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How to make jam

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Dan Lepard Dan Lepard | 12:20 UK time, Tuesday, 9 August 2011

As a nation we’re very passionate jam makers and terribly polite eaters - not the best combination when you want to raise the bar in the preserving stakes. I dread to think how many tonnes of fragrant colourful fruit are turned into grim overcooked jam, murky looking and caramel flavoured, packed into jars that smell of last year’s pasta sauce.

Making excellent jam is really achievable at home, and very quick and easy when you get your head around some of the science behind it. Be warned, I’ll shake some of your habits and question some of the laws regarding jam making, but we’ll come out of it better.

Dan Lepard's jam


There are two women all wannabe jam pros must know about. Yes, women dominate in the jam-making world and I can’t see any men threatening that right now. First up is Pam Corbin, the founder of Thursday Cottage jams and the author of the River Cottage Preserving book. Pam writes with good sense and is someone I always trust in jam matters. The second guru is Christine Ferber, the queen of soft-set fragrant preserves (jam seems too coarse a word here). Her books are great for ideas about combining fruit and maintaining their delicate fragrances.

The best fruit for making firmly set jam is slightly under-ripe, not fully ripe. The setting chemical pectin as a substance that decays as the fruit ripens, even in fruit traditionally rich in it. Under-ripe fruit has the most pectin, but less fragrance and a subtler flavour. You can use fully ripe fruit, but be prepared for the set to be very soft or for there to be no set. The possible set of the jam is primarily determined by three things: the pectin, the sugar level and the acidity:

  • Pectin: has a good list of the fruits that are high or low in pectin. If you’re unsure, assume your fruit is low in pectin and will need some help.
  • Sugar: you want enough sugar to give a good set without masking the natural sweetness of the fruit. As the liquid evaporates the percentage of sugar in your jam gets higher, so make sure your cooked fruit contains very little liquid when you add the sugar in order to keep the boiling time short.
  • Acidity: adding lemon juice activates the pectin set. Even when fruits are tart and pectin-rich, like blackcurrants and gooseberries, lemon juice or citric acid is often needed to create the set. It’s usually added with the sugar or later - not when the fruit is first cooked as this will firm the skins and give a coarse texture.

Don’t be afraid to add pectin if your fruit needs it. Though pectin is a chemical, not all additives are unnatural. The pectin we buy is usually extracted from apples or limes, and it will help you keep the cooking time short which helps the colour stay bright and the flavour clean and sharp. There are other ways to add pectin. I use Pam Corbin’s tip of grating Bramley apple in with the fruit for a firm set, or pear for a softer set.

Most fruit needs to be cooked once before the bulk of the sugar is added to soften the skins and extract the pectin for a smooth set jam. Even strawberries benefit from slight cooking first. However, some jam makers like Christine Ferber and Sophie Grigson encourage soaking the fruit overnight with some of the sugar so that it releases liquid. This syrup is then precooked. This method is really good for extracting subtle flavours from the fruit and keeping the skins slightly firmer to retain their texture.

Cook the fruit in just enough water so that when the skin or peel is soft there is only a little liquid remaining. This will help your jam to cook quickly to a set, preserving the colour and flavour. Finally, to skim or not to skim? That is the question! I only skim my jam at the end if there is a lot of white foam left, but usually I don’t.

I’ve written a special small batch of jam recipes for BBC Food, combining some of my favourite flavours. Experiment with these and do swap ingredients to your taste. And let us know your tips, or anything you want to question me on.

Dan Lepard is a food writer for the Guardian and a baking expert.


  • Comment number 1.

    This is really useful. I've tried making jams a few times and it's good to see things explained.

    Also, it's good to see recognition that "not all additives are unnatural".

  • Comment number 2.

    This comment was removed because the moderators found it broke the house rules. Explain.

  • Comment number 3.

    Hi Dan
    Nice article
    Just want to draw your attention to a discussion you triggered on high-pectin low-sugar jams, German style, you might find it interesting.

  • Comment number 4.

