Easy Rhubarb Jam Recipe (2024)

FAQs

What is the secret to making jam? ›

The Magic of Macerating

One of my favorite tricks for jam-making is macerating the fruit first. Macerating is the process of coating the fruit in sugar and letting it rest for a few hours or overnight, which pulls some of the juice out of the fruit and creates a syrup with the sugar.

Over-ripe or damaged fruit is not ideal - the jam will not set well and is likely to deteriorate rapidly. The amount of sugar you need to make jam depends on the amount of pectin in your chosen fruit, but generally the fruit-to-sugar ratio for traditional jams is 1:1 (ie. 450g/1lb sugar to 450g/1lb fruit).

Instead, this recipe for jam is thickened by removing the fruit from the collected juices while cooking. Once removed, the remaining juices are cooked until they reach 221°F. At that temperature, the added sugar and the fruit juice thicken up to the perfect consistency. No boxed pectin needed!

Lemon is crucial to balancing those sweet flavors, but it also helps the pectin to firm up the jam. It can be added at the start of the cooking process or towards the end, but what must be taken into account is that adding liquids to the jam mixture will inevitably require the jam to cook for longer.

I prefer to make jam using normal granulated sugar or caster sugar. However, you can also use sugar with pectin added (also called “jam sugar“), and I find this sugar is most useful when you are making jam with fruit which contain low amounts of natural pectin.

Once the jam reaches a slow, thick boil, add lemon juice and continue to cook, stirring constantly until the jam returns to its earlier consistency, about another 5 minutes.

5. Do Not Stir Once Mixture Is Boiling. Once your jam/marmalade it has reached a rapid rolling boil do not stir it. Stirring it will alter the temperature of the jam/marmalade meaning it will take longer to reach the setting point.

Some people use it to good effect, but I tend to avoid it because I have gotten much better results by just using pectin-rich fruit that is just ripe enough, and then dialing in on the sugar and acid and heat. Jams that I've made with added pectin have often turned out too thick and rubbery, with a dull flavor.

If you simply take fruit and cook it with some sugar to sweeten it a little, it will get thick enough to turn into jam by the naturally occurring pectin in the fruit and the process of reduction. Reduction occurs when we simmer the fruit, and the liquid turns to steam and evaporates, which thickens the jam.

For every two cups of fruit puree, add to the pot one scant cup of sugar and 1 tablespoon freshly squeezed lemon juice. Stir to combine, and taste. Very tart fruit (such as sour cherries or some plums) might need a little more sugar. Very sweet fruit (such as white peaches) might need a little more lemon juice.

How many cups are in 2 pounds of rhubarb? ›

A cup is a measure of volume while pounds is a measure of weight so a direct calculation is difficult. If we only take liquid weight into account, one cup is eight ounces and two pounds would be 32 ounces so two pounds of rhubarb would equate to 4 cups.

Pectin Substitute

Cornstarch - Another plant-based thickening agent, cornstarch is a great substitute for pectin. Gelatin - For non-vegan menu items, you can substitute gelatin for pectin, but it will yield a different consistency.

It's Not Only About Pectin

There's another reason why lemon juice is added to most jam recipes: for safe canning and to prevent the growth of bacteria. Bringing the pH level down means jars can be sealed in a regular boiling water bath in a reasonable amount of time (sometimes as little as 10 minutes).

Generally, it's advised to add one tablespoon of lemon juice per pound of fruit. However, if you follow the jam recipe closely, you may wish to use bottled lemon juice. Bottled lemon juice has a standardized level of acidity, so there'll be no question whether you've added enough.

Cook it again.

Wash and sterilize the jars and try again. While you can simply reduce the jam to your liking, you can also add commercial pectin or chia seeds to the reducing jam to guarantee thickening.

Add pectin.

Whisk a tablespoon of powdered pectin (preferably the no-sugar-needed variety) into the pot of cooking jam. Test for thickness and add another tablespoon if needed. Learn More About Pectin: What's the Deal with Pectin?

By adding pectin near the beginning of the cooking process, the fruit mixture will thicken to the ideal consistently nearly immediately, allowing you to fill many more jars of jam than you would without pectin.