be a bit thinner. A good way to test the consistency is to put a small plate in your freezer before you begin making the jam. When you're ready to test take the plate out and put a small amount of warm jam on the plate. Place the plate in the fridge for about 20 seconds. Take the plate out and test the consistency. This will be the consistency of your jam. If it's still a little runny boil the jam a bit further. Once your jam is the right consistency get ready to work quickly.
Approximately 10 minutes before the jam is ready place the jar lids in the pot of hot water. Boil for 10 minutes to warm up the gummy sealant on the lids. Take the lids out of the water with the lid remover. And let them dry a bit. Avoid touching them with your hands.
Using the sterilized wide mouth funnel and ladle, ladle the hot jam into the sterilized and dry jam jars. Fill the jars to about 1/3 inch of the rim. You want to leave some space - this space creates the vacuum seal. Repeat with all the jars. Using a clean wet cloth, wipe the rims of the jars clean. Place the sterilized lids and then use the bands to the secure the lids in place. Only tighten the bands finger tight. Using the tongs place each jar in the pot so that they don't touch each other. Boil the jars for about 15 minutes. Avoid jostling the filled jars to much after this point. Once the 15 minutes are up take the jars out carefully and place them on a towel. Allow them to cool fully before handling them. About 5 minutes after the jars come out of the boiling water you should start hearing little "clinking" noises. This is the sound of the vacuum seal forming. It's a gooooood thing.
You should now have 6 beautiful 8oz jars of jam. They should last indefinitely although i've read that you should replace the lids once a year if you plan to store them for a very long time. But who can keep homemade jam around for that long!
Happy jam making...if you are so inclined!