The Cottage Smallholder

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What is the setting point for jam and jelly?

Jam thermometer and maslin pan for jam making

Maslin pan with thermometer on our busy hob

Earlier this summer I decided to use my jam thermometer to help me find the setting point of jam. To my delight I noticed that it was marked ‘JAM’ at 105°c/220°f.
“This is going to be so easy.” I thought. “No more trailing back and forth to the fridge waiting for a tardy batch to set.”

Danny had bought me a 9 litre Maslin pan and this was the day it was christened. Up until then I had been using a very large non stick saucepan. So I clipped the thermometer to the side of the pan and feeling like a pro started to boil the jam.

I waited and waited, watching the jam get thicker and more gloopy. All the signs indicated that the jam was setting – coating the spoon, a thick residue on the sides of the pan but I persisted – determined to believe that a temperature of  105°c would produce perfect and tasty jam. I did eventually lose a bit of faith in the thermometer. Perhaps the jam was hotter in the centre of the pan? I moved the thermometer about but the temperature remained the same.

When the jam eventually reached the magic JAM level I took the pan off the stove. I didn’t need to test for a set – it was like glue and all the fresh fruity taste had gone. In fact the jam stuck so hard to the thermometer that it rubbed off of most the markings for the lower temperatures.

I did a bit of research on the Internet and discovered that 105°c is generally seen to be the setting point for jam. What had gone wrong? I checked the reviews for the Tala jam thermometer but no mention was made of  temperature faults. The reviewers did point out that the temperature points on the thermometer could easily be wiped away. Next time I’ll invest in a thermometer with etched points. The jam went down the loo and took a few days to shift. Danny was a bit irritated.

So much so that I wanted to chuck the thermometer over the fence but luckily kept it as I’ve discovered that our jam thermometer is useful as an indication that a jam/jelly is nearing setting point. When the temperature reaches 102°c, I stop whatever I’m doing and hover by the pan testing for set every five minutes on a plate from the freezer. The set happens somewhere between 102°c – 103°c, usually after ten minutes or so. I’d love to hear the temperatures that you use to gauge the setting point for jam.

By the way I thoroughly recommend investing in a Maslin pan if you are keen on making preserves. Apart from the thermometer fiasco all my jams, jellies and chutneys have been much easier to make this year. Perhaps is just that the design of the pan – a larger surface area compared to the base. Even the “glue 105°c jam” didn’t burn the base. This combined with a Silicone Spatula means that not a drop of jam is wasted and washed away in the sink.

Up until now I thought that Maslin pans were an unnecessary expense. Like my attitude to the simple but efficient jam funnel I have been proved wrong, yet again. The latter is used constantly for putting rice/beans/lentils/whatever into jars. And when I make preserves so little is wasted that it paid for itself in no time. And now I wouldn’t give up my Maslin pan without a strenuous, elongated fight.

  Leave a reply


  1. I am another one who does not use a thermometer but prefer the saucer dance between cooker and fridge. So far usually manage to get a set. Also interested in the use of the name “Maslin” pan. Our local hardware shop in Bishop’s Stortford used to be called Maslins and I think they originate from there


  2. great blog, so insightful and up to date


  3. Magic Cochin

    Love the description of the jam solidifying on the thermometer – it made us laugh this morning.

    “Personally I don’t bother with a thermometer and prefer to wing it with cold saucers in the freezer and lots of wrinkle testing. In the end, I think experience and instinct take over – and you get to lick a lot of jam testers off the saucers.”

    Here Here! I’m with Mary on this.

    BTW is “Maslin Pan’ what I’m supposed to call my Jam Kettle? Or are they different in some way?


  4. I once read somewhere that a thermometer should be moved around in the pan to get a more accurate reading. I too had a problem with one of these thermometers – used it to make marmalade and lost all the painted figures! However, I returned the thermometer to the supplier and received a replacement. Now, while jam-making, I keep the thremometer in a jug of hot water and just use it to test for temperature from time to time. Of course, I still use the old saucer and finger test as well!

  5. I have the opposite problem, my jam doesn’t set at the jam setting point. Having said that I tend to do jam in the microwave now as it is easier with small batches and on the whole I can tell when it is ready by watching it.

  6. I am no expert on jam making, but- 222F is the temperature for which I aim. Small batches seem to be the way to go, and lemon juice definitely seems to help.

    Better luck next time!

  7. Personally I don’t bother with a thermometer and prefer to wing it with cold saucers in the freezer and lots of wrinkle testing. In the end, I think experience and instinct take over – and you get to lick a lot of jam testers off the saucers. Yummy!

  8. Tamar, it is not merely temperature. Jelly is the trickiest of sweet preserves, fruit butters and jams perhaps the easiest.

    One suggestion I have is to process smaller quantities of juice in each batch. Use no more than 4 to 6 cups at a time and it more quickly reaches the jell point that if you are boiling a couple of quarts in one go.

    A perfect jelly should be clear, firm, quiver when a spoonful is removed from the jar. It requires some acid (tart fruit and / or lemon juice) and adequate pectin (high in under-ripe fruit, citrus -especially the white portion under the zest, apple, and others.)

    Some jelly (berry, especially) may have a soft set when first bottled, then continue to firm up over the next couple of weeks.

    I do not use commercial pectin, carefully balance proportions of ripe to under-ripe, and even make my own pectin from summer’s immature apple thinnings or citrus. Commercial pectins ask us to use too much sugar for the quantity of fruit juice for my taste.

  9. Tamar@StarvingofftheLand

    Figures that the only constructive thing I had to say — that you can calibrate thermometers in boiling water — has already been said, which means that all that’s left for me is to confess my confusion.

    I recently made several batches of jelly, which almost reached 220 (after cooking for a good 40 minutes), but were probably a couple of degrees short. They set, but not super-firmly, and I was disappointed in the cooked taste.

    I was left with a sense that 220 is an important temperature, but I wish I knew how to get to it without cooking the beejeezus out of my fruit.

  10. Did you calibrate your thermometer by placing it in a pot of boiling water? It should register 100 degrees C / 212 degrees Fahrenheit.Thermometers can be off by a few degrees – or more.

    I keep a thermometer in my refrigerator (should stay at 38 to 42 degrees F.), and another in the freezer (should keep at 0 degrees F.) The adjustment dials don’t even give temperature guidelines, just a range of single digit cooler / warmer settings.

    I have yet another thermometer in the oven. Just because you turn the oven setting dial to a desired temperature doesn’t mean that that is the temperature it reaches.


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