Image for blog - How to Make Jam with Rosie Jameson Image for blog - How to Make Jam with Rosie Jameson
Features // Blog

How to Make Jam with Rosie Jameson

Publisher - Great British Food Awards
published by

Dani R

Jul 13, 2021
15 minutes to read

Each month, master preserver Rosie Jameson, founder of the Guild of Jam and Preserve Makers shares her seasonal preserving tips to help you make the most of great British produce

Well, the holidays are here and hopefully the summer is ahead of us, with time to make some more memories. The summers that you remember as a child somehow never involve rain. They seemed hot, with scratchy dry grass making your legs itch when playing endless games of cricket in the garden. Going on holidays with aunts, uncles and cousins, always someone to play with on the beach. Simple fun but there it is, all locked away in my memory.

Some of my earliest memories involve jam making. My mother had to preserve fruit by bottling or making jams. She didn’t particularly enjoy doing it but needs must. There was little refrigeration and certainly no home freezing so there was endless picking, topping and tailing and boiling to be done.

I, on the other hand, loved it!

From being sent into the blackcurrant bushes to pick the low-hanging fruit that the birds had missed, to stringing, topping and tailing gooseberries - I thought it was fun. When it came to making the jam I ‘helped’ by having a little stool as a table with the tools of my trade laid out - wax discs, cellophane covers, rubber bands - and a saucer of water to dip the cellophane in; just lightly, mind. Handed up to Mum, in the right order, I was only 4 or 5 and couldn’t see over the table! Later, laying in my little bed, the soundtrack of my childhood summers was the concert on the radio and the cellophane covers drying and ‘pinging’ as they did so.

You can make your own traditional memories in the holidays: pick or buy some lovely fruit and make some delicious jam for tea. Get children involved. Make a few scones, have a picnic tea even if it is just an adventure at the bottom of the garden. If you live by the coast, a beach picnic cannot be beaten.

Children will never forget their first taste of real jam; it is indescribably fresh tasting and bursting with flavour. Spread out a blanket, unpack the picnic, make daisy chains, check ‘who likes butter’ with the buttercups that have sprung up in the flower beds. Play noughts and crosses with stones and shells. Happy days.

Nostalgia – it’s a powerful drug.

My whole life now is Preserving, preserving - I would like as many people as possible to be drawn to making their own food and to understand that this does not involve hours and hours of solitude in a hot and steaming kitchen, weeping over large vats of jam and chutney.

The variety of preserved food is enormous and can enrich your everyday eating in ways that are impossible to explain in a few words. Fundamentally though, you will always get more out of a jar of home-preserved food than you put into it. When you pop that lid, memories of where you got the fruit or vegetables from (the garden, the farm, a friend), the day that you preserved it, friends you have gifted some to and your exasperation when they kept coming back for more and not returning your jars - this is called nourishment. This is why food you have had some interaction with is more satisfying, more tasty, and more memorable than food that is mass produced. Food manufacturers may be able to mimic with their chemical concoctions but they can never feed your soul.

So, let's make some jam...

Jam is more of chemistry lesson than cooking. You need four elements in the right combination for success.

You need fruit with sufficient pectin - like raspberries, currants, plums. You can make jam with low pectin fruit such as cherries, rhubarb, blueberries but you will probably have to add pectin to achieve a set. Modern strawberries fall somewhere between the two camps.

You need acid and if you are a beginner I would suggest you add the juice of one lemon per 1 kg of fruit.

You need sugar - the right amount - which is equal weight of sugar to fruit.

Finally, you need heat, enough heat for the sugar, pectin and acid to react together to achieve the set. Only add enough fruit to your pan so that it is about one third full. You will then have enough room for the rolling boil without the contents boiling over.

Rosie's Easy Raspberry Jam Recipe

Image for blog - How to Make Jam with Rosie Jameson

​Rosie’s raspberry jam recipe relies on just three ingredients - 900g of raspberries, 900g of sugar and the juice of one large lemon. Bring it to a rolling boil and wait for the magic to happen!

Read full raspberry jam recipe here

How to know when your jam is set and other top tips

Before starting to cook, make sure you have enough jars and lids!!

Place two small plates or saucers into the fridge or ice-making compartment if you have one. Wash jars and place in oven at 100 degrees C to dry and sterilise.


When you add the sugar, stir in off the heat to prevent sticking to the hot pan.


Place back onto the heat, turn it up higher and bring the contents of the pan up to the boil, then reduce to a ‘rolling boil’, (Just high enough so that the jam doesn’t boil over). Stir once or twice to prevent sticking, but each time you stir the jam it will cool slightly so don’t overdo it.


When the jam has darkened and thickened slightly, usually after 6 mins or so, you can test for a set. Place a small amount, around a teaspoonful, onto one of the cold plates, place back in the fridge for a few moments. To test, gently push the edge of the jam on the plate to see if it ‘crinkles’ - if so, the jam is ready.

If it is not yet ready, continue to cook for a further 4 mins, then try again. If still not set, add the juice of a further lemon and try again but after that, jar up anyway and use as soon as


If there is sugar foam on the surface of the jam this can be dispersed by stirring quickly or by stirring in a knob of butter (if the jam is for home use.)

There is no need to remove and bin it unless there is so much that it can’t be stirred in. This sometimes happens with some strawberry jams and plum jams.


With whole fruit jam or with marmalades, leave to stand for at least 20 mins as if you
jar it too hot all of the fruit will rise to the top of the jar. This is not necessary with fruits like raspberries and blackcurrants.

Remove the jars from the oven. If possible, use a jam funnel to fill the jars - it will save work and waste.


Ladle the jam into the jars right to the top of the jar and then seal immediately with a new lid. No need for waxed discs unless you are using cellophane covers.

Leave to cool and set. The jam will keep, in a cool, dark place for several years - there is no need to refrigerate either open or unopened.

Some final tips

Image for blog - How to Make Jam with Rosie Jameson

Don’t worry if your homemade jam does not look like the jam you buy in a supermarket - your jam is made with a higher level of fruit and without artificial setting agents. If it is too runny, use it on porridge or ice-cream - or just lick your fingers a lot!

If it is too solid it means that instead of cooking to a set you have cooked it too long and evaporated too much of the natural liquid from the fruit. You can still use it though - if you can get it out of the jar. Just slice it and use on porridge or in jam tarts. The only time you would need to throw the jam away is if you have burnt it in the pan - nothing disguises the taste, so best dispose of it quickly and don’t waste your jars on it.

Rosie runs online preserving classes throughout the year and offers monthly preserving boxes and jam and preserve making equipment. Visit for more information.

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