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. mauramac

    Can I add my name to list of thermometer owners who do battle with it every time 🙁 I bought one because I stupidly thought it would take all of the guess work out of getting jam to setting point.It never goes above 100c no matter what I am boiling. It appears to be well made and is by KitchenCraft. Its a stainless steel construction and the markings definitely wouldn’t come off but despite all of that it doesn’t do its job for my liking. It has a Jam marking on it at 103c and goes right up to 220c for chips. It does have a clip on the back and washes up really well – I just wish I could get it up to the jam setting.
    However – I didn’t calibrate it – didn’t know you had to but was told to put it in pan right from start so that it warmed up gradually. Never put it in boiling jam from cold. My maslin pan is my favourite purchase – I can never get over how easily it cleans up – no matter how thick or sticky the jam or jelly or chutney it gleams beautifully with just a quick wash in soap and hot water.I would recommend a maslin pan to everyone. I also use it to make up big batches of soup and stock.

  2. Until recently I too used to wait for what seemed like hours for the ‘set’ …
    Then one of my friends who had not made jam before presented me with a bottle of homemade jelly and said ‘ I boiled this for 4 minutes’ !!!
    It had a perfect set..
    She said look on the packet of jam sugar and it says to boil for 4mins / it does!!
    Since then I’ve had no trouble at all it works every time, even with my homemade pectin!!!
    It obviously pays to read the instructions….

  3. I’ve just made a batch of jam from your Apple & Blackberry recipe and I am so glad I read this article first. I’m a fairly inexperienced jam maker and so far all my jam has been tasty…but you kind of have to slice it rather than spread it!

    So I used my digital thermometer but then kept an eye when it got to 102? and it was definitely already setting.

  4. Louise

    I’ve become used to maslin pan, but I’ve always simply called it a preserving pan.

  5. judith kerby

    So pleased to hear that it isn’t just me having trouble with a new thermomoter. Picked about 40 lbs of blackberries last Autumn and could NEVER get the thermometer to read over 102 degrees. Gave up and used the wrinkle test.
    Just might experiment with calibrating thermometer with boiling water though.

  6. Can anyone direct me towards a thermometer which has an etched scale? I’ve lost the markings on 2 thermometers which just have a printed scale. I need to put the thermometer some way into the Maslin pan I’m using. That’s what I thought the clip on these thermometers was for.

  7. Great recipes and info about thermometers.I bought one last year after many years of managing without,and keep forgetting to use it!
    I tend to use plates and the wrinkle test,bonus like Magic Cochin says.
    Love my enormous’jam pan’which I bought a long time ago in a jumble sale for £5,along with a Kenwood chef-bit more expensive at £10.

  8. Hi, I usually use a digital themometer and aim for a temperature of about 104.5C, but even this precise figure leads to a lot of variation in set. Raspberries, blackberries all fine at 104.4, but overrip greengages are like stiff treacle. I made some Clementine Marmalade the other day and it set at 102.5C. Good job I noticed a glooping noise otherwise it would have been overdone

  9. okay, i think you’ve just sold me a maslin pan! i’m brand new to jamming too and just tried out the chilled saucer test today. i hope it worked!

  10. Hi There, I sumbled over this site looking for jam thermometer, I am convinced now that I dont need one, but certain that I need a Maslin! Must see a price for them and see if I will get the benefit. I have just started Jam making as my son gave me a glut of plums from his tree. Good site it’s very informative.
    Cheers Anne

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