    Hi Sue,
    Just read it, and yes you could make a similar mix yourself. Rather than going full-on pectin or totally without, you could use half pectin sugar and half regular, or one-third pectin sugar and two-thirds regular, according to how strong you want the effect to be. We sometimes add a smidgeon of pectin to pickle to make the set a little more gloopy and less runny.

    And again, I must stress that we shouldn't think pectin is an artificial ingredient - if that worries you - as the stuff you buy is usually made from lime skins or apples. In food and nutrition, think of pectin as "a good guy".


  • Comment number 5.

    Thanks Dan

    As a former biochemist I am quite happy with pectin :)

    I remember extracting it as a practical exercise when in the 6th form, doing the Food Science option for Chemistry A-level! It looked a bit like a ball of silicone - think we overdid something a bit. It was certainly easy enough for schoolgirls to do, very simple & no nasty chemicals as I recall .

  • Comment number 6.

    Can I use Honey instead of sugar ? Thinking of raspberry Jam.

  • Comment number 7.

    Hi Flatt1e,
    I'm sure you can and a quick google:

    shows lots of ideas. But...have never made it myself to be honest. My only thought is that honey can be quite a strong flavour and raspberries - though bright and sharp - have subtle flavours that might be masked by the honey. I'm not sure there's a health benefit, especially with the boiling.

    Do let us know how you get on.

  • Comment number 8.

    I came across this article through a twitter link and I am so glad I found it. My children and I have picked many kilos of fruit at a local PYO farm and having made lots of crumbles, tarts and ice cream we are now also inspired to try out some of your jam recipes - early christmas present making weekend coming up me thinks!

  • Comment number 9.

    I am inspired. Blackberry and apple season is upon us and I shall try to improve my jam making habits for the better. Dont forget the presentation - there are some really nice jars to be found.

  • Comment number 10.

    Great blog post on jam. I've just uploaded this video on how to make plum jam. Hope you like it.

  • Comment number 11.

    Nice blog, Dan - I missed it when it was posted last month. I like the idea of peach and maple syrup jam. I've some peaches that are yet to ripen and I'm not sure they will make good (ie, attractive) eating peaches now so I might make a batch using those.

  • Comment number 12.

    Hi Dan

    Very useful article, many thanks, jam making a big passion for me and have been doing lots of unusual jam with great results. A quick question, am finding the blackberries around here are very seedy, making a very fragrant and lovely tasting jam but it is very 'crunchy' - any tips?

    Many thanks


  • Comment number 13.

    Hi Dan,

    I'm not a jam maker, but I cam across your article trying to find an explanation for why jams only seem to come in pure flavours. Why aren't jams made of blended fruits?



  • Comment number 14.

    Hi Alex,

    In commercial jam making, it’s a combination of things. Here in the UK the trading standards people have very strict old-fashioned rules about what is and isn’t jam - for example, my recipes here using apple wouldn’t be allowed to be sold by some authorities as apple is considered an adulterant in jam making - and insist on jam being made with pure fruit.

    So though a “blackberry and apple” jam is a lovely idea, commercially many authorities wouldn’t allow it to be sold as “jam” in the UK, though it could be called a “high-fruit spread”.

    Then I think there is a fear that shoppers in the UK would be uncertain by combined-flavour jams, say “blackcurrant and plum”, and this fear would affect the buyers for the supermarkets who effectively decide what will and wont be on the supermarket shelves.

    It is always worth writing to supermarkets and companies, and telling them what products you’d like to see. It doesn’t always affect what they sell, but sometimes they’ll read a letter and that will start a change happening.


  • Comment number 15.

    Hi Caz,

    For seedy fruit like blackberries, raspberries, red and black currants, the only option other than diluting it with a soft fruit like plum or apple is to sieve out half of the seeds after cooking (before the sugar is added) making sure you press the seeds well against the sieve with the back of a spoon to extract any juice surrounding them. I don’t personally like seedless berry jam - a bit unnatural - but removing some of the seeds makes it much more pleasant to eat.



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