Saturday, August 11, 2012

Low Sugar Strawberry Jam

5 jars of jam
Strawberries in Winter

Recipe by Happy Girl Kitchen

Making strawberry jam is magical. First, there’s the delicious scent of cooking berries that rises from the pot and permeates the kitchen. Second, there’s the way the berries foam up to several times their original volume while cooking, as they release air. How can berries be so full of air in the first place? Then there’s the always-magical gel point, where boiling fruit settles down and becomes jam. Lastly, there’s the magic of opening a jar in the winter and spooning out memories of summertime fields. Now is the time to start preserving!

Whole strawberries in pot before cooking
Ready to Start Jam Making
I learned this recipe in a jam class hosted by local food preservationists Happy Girl Kitchen. If you’ve been reading this blog for awhile, you might notice that this is exactly like the apricot jam recipe I posted last year: same proportions of fruit, sugar, and lemon juice. Since this jam contains no added pectin, using these proportions of sugar, acid and pectin (in the fruit) ensures that your jam will gel. Don't mess with them.

Strawberries bubbling up to top of pot
Strawberries Releasing Air, Beware of Overflow
Strawberries behave very differently than apricots. As mentioned above, they’re full of air, so will foam up during the cooking process. For this reason (and also to reduce hot liquid splatters as the fruit boils), I use a deep 8 quart stainless steel pot. You’ll also need another deep pot to sterilize jars and hot-water process jam-filled jars.

Strawberries with Less Foam than earlier photo
Keep Cooking it Down
Other basic jam making tools are a hefty long handled wooden spoon or paddle, apron, heat-proof spatula (for scraping the last of the jam into jars), and oven mits. Useful jam-specific tools are jar lifters and lid lifters to maneuver jars and lids in hot water baths, a wide mouth jam funnel to direct jam messlessly into jars, a thermometer to measure temperature of the hot water processing bath and a ladle or liquid measuring cup to scoop the jam from the pot to the jars. You’ll also need a kitchen towel to set the hot jars onto. And have a damp paper towel on hand to wipe off jar tops before sealing. Do yourself a favor and gather all of these supplies beforehand.

Jam Continuing to Cook Down
Starting Change from Foamy to Glossy
Remember that the exact amount of jam you end up with depends on the density of your strawberries. I got 5 half-pints, but you might get more or less. For this reason, sterilize and extra jar and lid or two, in case you need them. I cut the original recipe in half, so feel free to double it if you have a big enough pot. Happy jamming!

Strawberry Jam
Makes 5 half-pint jars

5 lbs. organic strawberries
1 lb. evaporated cane juice (unrefined sugar)
¼ cup fresh lemon juice

Wash and hull strawberries. Drain very well and/or pat dry. Combine with sugar and lemon juice and cover. Let sit in a dark, cool place overnight. You can let it sit like this for 2 days if you need to, but be sure that the temperature stays cool.

The next day: Put two or three saucers into the freezer. You’ll use these later to test whether the jam has gelled.

Wash jars in hot soapy water and boil for 15 minutes in a pot of water that covers jars by 2 inches. Remove from water bath with jar lifter, and drain upside down on kitchen towel where you’ll be filling jars with jam. Don’t pour out the hot water, you’ll use the same pot to hot water process jars of jam.

Pour boiling water into a bowl and toss in clean lids. Leave the lids in the hot water till you need them. It’s easiest to use a (jam-making specific) magnetic lid lifter to get them out of the water.

Mash the fruit with a potato masher or similar hand-held tool. Put fruit in 8 quart stainless steel or enamel pan. Remember that it will foam up during the cooking process, so don’t use a smaller pot. Bring to boil.

Boil the mixture on a high heat, stirring constantly. Wearing an apron and oven mits helps prevent burns. Lower heat if strawberries foam up to within an inch of the top of the pot. Keep cooking and stirring till foaming lessens. Eventually you’ll only see foam around the edges. Keep stirring, to release the rest of the air (otherwise your jam will be foamy instead of solid). Once all the foam is gone and the mixture looks glossy you can start testing to see if the jam has gelled.

To test for gel point, remove a saucer from the freezer. Put a little blob on a chilled saucer and put it back in the freezer for just a minute or two until it cools. Then tilt the plate and watch how the jam runs. At the gel point it all comes down the plate in a unified blob, rather than small runny drips. View photo of gel point test. The gel point will be reached after approximately 30 minutes of boiling, but bear in mind that this can vary depending upon the amount of air and moisture in the berries.

When gel point is reached, remove from heat. Fill first jar to within ¼ inch of top, using wide-mouth jam funnel and measuring cup or ladle. Wipe the top of the jar with a damp paper towel. Fish a lid from the hot water with lid lifter and shake off water. Place on top of jar. Screw ring onto jar loosely, barely finger-tight. Avoid over-tightening as air must escape from the jar during the hot water processing.

Repeat this process with all jars until all jars are filled. If the last jar is only partially filled, don’t hot water process that one. Store it in the fridge and eat it within a few weeks.

To hot water process: Remove water from the large pot in which you sterilized the jars. Remove approximately the total volume of your jars. Reheat water to full boil. Remove from heat and use jar lifter to place each jar into hot water bath. Check water temperature. You will need to process at 210 degrees F.

Put heat under pot again and bring temperature to 210 degrees. Process for 5 minutes, keeping temperature constant. Remove pot from heat.

Use jar lifter to remove jars from hot water bath. Set each jar on kitchen towel. Don’t set directly on any cool or fragile surface. As soon as jars are cool enough to handle, tighten rings.

Cool for several hours or overnight. Lids must “snap” down to seal. If after cooling you can depress the center of a lid, it is not sealed. You can either refrigerate that jar and eat it within a few weeks or remove the ring and lid, wipe jar top and threads, and reprocess.


  1. I can't wait to try this recipe with berries!

    1. Let me know how it works out, Sheila! I've been wanting to try it with red raspberries but for some reason there haven't been any this year, only golden ones. Blackberries are starting to ripen down on the pathway to town, though--some potential jam there for sure. ;-)

  2. did you use castor or granulated sugar

    1. Hi,
      I actually used something called evaporated cane juice, which is a less processed form of sugar (Florida Crystals is the most economical brand I've found other than buying in bulk). However, I have also used granulated sugar in jam, it works fine. Caster sugar will work just as well...personally I don't use that in jam because where I am it is more expensive than granulated or bulk cane juice. Thanks for your question!