At my new house, turns out there are a ton of blackberry bushes, so now I have 2.5 quarts of ripe berries in my fridge. There is no way I can eat them all, so I want to make jam. I have the jars, the pectin, and the fruit, but I’m wondering if there are any other tips I should know. I don’t have a jar sterilizer or whatever you’re supposed to have to keep the jars hot. Can I just use a pot of water? This is my first time jammin’, so any hints would be appreciated.
Yes, you can just use a tall, wide soup pot. The jars have to be covered by about two inches of water and not crowded together. I’d also recommend investing in on of those pairs of rubber-covered tongs that lets you grab jars out of the water and a canning funnel (like a regular funnel, but about two inches wide at the opening) to let you fill the jars without getting any on the rim.
You can also just top the jam with paraffin rather than canning the jam. Make sure you sterilize the jars before putting in any jam, then pour in about a half-inch layer of hot paraffin. It’ll solidify and seal the jar, and all of it will come up and not stick to the jam.
Hmmm . . . my mom always used paraffin when canning.
I guess the advantage is that you don’t need canning jars with the special sealy-ma-jigger stuff around the lid, you can just use any ol’ jars you have hanging around.
I vill haff to sink about zis . . . I’ve been thinking of canning some stuff, but haven’t really gone beyond the idle musing stage.
Are there applications where paraffin doesn’t work? I’m thinking pickles?
Hmmm . . . on second glance, a little googling indicates that paraffin is not a very safe way to can. Sorry, I’d post links, but I’m taking off from work . . . But I had to post something or somebody might get botulism, and then I’d feel bad. 
The “Ball Book of Canning” is your basic how-to resource.
You can often buy old jars with ring lids at yard sales (small jars work best for jam, natch). Or you can buy them at most grocery stores. All you need is a fresh pack of “dome lids” (they’re really cheap) and you’re good to go.
Step 1: If your jars aren’t mint in box, sterilize them (Ball says that new jars need only be cleaned with hot water and milk soap). Putting them through the dishwasher is the easiest way to accomplish this. Otherwise boil them in water to cover 10 minutes. Those babies are now sterile! Leave them in hot water up until the time you are ready to start filling them (so they won’t get heat shocked by the hot jam)
Step 2: make your jam.
Step 2a: meanwhile boil water in a container large enough to hold all of your jars and cover them with 2 inches of water. This always happens either too fast or too slow! If you have one of those fold-out steamers, I’d put that at the bottom to keep your jars away from the heat source.
Step 3: fill your jars. A canning funnel is nice, or carefully ladle until 1/2" of space remains below the rim (this is called “head space”). Important Wipe the rims of your jars completely clean and dry.
Step 4: place a dome lid on each jar, and lightly screw on the ring lid thingy. Not too tight! Just as tight as you can get it, using the barest stregth of your fingers, until it stops.
Lift each jar and place it upright in the water bath. Boil for the amount of time recommended by your recipe (usually 10 minutes) – this is called “processing”. Remove jars and place on a towel. Allow to cool to room temperature. You may or may not hear a “pop!” as the jar seals. To test for seal, press down on the dome lid. If you feel it going up & down, it is not sealed. If it seems solid, it is sealed.
Jars that don’t seal can still be eaten, but should be refrigerated and used promptly. Do not store unsealed jars.
This is known as “hot pack” canning, because the jam is boiling hot when you can it. Be careful with that molten jam.
The other method, used for pickles and pickled things, is called “cold pack.” With that method, you stuff the sterilized jar full of raw veggies, then pour boiling vinegar over tham and process in the water bath. It’s sort of easier if you are a canning noob.
Enjoy!!
Just FYI, I have done improvised home caning, and I’ve used a canning rig. The rig really is a bit easier since it is sized and shaped for the purpose of canning, and comes with special handy tools. However, my cans sealed just as well using improvised tools.
**Hello Again ** really hit all the main points for cooked jams.
A few side notes:
-Only use the Ball/Mason/Kerr style jar with rings and dome lids. The old style with glass tops and rubber rings are cool to look at, but not as dependable for canning. However, they are desirable at flea markets and yard sales.
-Jars (if not chipped or cracked) and rings can be reused, but dome lids must be new for each batch.
-A reference was made above to botulism. I think that you’re safe with things high in sugar and acids (such as jams), or vinegar (such as pickles). Tomatoes are safe, too. Not to say that things can’t go bad, but it is by getting moldy, and you’ll see that. Things like green beans and potatoes can be dangerous, however. If the dome lid is bulging up instead of being concave, chuck it out.
-Sterilization is key. Boil anything that will come into contact with the jam itself, such as the jars, the ladle, the funnel and the lids.
-Sure-Jell has two types of pectin; their regular pectin, and one formulated for those who like to use less sugar. The Low Sugar one gives one more fruit taste, but makes for a slightly tarter jam. If the fruit is too tart to eat by itself (such as Damson Plums), you may not want the low sugar pectin, but the regular one might be fine.
