Jam Making Basics: – The Role of Sugar

Learn how to make jam successfully – by understanding why sugar is integral to soft spreads.

homemade port wine plum butter

Although it seems that late spring is a long way off (as I write the east coast is getting walloped with snow and the Plains are expecting a blizzard), the early berries and fruits will be ripe soon, and ready to turn into jam.

Making jam is a fairly simple project, but there are a few basic requirements. Just like you can’t (usually) make a big loaf of bread without flour, water, and yeast; you can’t (usually) make jam without pectin, sugar, and acid.

You can learn all about pectin in this earlier post – What is Pectin? – but today we focus on sugar.

How Much Sugar Do I Need to Make Jam?

In general, long cook jams require less sugar than quick cooking jams.

  • A long cook jam is a combination of fruit, sugar, and acid, cooked until the mixture gels.
  • A quick cooking jam brings fruit and sugar to a boil, then adds commercially prepared pectin to form a gel.

Long cooking jams use about 4 parts of fruit to 3 parts of jam. So, a recipe that calls for 4 cups of berries needs 3 cups of sugar to properly gel.

Quick cooking jams require nearly an equal amount of sugar as fruit, and sometimes even more sugar than fruit. A recipe that calls for 4 cups of berries needs anywhere between 3 ½ – 5 cups of sugar for the jam to gel.

Fruit butters, which are thickened by cooking and pureeing fruit and sugar until the desired texture, require half as much sugar as fruit. A recipe that calls for 4 cups of fruit puree needs only 2 cups of sugar. The difference is because fruit butters don’t gel, they cook down into a more concentrated form.

Can I Use Honey Instead of Sugar When Making Jam?

Honey or maple syrup can be used instead of some of the sugar when making jam. This is especially true when making a long cooking jam. You can replace half of the sugar with either honey or maple syrup. I often use honey with peach or pear jams, and maple syrup is lovely with blackberries or cranberries.

Can I Use Less Sugar When Making Jam?

I am asked this question over and over. We all want more jam – but less sugar! I understand, but we cannot haphazardly reduce the sugar content in our jam recipe. Only recipes that have been specifically developed for a commercially prepared low sugar pectin can be made with less sugar. Why, you ask?

The Role of Sugar

Sugar isn’t just sweet on the tongue, it’s a hard worker too, doing several necessary jobs in every batch of jam.

Fruit Stability: Have you ever made preserves? Preserves are made by macerating chopped pieces of fruit in sugar, and then cooking the combination until it gels. Instead of the fruit cooking down into a “jammy” concoction, the end result is almost like fruit pieces suspended in jelly. The sugar helps the chopped fruit retain its shape and texture.

Gel: Sugar is one of the three necessary components for jam set, or gel. Sugar molecules grab onto water molecules as the mixture is heated. This allows the pectin to form a gel. If there is too little sugar added, the pectin will be diluted and will not form a gel.

Keeps Bacteria Away: Sugar molecules can be quite thirsty and like to pull as much water away from the mixture as they can. As a result, they also pull water from any microbes that are lurking around. Just like we can’t live without water, neither can microbes. When sugar pulls the water out of the microbe cells, it effectively kills them. This makes sugar an excellent food preserver, if enough is added to the mixture.

What About Low-Sugar Jams?

As mentioned above, low-sugar jams can be made only using low-sugar pectin products like Ball® RealFruit® Low or No-Sugar Needed Pectin or Pomona’s Universal Pectin™. You must also use a recipe designed for a low-sugar pectin for the jam to successfully set.

Low sugar jams have a shorter shelf life than long cooking or quick cooking jams.

Some freezer jams also use less sugar, because they only need enough sugar to form a gel, not enough to actually preserve the product since it is stored in the freezer. However, other freezer jam recipes use large amounts of sugar – so read your recipe carefully.

Whew! That was a lot of explaining to answer a simple question. Basically it boils down to:

  • No, you can’t use less sugar in your jam recipe, and
  • Be sure to follow the recipe you have chosen!

Jam Making Basics Series

Check out these other posts in this series

Jam Making Basics – What is Pectin?

by Renee Pottle

Renee Pottle, a freelance writer and Home Economist, is fanatic about all things food. She blogs about canning and food preservation at SeedToPantry.com. Find her professional food writing info at PenandProvisions.com.

April 9, 2019

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