We be jammin

We did it! We made our first batch of jam from our very own plums!

Well, when I say "we," I really mean that it was Brian who did most of the actual work. I was more involved in the planning stages: finding a simple-looking recipe and locating canning jars and pectin at the store. But Brian handled the actual processing of the plums and the jars, while I read Ngaio Marsh to him. And it worked! Mostly.

The first snag we ran into was finding canning supplies at the store. The Shop-Rite in Edison carries canning jars, including the little half-pint ones we wanted, so we figured surely it would have pectin also. But it didn't, exactly. Instead, it had two canning products that contained pectin plus some other stuff: Sure Jell, a mixture of dextrose, citric acid, and pectin, and Certo, a liquid product that contains "water, fruit pectin, lactic acid and citric acid (assist gel), potassium citrate (controls acidity), sodium benzoate (preservative)." This was a problem, because our recipe did not call for Sure Jell or Certo; it called for straight-up pectin. We weren't which of these products would work better, or how much of it we'd need to substitute for the one tablespoon of pectin in the recipe. We ended up choosing the Sure Jell on the theory that it was closer to plain pectin, and figuring we'd check the directions on the package and work from there.

Well, when we looked inside the package, it had its own recipe for plum jam, which used one packet of the Sure Jell for about the same volume of plums we were using—but with a whole lot more sugar. Kenji Lopez-Alt's recipe called for a pound and a half of sugar (3 and 3/8 cups) to 4 pounds of plums; Sure Jell's recipe called for 8 cups, more than twice as much. It also didn't say anything about adding lemon juice for added acidity, perhaps because the citric acid in the Sure Jell was sufficient for the purpose. So we decided we'd try it with the smaller amount of sugar, the full packet of Sure-Jell, and no added lemon juice, and hope for the best.

So, with some trepidation, Brian set about preparing the jam. On Monday, he chopped up and macerated the plums and let them steep overnight with the sugar, as Lopez-Alt recommended; on Tuesday, he boiled eight of our new jars to sterilize them, then started cooking the plum mixture. We skipped the milling step, since the plums, after having sat all night in the sugar, were pretty much reduced to liquid already; in fact, they were probably a bit less chunky than we wanted, but that was most likely because Brian had cut them up into smaller pieces than the recipe recommended. Then he began carefully ladling out the jam into the jars, leaving about a quarter-inch of head room at the top of each. This was a ticklish process, and there was a little bit of spillage, but not too much. (Lopez-Alt says he finds a plastic deli container the best tool for scooping the jam from the pot into the jars, but I don't see how you're supposed to be able to sterilize something made of soft plastic, and what's the point of using sterile jars if you're transferring the jam in a non-sterile scoop?) He put on the lids, added the rings, and turned them until they were just finger-tight.

Then, with even more trepidation, he began the actual canning process. A quick test had shown us that canning the jars in our mini pressure cooker wouldn't work, because even these small jars were tall enough to reach the fill line; if he'd put a rack underneath them, they would have been over the line and wouldn't submerge completely. So instead, he put his homemade canning rack in our big stock pot, heated up the water, and began heating the jars. Since they were so small, he was actually able to fit all eight of them in at once. He cooked them at a full boil for ten minutes, as the Sure Jell insert instructed, and then carefully removed them with his rubber-band-wrapped tongs and set them aside to cool.

We then settled down to a game of Scrabble, and as we played, we occasionally heard the gentle pop of one of the canning jars sealing—something we'd never actually managed to achieve with the larger jars. And when we checked the fully cooled jars in the morning, we found that all eight lids were securely in place, with no give in them when pressed. Brian tested them more carefully that evening by tugging gently on each lid, and when they stayed sealed, he put the rings back on and stowed them away in the basement. (The recipe says it's better to store them with the rings off, so you can see if one of the jars has lost its seal, but we didn't want to risk dislodging a lid by accident. We figure we can always check the lids again before opening them.)

There was one thing about our first batch of homemade jam that Brian found a little disconcerting; it didn't seem to have set up very well. When he tilted the jars, he could see the jam sloshing slightly inside, instead of staying put the way preserves from the store do. This is most likely because our recipe contained so little sugar. Lopez-Alt actually notes in his recipe that, since sugar aids jelling, it's best to add "a secondary jelling agent that works even without sugar," such as calcium; he recommended Pomona's Universal Pectin, which comes with a separate packet of calcium that you can mix with water and stir in when you cook the plums. But we couldn't get that stuff, so we had to work with what we had. As it turns out, the jam seems to have set up a bit more in the past few days, so now it only sort of oozes slowly when you tilt the jar. No big deal; it'll just make the jam easier to spread.

So, all in all, I would have to say this was our first successful attempt at canning. We're still going to try to eat as many of our plums as possible in their fresh, natural state, but if they're starting to go off faster than we can eat them, we'll be able to make another batch of jam with more confidence than the first. (Brian even unearthed an old packet of pectin that was hidden in the back of the pantry, so maybe next time we'll try that and see if it works better.)