Making Low-Sugar Jams

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Photo by iStock/marcomayer.
Low in sugar and without commercial pectin, these jams showcase the flavor of the fruit.

The first time I made jam, our neighborhood grandmother, Agnes, told me I needed to buy a box of commercial pectin so my jam would set. I was pretty appalled by the amount of sugar required and thought the resulting jam was too sweet. It tasted more like sugar and less like the strawberries I had laboriously picked under the hot sun.

So I set about learning about making low-sugar jams without pectin, figuring people must’ve made jam before commercial pectins were sold. Pectin is a naturally occurring substance in the cell walls of ripe fruits and vegetables. When fruit is cooked and broken down, the pectin gives the preserve some structure and thickness so it doesn’t soak unpleasantly into toast or PB&Js.

Back before the advent of the supermarket, home cooks made preserves by simply cooking down their fruits with sugar. And even if they didn’t know anything about pectin, they knew that some fruits, such as ‘Concord’ grapes, jelled easily, but other fruits, such as strawberries, needed to be cooked down a lot. And they knew that all preserves benefited from a splash of lemon juice to help them set.

When commercially extracted pectin was introduced in the United States in the 1920s, cooks embraced this new convenience product. It took the guesswork out of fruit preserves and vastly reduced the time required to make jams and jellies. Of course, those original commercial pectins required that jams be made with white sugar and that the final jam be 60 to 65 percent sugar by weight. On the other hand, yields were greatly increased with commercial pectin because the fruit didn’t have to be cooked down so much, and little time had to be spent stirring the fruit to prevent scorching.

In the 1980s, Pomona’s Universal Pectin arrived on the marketplace. This pectin was formulated to work with the addition of calcium instead of great amounts of sugar. Soon, a few more brands of low- or no-sugar pectin became available.

If you want to make a preserve with a low- or no-sugar pectin today, you can just look for such a product wherever canning supplies are sold (usually hardware stores, supermarkets, or online) and follow the directions on the packaging.

Some brands are easier to use than others. Some contain tiny amounts of dextrose or preservatives. Some break down over time, so after a few months you may have runny jams or jams that separate in the jar. You can find plenty of opinions about different brands online. I happen to prefer Ball’s low- or no-sugar pectin. It’s less fussy to use than some of the other brands, it holds its set longer, and it allows me to sweeten to taste because I don’t have to pre-mix my sweetener with the pectin to prevent lumps (which is required by Pomona’s).

Before proceeding, there’s one important point to consider: Sugar in any form — granulated white, brown, maple syrup, and honey — is a preservative. Without any additional sweetener, preserves taste flat and don’t keep well. No-sugar jams with added pectin do just fine on the shelf if they’re processed in a boiling water bath or steam canner for 10 minutes. Likewise, no-sugar jams with no added pectin that are cooked down and processed for 15 minutes are also fine on the shelf. However, after they’re opened, they may develop mold or ferment quickly. Open jars of low- or no-sugar jams will keep for 10 to 14 days. High-sugar jams that are made with standard commercial pectin will keep for months in the refrigerator; they also tend to be lighter in color and have a firmer set.

If you’re worried you won’t finish a jar of low- or no-sugar jam before it goes bad, process the jam in 4-ounce jars (quarter-pint jars), but keep the processing time the same as specified in the preceding paragraph.

Over the years, I’ve played around with different fruits, different sweeteners, and different amounts of sweeteners. Here’s what I’ve learned.

Honey and maple syrup work fine in a jam, but they often compete with the flavor of the fruit, so consider using at least half white sugar and half other sweetener.

Very-low-sugar preserves can taste flat or sour. My family prefers a lightly sweetened jam. With added pectin, I generally use 2 cups of sugar or another sweetener to 6 pounds of fruit. When I’m cooking the fruit down, I generally use about 1-1⁄2 to 2 cups sugar or another sweetener to 4 pounds of fruit.

You can cook your fruit with a couple of finely chopped apples to add pectin to the mix, but apples will mute the other fruit’s flavor.

You can make jams and other preserves from frozen fruit. You can also make them with mixtures of fresh or frozen fruit, especially when you combine different types of berries or different types of stone fruits (peaches, nectarines, cherries).

When you make a preserve without added commercial pectin, you’ll have to figure out when the preserve is ready to be taken off the heat. Take it off too soon, and you’ll have a runny preserve; too late, and you’ll have an almost-solid spread with the taste of caramelized sugar. The easy way to tell whether your preserve is ready is to drop a small amount of the fruit mixture onto a chilled plate. If your finger leaves a distinct trail through the preserves, it’s done; if liquid flows back into your finger trail, it’s not done.

Process jams and other preserves in a boiling water canner or atmospheric steam canner to achieve a 1-year shelf life and to eliminate the chance of mold. A very short 5-minute processing time using sterilized jars is recommended only for full-sugar preserves. If you’ve added pectin to your low- or no-sugar preserve, process for 10 minutes. If you haven’t added pectin, process your low-sugar preserves for 15 minutes, in accordance with the guidelines from the National Center for Home Food Preservation.

Jams are more than a spread for toast! Use them instead of maple syrup on pancakes and French toast; ripple into homemade ice cream about 5 minutes before it’s done; use instead of fresh fruit for filled fruit bars (cookie base, jam middles, crumble topping); or use as a topping for angel food cake or pound cake. Jam can dress up any dessert.

Jams made with commercial pectin have a texture that’s more jelled; jams made without commercial pectin are more like a thickened fruit spread.

You can make unique jams by adding flavorings, such as herbs and spices or liqueurs and spirits. If you want to go that route, add flavorings sparingly so as not to overwhelm the fruit. I prefer my jams to taste like fruit, pure and simple.

Find recipes for making low-sugar preserves here:

Low-Sugar Blueberry Jam
Low-Sugar Peach Jam
Low-Sugar Sour Cherry Jam

Andrea Chesman cooks, writes, and teaches in Vermont, where she lives on a 1-acre homestead. Find her books Serving Up the Harvest and The Backyard Homestead Book of Kitchen Know-How in our online store.