Home Recipes Preserving Tips: How to Thicken Jam

Preserving Tips: How to Thicken Jam

Preserving Tips: How to Thicken Jam

apricot jam and biscuitsCountdown to ecstasy…

The goal: Jam that drops from a spoon but stays on a biscuit (at least until I eat it, which is usually less than T minus ten seconds).

As a jam maker from way back, I never really embraced commercial pectin. This had more to do with my end results than any preconceived notion of its application. Sometimes I’d end up with jam that resembled a giant jello shooter or a gum drop in a votive. I would call it slicing jam or fruit gel in a jar. When I spied my homemade gifts of jam from 1998, and 1999, lining the shelf of a friend’s post-millennium pantry, I had to admit that the only thing denser than my jam was my denial of its shortcomings.

granny smith apples and sour cherriesTip One: With a decade of jam making under my ample belt, I’ve found the secret to thickening up runny low-pectin fruit jams: add an apple or two. Pectin is a naturally occurring thickener found in most fruits, though levels vary greatly. For example, apples are high pectin fruits, cherries low. vintage grater with applesWhen I make jam out of a low pectin fruit like sour cherries, I add a peeled, grated apple to the preserving pot to boost the thickness factor. Because the subtle flavor of the apple usually takes a back seat to the sour cherry, it’s a fruit marriage made in heaven where the strongest flavor wins. (No 50-50 here.) sour cherries ready for jamming

Tip Two: Another way to help thicken your jam is to put the undercooked fruit jam in a fine mesh sieve and drain the liquid. Return the liquid to the preserving pot, simmer until syrup thick then add the cooked fruit mixture back, stir and bottle up.

Here’s a list of low and high pectin fruits:

High Pectin Fruits

  • Apples (tart, under-ripe have more pectin)
  • Blackberries (also more pectin if slightly under-ripe)
  • Crabapples
  • Cranberries
  • Currants
  • Gooseberries
  • Grapes (Eastern Concord)
  • Lemons
  • Loganberries
  • Plums
  • Quinces

Low Pectin Fruits

  • Apples (overripe)
  • Chokecherries
  • Elderberries
  • Grapefruit
  • Oranges
  • Sweet and Sour Cherries
  • Apricots
  • Blueberries
  • Figs
  • Peaches
  • Pears
  • Plums (Italian)
  • Raspberries
  • Strawberries

Happy jam making, and remember this:  if it takes a few tries (from someone who’s been there), a runny jam is merely a reason to make an ice cream sundae.Now you see it…

…now you don’t.


  1. That ice-cream sundae looked so good!
    I’ve had my share of fruit sauces and toffees 🙂
    My new favourite toy is the sugar thermometer I bought last year – no more guess work as to setting point.
    But the apple trick is a great idea! XO

  2. Good point Janet, Is that a Celsius thermometer? And tell me what is the jellying point in Celsius? 😉 I may break down and buy a new thermometer as the old hit the floor last month after I failed to see one of two sleeping dogs.

    • Tom, beautiful website you’ve created. Thank you for the jam-thickening advice. Cherry season here in Australia and 10 kilograms were used to make jam on Friday evening; my first attempt. Wonderful colour in the fruit but there’s a difficulty in its setting. Apples as setting-agents are out if season (unless you want chainstore-coldstore stale sponge-soft apples at this time of the year, which I don’t), but I have some fresh red currants to hand (it’s an upside-down world!) so will attempt to remake this afternoon… gently.

      • Hi Jamie, I think your solution of currants is brilliant, as they are high pectin fruits. I’ve also heard citrus rinds are good pectin producers but I’ve not tried them myself. Enjoy your gorgeous summer. As a Northern Hemisphere kind of guy, I’ll try not to be too jealous.

  3. Thanks Tom….great tips always. My Discovery apples are mostly picked….and the best looking crop ever. If you’d like any let me know – they are on the tart side.

  4. Good tips-I’ll use them this weekend for strawberry and blackberry preserves. Any tips on how to keep your berries whole? Add some at the last minute to keep them from mushing?

  5. Every time I read one of your posts I marvel at: your writing skills, your cooking skills, your inspiration skills. I’m inspired to try your suggestions, but I think it would be easier to just show up at your door and beg.

  6. Great idea Tom! I don’t really like to use pectin either. Recently I made Apricot Peach jam without pectin – it turned out great….would love to get my hands on some sour cherries!

  7. Sheryl, apples, did you say apples, oh yeah I’ll be over once I think of an appropriate barter item 😉

    Gail, I think you have a fine idea, begging works, especially after you’ve coughed $18 for the ferry ride over.

    Ina, apricot jam, it doesn’t get any better, as for sour cherries, they tend to be smaller trees, got room?

