My jelly boiled over

Cafe Society
1

I picked a giant pot of red currants a week ago last Friday. Turned them into juice last weekend. I got nearly two quarts of juice, more than ever before. Friday evening i finally made jelly, following the recipe in the Joy of Cooking. I cooked a quart at a time. The first quart boiled over and made a huge mess. The second didn’t. Details in the spoiler, because they are long.

the rest of the story

That is, per the recipe, i cooked no more than 4 cups of juice in a batch, used 3 cups of sugar to 4 cups of juice, relied on the natural pectin in the currants, and boiled the stuff until it reached 219F before bottling it. (The recipe actually called for heating to 220F, local boiling plus 8 degrees, but i did that last time and thought the jelly turned out a little too stiff.)

But, in the first batch, i missed a step. The recipe said, “bring the juice to a boil. Boil for 5 minutes while skimming the scum off the surface, then add the sugar”.

I added the sugar first, then the juice, then heated it.

And as i heated it, i noticed some scum forming, so i started to skim it off. As i did so, the liquid rather suddenly erupted into a mass of bubbles and overflowed the pot, leaving an enormous mess on my stove.

I turned off the heat, poured half the remaining sweetened juice into a second pot, and finished cooking it in two batches.

Then i cleaned up (i used some leftover bread as a sponge to mop jelly off the stove. It was delicious, at least.)

And then i confronted the other quart of juice. I decided to gamble on doing it all in one batch, in the same pot, but follow the recipe. So i brought it to a boil, skimmed the scum, and then stirred in the sugar and brought it back to a boil. I stirred constantly. And it boiled up a little, but never exploded, and crucially, never exceeded the pot.

So, i ask: did the first batch overflow because

  1. of the scum, which maybe created a lot of surfaces for bubbles to form or something?
  2. i stopped stirring it to skim the surface, allowing the bottom to heat past some critical point?
  3. of something else? (What?)

P.s. both batches taste delicious, and I can’t tell a difference between them.

2

Based on my own canning experiences, I’d say it was Option #2. I’ve noticed if I leave jams or jellies on the boil without stirring, even for just a moment, it’s enough to cause those sorts of disruptions. I couldn’t explain the physics of why, though.

I don’t can jams or jellies without stirring constantly. I’ve never worried much about scum, but I do skim it if it forms enough of it. While simultaneously stirring best I can.

I’ve found 220F is the right temperature, but they do mean only just. Hit 220F and it is done.

(Unbeknownst to me, I once used a thermometer that was broken. It stopped rising at 217F. I boiled and boiled, finally figured out the problem. You could have used that blackberry jam as brick mortar.)

One trick I’ve learned to ensure the sugar dissolves well is to blend the juice or berries with the sugar the night before. Cover and allow to sit overnight before carrying on with next steps.

Wish I had been nearby with some leftover bread, too. :slight_smile: It sounds lovely!

3

I cooked it beyond the first time the thermometer registered 219, and until it was wobbling between 218 and 219. It hadn’t touched 220. I’m very happy with the texture. The stuff i made last year i cooked until it mostly said 220, and that came out stiffer than I’d like. Maybe “first touch of 220” would be perfect.

Other than that there’s still a tiny bit of char under the gas regulator in the burner (that i couldn’t scrub off), I’m quite happy with this year’s jelly. Great taste, easy to remove from the bottle with a knife, easy to spread on my toast, gorgeous color.

4

I’ve never made jelly, but my grandmothers always did, and they always used a pot that was bigger than one they thought they would need.

5

The juice plus the sugar filled comfortably less that half the volume of the pot. And it’s easier to measure the temp if it’s at least an inch and a half deep.

The stuff just exploded into an enormous mass of bubbles, many times the liquid volume.

But maybe a slightly larger pot would be safer.

6

Probably my most exciting canning mishap occurred when I was lifting jars of canned tomatoes out of the water bath. It was barely off the boil and a jar exploded. Fortunately, I was holding it in a lifting device with the bottom pointed away from me. But damn, what a mess!

Now I let the jars cool briefly while still in the water bath before removal.

I do think the perfect temperature for jellies and jams is highly kitchen-dependent. Once you learn the correct one for yours, don’t mess with it!

7

I make maple syrup, and the bubbly boilover once it’s just getting to ideal temp/consistency is a problem with syruping, too. I too have made sure to use a bigger pot, even though it’s harder to monitor the temperature. I found the right larger pot and better thermometer and that helped. And it’s stir stir stir, and if I need to stop stirring I lift it off the heat. Boilovers bite.