-The pectin usually recommends against doubling a batch, but I have doubled and tripled batches before without a problem.
-You’ll find over time that the ripeness of the fruit has a lot to do with how the jam sets. While you are boiling up the fruit, dip in a spoon, then pull it out and let it cool to get a feeling how it is setting. If it starts to set up almost immediately at room temperature, you’re probably fine.
-Strawberries and blackberries are labors of love. You are picking them and cooking them during the hottest and most humid days of the year. I pick them, and put enough in freezer bags for individual batches. Then I make the jam in the winter when the house is cold and dry.
Hello again, where did you get your canning rig? Mine is starting to get old and worn out.
My local Meijer’s (which is a superstore like Walmart) had these starter kits.
You got a huuge enamelware pot, with the aluminum tray to keep it off the bottom, and the Ball Blue Book, and the tong thingies, and the flat thingy that smooshes out the airspots in veggies, and some jars, all together. I’m pretty sure it was this kit, although I didn’t pay that much, it must have been on sale.
If you’ve got freezer space, why not make freezer jam? You don’t need to sterilize the jars or cook the fruit. I like it better because the taste seems more like the real fruit.
I’ve only ever seen paraffin used for jams and jellies. Everything else, I can using the water bath method.
OK, so I just made my first batch of cooked jam. I used the stuff I had: enamel pot, regular metal tongs, no funnel. It was a little messy, but overall not too bad. Boy did the proto-jam taste good when we licked it off the pot after we poured it into the jars. Yum. The pot I had was the exact right size for the 8 8oz. jars I filled. All of the jars made that cool POP sound as I took them out of the processing bath, so we did that much right. Now it remains to be seen if the jam actually sets and tastes good.
In any case, it was a fun project and I hope the outcome is delicious jam to have even in the winter.
Awesome! I get a real charge out of canning – its amazing that with such simple tools you can store food for months. I put up dilly beans (dill pickled green beans) this weekend. The only challenge is not eating them as fast as I’m able to can them.
Half-set jam makes a nice topping for ice cream or pancakes. Waste not, want not!
Because we have enough humidity right now, and don’t want to boil gallons of water to add to it, we pick and wash the berries and spin them dry. (There’s nothing funner than a salad spinner!) Then freeze them to make jam in the fall. When you can open the windows.
How long does it take the jam to set? It’s been 12 hours and it’s still liquidy. At what point do I despair and bill it as ice cream topping instead of jam? I put one jar in the freezer because it didn’t fit in the processing bath, and that set up right nice and, well, it’s already been eaten. :o It was goooood. 
So either way it’s not the end of the world, but it’d be nice if it did set so I can give it as gifts and put it in the cupboard and stuff.
Unless it is uncommonly hot in your kitchen, it should be set by now if it is fully cooled. Sorry.
Never fear, people will appreciate gifts of blackberry ice cream topping!
I had some blueberry-lime jam that never set up, and all the people I gave a jar to begged for more. Begged, I tell you.
I had some problems with jams using pectin a few years ago. They refused to set properly. So I stopped using pectin and started making jam the way my great-grandmother did.
Measure equal volumes of sugar and fruit. Stir to combine. Put it over low heat and cook s l o o o w l y, stirring occasionally. The sugar will draw liquid out of the fruit as it melts, and you will at first have a somewhat thin mixture. Keep a candy thermometer in the batch as you cook and stir.
When the candy thermometer shows your bubbling jam to have reached 220 degrees F, you may take it off the heat and ladle it into jars and top with paraffin or process in a boiling water bath as usual.
The jam will set as it cools.
That’s the way I do peaches, UD. I stick to pectin with berries, though.
Regarding doubling batches, the only trouble is ensuring that the pectin is thoroughly mixed in. The more pectin, the harder to get a good distribution. As long as you keep that in mind, and make sure your pectin is fully and evenly incorporated, double and triple all you want.
I’ve had jam take up to a week to set, so procrastinate on that desperation.
If you wait, and it still doesn’t set, you’re not out of luck.
I’ll assume that you used pectin. Did you follow the proportions as recommended by the manufacturer? That’s usually where the failures occur, but I’ll assume that you did. Remember that the ripeness of the fruit can effect the setting of the jam.
You can open the jars, dump them in a pot and reboil them if you want to. You’ll have to rewash the jars, and get new dome lids. I’ve had to do this before. Try adding a little more pectin when you reprocess it.
Good luck,
plynck
OK, so all the jars have set now but one. Nothing else to do but eat that one right away. 
What a hardship. Next I think I’m going to try blueberries. Those are my favorites. I’ll have to buy them, but what the heck.
I’ve made plenty of blackberry jam with no added pectin and that way you don’t need as much sugar, it works fine. Even better if you throw in some underripe fruit. Some jams can take a few days to set up. If it never does set up you can just put it all back into the pot and cook it down some more, then re-can everything. If your jam turns out too hard you can melt it all back down and add some extra liquid, then re-can. Jam is very forgiving.
And tasty.