  8. Hello Tom, I just recently started getting your Tomagrams and I am enjoying them enormously. I find a great deal of inspiration in your choice to lead a lifestyle in which you “follow your bliss,” as Joseph Campbell suggested to us all…and also in the way you share it with us through your witty words, luscious photographs, and generous tips. Thank you so much! Looking forward to many more…

  9. Hi Tom – my thermometer is in both Celsius and Farenheit – setting point for Celsius is 105 – 106c (220 – 222F).
    I understand about the sleeping dog thing – I nearly dropped a boiling pot of Crab Apple Jelly all over a cat who was sitting, unbeknownst to me, at my heels. I wouldn’t have minded about the jelly, but it surely would have damaged the cat!… and I imagine I would STILL be cleaning up sticky jelly surfaces lol

  10. Love your last comment. I do this, too. Thanks for listing the high and low pectin fruits. I’ll written then down for reference the next time I make a jam.

      • Sometimes turning off the heat and letting the jam sit and evaporate more, will do the trick. Let it completely cool, and reheat until simmering when ready to jar up.

  11. It’s funny though: blueberries and figs gel very easily for me! No need to add anything.

    If you like rhubarb, you could also add some rhubarb to helg gel, and you’ll have a mixed jam: peach rhubarb, strawberry rhubarb, cherry rhubarb…

  12. Just made my first jam last week. It was such great fun. We used pectin and its a tiny bit runny. Next time I make jam I will add some grated apple. Thanks for the inspiration I just discovered your site! Thanks!

  13. Testing Pectin Content.

    Cook fruit until soft, spoon 5ml/1 tbsp of juices into a jar add 15ml/1tbsp of methylated spirits (Called denatured alcohol in the USA) and shake! After 1 minute a clot should form.

    1 large clot means pectin content is high.

    2-3 small clots indicate medium pectin content and should achieve a set.

    Lots of small clots means you will need to add pectin.

    Here is the trick that should work.

    For medium pectin content, add 15ml lemon juice for every 450g/1lb of fruit

    Low pectin, add 75 -90ml/5-6 tbsp pectin stock for every 450g fruit.

    Pectin stock can be made using under ripe apples or you can cheat and buy pectin powder. :o)

  14. Sorry forgot to add..A couple of tips that may help some.

    Jams and marmalades reach setting point at 105C/220F Jellies and conserves at a degree lower. Make sure the thermometer doesn’t touch the base of your pot.

    Tom I found your site this morning and have enjoyed reading.. It looks like you have a wonderful lifestyle. I am an Australian living in North Dakota, I am slowly getting used to the short seasons here (And lack of fruit trees). Thanks so much!

  15. Go Julie go! These are great comments and tips and I really appreciate the detail. What a nice girl from Down Under doing in the great state of North Dakota?

  16. just made my first couple batches of jelly out of Quince, the first one was just quince it looked a little runny but in a couple days it thinkened up quite nicely. The next day I decided to make Pepper jelly using quince its been about 3 days and the jars have been store at room temperature and it still looks a little runny I tried not to use as much sugar since my last batch was a little too sweet, I used about 1/4 of sugar per cup of liquid, should I have used more sugar? quince is a high Pectin fruit so I did not use Pectin. I love the Deep red color of our jelly but its a bit runny. I am open to any suggestions as to how to fix this, or should I just wait a bit more.

    • Hi Arnie, I usually use a 3/4 c sugar to one cup fruit juice. If you simmer to 221 degrees F, it will usually jel nicely. If you use less sugar it just takes longer as the water in the juice has to evaporate to reach the point where the mixture will rise to reach 221. Good luck and I hope this helps. Tom

  17. Thank you that is very helpful, I did notice that I didnt get as much finished product when I used less sugar, I just noticed you live in washington Im from Eastern Washington(Yakima) , my dad planted some Quince trees last year and we just figured out they make really good jelly so this last weekend we made jellies all weekend and experimented a bit my father also plants very hot peppers so I want to learn how to make pepper jelly properly. thanks again

  18. Hi Tom, Lovely website! may I ask some advice? I’ve made a scotch bonnet and Birdseye chilli jam, and I’m trying to avoid making it any sweeter than it is; I’ve added Pectin but it’s still very runny- would re-boiling it with apples help get the setting point up without making it too sweet?
    Any advice appreciated, thank you!

    • Hi Tahlee, Thanks! Now about your jam, sounds delicious and really unique, and hot as fire, too! You could try a couple things. First, simmer the runny jam in a large pan, that is one that is shallow and wide. This will cause faster evaporation which should thicken it. You can shut off the heat and let it cool and see how it looks. If the consistency is still not quite right, just simmer again and let it cool; that usually does it. You could also grate a peeled apple like Granny Smith or Bramleys into the simmer jam, and let it dissolve and soften in the jam. It may add a wee bit of texture, but the other flavors will overpower any sweet apple taste. Good Luck!

