Jam raspberry

How to make the best jam at home

Jam expert Thane Prince shares her best tips for making those summer fruits last all year round

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How to make the best jam at home

Making jam is a brilliant way to make the most of those sweet summer fruits while they’re still around, giving you a taste of seasonal sunshine even in the depths of winter.

We chatted to Thane Prince, cookery writer, jam expert and author of Perfect Preserves — a beginner’s guide to chutneys, curds and other preserves — about how to make perfect jam at home every time.

From common misconceptions to perfecting flavours and the ultimate jam-making technique, check out Thane’s ultimate top tips below.

Making jam isn’t tricky

“Jam making is very easy – we think of it as a time-consuming activity because our grannies used to dedicate days and days to making it in huge quantities. They had all the time in the world because they were home all day, so they filled the larder top-to-bottom.

“But you don’t need to sacrifice a whole day and fill every cupboard in the process; you can spend under an hour in the kitchen and end up with a few jars for you and your loved ones at the end of it. It’s not labour-intensive at all!”

You don’t need any special kit

“I never use a jam thermometer. I did when I started cooking jam and all I did was burn the jam. Instead, I recommend the old-fashioned saucer in the freezer technique. 

“First, put the fruit and the sugar in the pan and cook it over a very low heat until the sugar dissolves completely and you can’t see any grit on the back of your spoon. Once it’s dissolved, bring the mixture up to a full, rolling boil — this is why you need a big pan for jam making. 

“Bring up the temperature so it bubbles and bubbles and bubbles. At the beginning, you’ll notice that the bubbles are very frothy. After a while, the bubbles will turn sluggish (larger and stickier) as the jam cooks. Once you reach that stage, your jam is nearly ready to set. To double check, switch the heat off from under the pan, take a saucer out of the freezer, put a spoonful of jam on and once it’s cooled slightly, push the jam with the tip of your finger and if it wrinkles, you’re good to go!”

Learn the basics

“Making jam is all about getting three things in balance: enough acid, enough sugar and enough pectin in order for your jam to set. For every 500g of fruit, you need 500g of sugar — either jam sugar or regular sugar depending on the pectin content of the fruit you’re working with. 500g of fruit and 500g of sugar produces approximately enough jam for two jars — one for now and one for later.

“Your fruit should be as sour as lemon juice before you add the sugar in order to make sure you’ve got the acid levels right. The acid mixes with the pectin to help your jam set. If you don’t have enough acid, simply add a spoonful of distilled vinegar and that’ll do the job nicely. It’s very simple."

Jam sugar is your secret weapon

“If your fruit has a low level of pectin, like strawberries, blackcurrants or blackberries, use a jam sugar. Jam sugar is sugar that has pectin already in it. The pectin comes from either apples or citrus peel, so it’s perfectly natural. If you add that, you’re good to go! Equal amounts of fruit and sugar, perhaps a spoonful of vinegar and you’re there.

“Other fruits, like gooseberries and apples, contain lots of pectin and lots of acid, so you just need to add regular sugar. Apples also contain lots of pectin and are quite tart, so you could mix those with strawberries which have almost no pectin and do a lovely strawberry and apple jam which tastes delicious.”

There’s a formula for a reason

“People try and make low sugar jam, which is nigh-on impossible at home. If you want to eat less sugar, eat half the amount of jam! 

“There’s no point in making a low-sugar jam yourself. You can make any number of low sugar preserves that you have to keep in the fridge and are very sloppy and they’ll be fine, but if you want to make a proper jam, you need equal quantities of sugar and fruit.”

Get creative with what’s in season

“You can add all sorts of things to make your jam extra special; plum and cardamom is delicious. Crush some cardamom seeds and pop them in with plums. Gooseberry and elderflower - either blossoms or cordial - tastes delicious and is great because gooseberries and elderflowers come out at the same time. Apple and cinnamon is an obvious one. If you think of a flavour that you like, then you can probably find a way of making it into jam.

“You can put spirits into jam too. Add a little towards the end once the jam’s done cooking. It’s a great way to add a little twist.”

Keep it fresh

“Sterilising jars is something that lots of people worry about but it’s actually very simple. I just put them in the oven or the dishwasher. 

“The dishwasher method is the easiest; put them in and run them on a hot programme. But if they’re all already clean, then simply put them on a baking tray and put them in the oven at 200C for 20 minutes. 

“Putting the hot jam into the jars while they’re still hot helps you make sure they’re as clean as possible, helping your jam keep for longer in the cupboard. If you stick them in before you start to make the jam then you’re all ready to go!”

Summer flavours all year round

“I have jam at home that’s a couple of years old and is still perfectly fine. It tends to turn darker in colour after a while, which is why you should label your jam so you’re not spreading something on your toast without knowing what it is!

“Having said that, I don’t think you’ll find it will keep very long because if you make it in small batches, you’ll find that you eat it all up very quickly — who could resist?”

Have Thane's tips got you itching to get your jam pan out this summer? Make sure to stock up on everything you need, from jars to seasonal fruits, online or pop into your local store.