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.

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  1. Lol I had exactly same thing happen to me’! I kept with it&was adamant it needed to be 105 but in the end after 20mins of boiling at 101/102 I gave in&poured it in the jars&low&behold it set. I was amazed as when poured into jars it was very liquidy! Still it set though,did take awhile mind but I too am curious whether jam can be set at lower temp as no matter what I did I just couldn’t get it to 105!
    Anyway I tried making it again yesterday decided not to use thermometer unless got really confused&it worked. I basically decided I would boil&when sticking to sides of the pan&had been boiling for 10minutes I’d take it off&my method worked no saucers no therometer need and its set already! Yay! Hope when you next try it works for you too!! X

  2. danielsmummy

    Ooooh, rosehip jelly, yum. I am another failed thermometer user- I always check out the spoon first, when it looks like it is about to set, get the saucers out of freezer. I found using the thermometer gave inconsistent results- sometimes jam would set really well, other times it would remain too soft… As for maslin pans, I bought one a couple of months ago ( you know, do I really need one when I have this lovely old pressure cooker pot that does the job…), and so wish I got it sooner!!!

  3. I agree that using a thermometer as a guide is the most useful application. Fruit is variable even within the same type, and different sorts seem to set at different temps. My trickiest endeavour used to be marmalade, until I realised that if I doubled the amount of lemon juice and just let it boil for at least 20 mins, I would be guaranteed a set.
    I also use the spoon test. Hold a wooden spoon above the pan (turn the heat off to avoid steam interfering). If the drops form a gel and elongate rather than drip into the pan, it’s done. I rarely do a saucer test now. Too much faffing. Though I did get a terrible set on rosehip jelly last week. Will have to reboil that one.

  4. Ali at Very Berry

    I’m another one who’s missing all the relevant numbers off a jam thermometer… I have a fabulous raspberry jam recipe that you just boil for 3 minutes and go hang the temp – works every time. Something to do with warming the sugar maybe. Have been wondering about buying a proper preserving pan for years now… It always seems like such a lot of money…
    Love your blog!

  5. Ali Edwards

    We’ve had great problems with our jam thermometer too, but towards the other end of the scale I.e. the temp shoots up to 105 from very early on in the process. In fact, we had an instance recently with some plum jam where it shot above 105 and we spent 10 minutes trying to lower it! In the end, as everyone else seems to, we use the temperature as a guide and instinct/saucer test/etc for the rest!

  6. I started using a thermometer this summer too; not as a firm rule to follow but as an additional implement to help me guesstimate the setting point. I also use plates and wrinkle tests too and just knowledge of the look and feel.
    I also invested in a maslin pan this summer too and would agree that jam cooks more quickly in it; however I have managed to burn stuff to the base!!

    Finally I have learnt that it is better to do several small batches than one large one; not only is it quicker overall, but is far easier to manage!

  7. I had a jolly good laugh about stopping up the loo with your first attempt. In this house it would have been smack bottom and drain rods!

  8. Magic Cochin

    Hi Julie

    Wasn’t the shop in Bishop’s Stortford Maslens with an ‘e’ rather than an ‘i’?

    After a ‘google’ I think that ‘maslin’ is something to do with the metal it’s made from.

    I’ve only come across the term in the past year and wondered when it replaced the term ‘jam kettle’


  9. I’m quite new to making preserves. This year I had a go at making strawberry jam and apple butter. I’d really like a thermometer but I think there’s something rather mysterious and adventurous about the old-fashioned tests. It’ll probably help me to become familiar with the reaction of the food too. In the future, when I’m a pro maybe I’ll use the thermometer! 😀

  10. I have also been wandering about the Maslin name and agree that they are great.

    Used my thermometer for some damsom jelly and some pear and crab apple jelly. Both have been done twice and are still far too runny but the taste is perfect so I don’t want to mess too much, although I do want some wobble to them. My thermometer and instinct don’t usually let me down like this. Please help.

    Thanks. Inge.

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