  19. tom,love your site.tried my hand today at watermelon preserves from memory of what grandma use to make.could’nt get it to thicken up,but thanks to you I remember why granny put lemon’s in.I’m letting my mixture cool until tomorrow and will add a little more lemon and fruit and re-cook,slowly,until I get the consistancy I’m looking for.NO jello shots,LOL thanks again

  20. Thanks for your great tips on thickening up jam with out pectin. I am making High country wild cranberry jam and trying to make it like mother did for pancakes. It had pulp and was thickened to where it poured out of the jar but was not runny. Mine was too thin and runny.

  21. Hi Tom,
    I got my hands on a gallon and a half of black berries. I cheated and bought all they had at the Farmers Market in Uptown New Orleans across the street from the Mississippi River. I lost my favorite patch when they sold it and put in a subdivision. In July, I am going to take the berries to my mom’s house in Cajun country and make the jelly there using an old family berry pestle and sieve on a stand. I was looking up how to freeze berries to make jam when I ran across your berry freezing instructions for dummies. Love it, the apple as pectin hint, and your beautiful and charming site as well. Thanks for the posts.

    • Ro, thank you for the kind words. Sounds like a trip to make jelly at mom’s house is something special. My mom gave me my grandmother’s pestle and sieve on a stand, nothing quite like it for making great seedless preserves. You’ll have to let me know how the blackberry jam or jelly turned out. Himalayan blackberries are to the Pacific Northwest as Kudzu is to the South, but at least we can make pie and jam from our invasive interloper. 😉 Take care, Tom

  22. I need HELP HELP HELP. I made a batch of hot pepper jelly and it was runny , so I added more liquid pectin and it is still runny. I have about 6-8 cups of runny – wonderful tasting – hot pepper jelly, can I save this? HOW

    • Hi Lora, I don’t use commercial pectin just for that reason. It’s not a bad product but I just find I’m not very good at using it effectively, and I get better results for what I’m looking for by finely grating a Granny Smith apple or two into the mix. Apples are high in natural pectin but don’t drown out your intended star fruit, which in this case is pepper. So finely grate a couple apples, and mix them into your jelly and reheat until your simmering jelly produces a thick double drop off the test spoon. Good luck!

  23. For a quick and easy fix just mix up a teaspoon and a half of arrowroot powder into about a tablespoon of cold water and make a slurry. Mix it in to your jar of runny jam and heat on high in the microwave( without the lid, of course) for a minute or two till the jam starts to boil a little. Turn off the microwave and stir the jam for just about 5 seconds. Voila! Thick jam! Put in fridge overnight and once it cools it will be even thicker and the arrowroot will not affect the taste or texture!

    • Thank you Les, for this keen tip. I’ve never used arrowroot before so I will give it a try. Maybe you can teach this old dog, some new tricks. Thanks again!

  24. Would adding lemon peels help thicken muscadine grape jam? I have added more pectin,lemon juice and sugar….like tablespoons of each and that has not helped. It has sat all night and still liquid.

  25. Hi, Tom, after totally screwing up some blueberry-orange jam (long story…), I tried your tip of removing the solids and simmering down the liquid and it’s finally setting up! However, I see raspberries are also a low-pectin fruit and I had good luck with a simple, no-pectin raspberry jam recipe – just mashed fruit, sugar and lemon, brought to a rolling boil and then simmered for about a minute! Anyway, thanks for the tip – will have to try the apple trick next time.

  26. I suppose, although I’d probably work my way through all my homemade hot fudge first! 😉 BTW, my problem the first time around was not noticing that the recipe called for liquid pectin and I had dry. I added it at the end and apparently with dry, you have to add it to the fruit first, boil it, and then add the sugar, lemon, etc. I tried one recommendation I found online to firm it up and it didn’t work. Then I tried yours…

  27. Hi, I love your writing style!
    Do you suggest putting an apple in a fig preserve? It is often not thick enough when I make it. Sometimes it is but I don’t know why.
    Any suggestions for a fig jam would be great! Thanks!!

    • Hi Tamara, thank you!
      As for apples in fig preserves, no I haven’t done that yet as fig jam sets up pretty nicely for me. It may be my figs have more pectin in them. What I would suggest, is to remove the jam from heat if too thin a consistency and let it cool completely. Then heat again very slowly (as fig jams likes to scorch on the pan bottom) and reach a low simmer again. I’ve found that heating and cooling and reheating allows for a lot of evaporation and thus thickens the jam without a use of thickening additives. You may have to do a couple of times to reach desired jam thickness or viscosity. Good luck, hope this helps. Cheers, Tom

  28. Hi there

    Linda writing from Cape Town South Africa. Thank you soooooo much for that tip to grate a granny smith apple to thicken my jams!!!!! It works. Awesome. I’m not a fan of pectin. Tried using Mezena thickens jam but changes the colour. Thank you again. Take care.


    • Hi Linda, thanks for sharing your jam-thickening success story. I love that I can hear from a kind voice halfway around the world before my morning coffee. And from beautiful Cape town, no less! Well wishes!


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