Low Sugar Strawberry Pineapple Jam

Now and Later, to Keep and Share

Recipe by Robin

Strawberry season. Here on the central CA coast, we are blessed with a long one, often beginning in late April and sometimes extending into November. In fact, it was the prospect of a season-long supply of Live Earth Farm strawberries that inspired me to sign up for their weekly CSA produce boxes.

By this time of the season, eating fresh strawberries is no longer a novelty, yet they’re still at their peak of flavor and freshness. We’ve eaten them plain, dipped them, drunk them, shortcaked them, frozen them, and even saladed or balsamic-minted them. What’s next? That’s right, strawberry jam!

Beginning to Look Like Jam

I created this recipe while attempting to make a low-sugar version of my great auntie’s strawberry pineapple jam from long ago. I’d scribbled a note to myself on her recipe: Try a Low-Sugar Version (8 cups).  8 cups in theory turned into 6 cups in practice, as I needed to cook it down more than I anticipated. This illustrates a major tenet in jam making: if it’s not gelling, cook it longer!

There are various methods of knowing when your jam is gelled. I like the direct approach: if you think it might be ready, chill a small amount and see if it seems like jam (details in recipe below). Different jam recipes produce different jam textures, from a loose spoonable crushed fruit texture to a classic firmer gelled texture. Since this is essentially an old school recipe, it tends towards firmer texture.

At First Strawberries Release Lots of Air

A few tools make working with boiling pots of water and jam less intimidating. A jar lifter adds control when adding and removing jars from hot water baths. A magnetic lid lifter does the same for the lids. A wide-mouth jam funnel makes it vastly easier to ladle the hot jam into the jars without waste and burn hazard. I also wear oven mits when stirring hot pots of jam, and while removing jars from hot water baths.

Boil Till Foam Subsides

Otherwise, you just need two big pots. The largest pot should be big enough to cover your jars with 2 inches of water and fit the number of jars of jam that you’ll be making snugly (you can add empty jars as spacers). This water bath is used both to pre-sterilize jars and to process them after filling with jam. An official canning pot has an additional rack, which makes it easy to load and unload jars for processing. This is very convenient, fairly inexpensive, and simplifies the processing, but I made jam for years without one.

Jam at the Gel Point, Ready to Jar

The smaller pot is where you’ll cook the jam. This must be non-reactive; either stainless steel or enamel is best. I currently use a deep 8-quart stainless steel soup pot. Some jammers like a wider shallower pot, which cooks the jam faster due to more surface area. However, a deeper pot eliminates jam splattering out onto the stovetop—and the chef.

This recipe is great for beginners because it uses commercial pectin, which reduces the chance of jam not gelling. Pectin occurs naturally in most fruits, but not in great quantity in strawberries. So we need to add some extra to get to the old school gel texture. Be sure to use Low (or No) Sugar pectin, not general-purpose pectin. Gel happens when pectin sugar, and acid combine chemically, so don’t adjust the amount of sugar. However, you may substitute regular white sugar for raw if you like. Note that I let the fruit sit with the sugar and pectin for an hour or two to macerate, but you can eliminate that step if you prefer. Happy jamming!

Passing the Gel Test: It's Jam!

Low Sugar Strawberry Pineapple Jam

makes 6 cups

1 – 20 oz. can no-sugar crushed pineapple

~ 4 pints strawberries

1 box low-sugar pectin (Sure Jell)

4 cups evaporated cane juice (raw sugar)

1 tbsp. fresh lemon juice

Sterilize clean jars by boiling in water for 20 minutes. This recipe makes about four 12 oz. jars, or five to six 8oz. jars. Boil an extra jar or two in case you need it. Remove jars with jar lifter and let drain inverted until dry. Put lids rings into bowl and cover with very hot (not boiling) water.

Put 2 – 3 saucers into freezer. You’ll use these later to test whether jam has gelled.

Open can of pineapple and measure in large measuring cup, without draining any liquid.

Wash, hull, and slice strawberries. Crush about 1 cup strawberries at a time with potato masher. Add enough strawberries to pineapple to make 5 ½ cups total. Be sure fruit is compacted, with no space between the berries.

In a deep 8 quart saucepan, mix low-sugar pectin together thoroughly with sugar, crushing all lumps. Add mixed fruit and lemon juice and stir to blend. Let it sit to allow fruit to macerate for 1 hour or more. Stir again.

Heat mixture over medium high heat till boiling, stirring constantly, about 10 minutes. Continue to heat and stir while strawberries release air bubbles. Cook until mixture stops foaming, about 12 minutes.

When foaming subsides, turn heat to high. Stir constantly until gel point is reached, about 10 minutes or less. Test jam periodically: remove jam from heat, drop a spoonful of jam on a chilled plate, return it to the freezer for a minute, and see if it slides down the plate in one blob like jam (see photo above). If it doesn't stay together, or runs in rivulets, keep boiling!

When test indicates that jam is gelled, remove jam from heat and fill pre-sterilized jar using a ladle and jam funnel. Fill to ¼ inch from jar top. Wipe rim of jar with damp cloth if jam has spilled (funnel should eliminate most of this problem). Pick up sterilized lid with lid lifter, and shake off water. Cap jar with lid. Screw on ring finger tight using only one finger--don’t screw on tight! Air will release during hot water bath processing. 

Process jars in a boiling water bath for 5 (4 oz jars) or 10 (12 oz jars) minutes. Remove from bath with jar lifters. Place hot jars on a towel—not onto a cold tile surface! Tighten up rings when cool enough to handle.

Let sit overnight, or at least 12 hours. Check tops of jars to ensure that lids have sealed; lids should not “snap” down when pressed with thumb. If any jars have not sealed, either reprocess them or store in refrigerator and eat within 2 weeks.