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Where I live, late summer is the best eating time of year. Local produce stands are popping up on almost every corner. This time of year, I visit my favorite farm stand every day. I’ll pick up all our summer favorites, like peaches, corn, summer squash and watermelon, but my absolute favorite thing to buy is fresh local raspberries, which I use to make low sugar raspberry jam.
I’m a little obsessed with these local raspberries, because of their intense, bright, sweet-tart flavor. I think other people in my hometown love them too. They usually sell out early in the day. If I want to get enough raspberries to make my low sugar raspberry jam for the year, I have to get to the stand right as the delivery truck arrives! I make 3-4 batches of homemade raspberry jam every summer, so I have plenty for my family and to give away to friends.
If you don’t have a favorite local supplier of raspberries, you can use any fresh raspberries or even frozen raspberries for your low sugar raspberry jam. Frozen raspberries are less expensive, and they’re frozen the same day they’re picked, so they have great flavor. If you use frozen raspberries, measure them out while frozen, then let them thaw before using them in the recipe.
Making homemade raspberry jam is easy, but you will need a little bit of canning equipment:
- Water bath canner with canning rack
- 1/2 pint Mason jars with lids and rings
- Jar lifting tongs
- Canning funnel
- Magnetic wand for retrieving lids from hot water (optional)
You can find the jars, rings, canners and all the equipment at stores like Walmart or many grocery stores, or you can order a canning kit, like this Ball Enamel Water Bath Canner with Utensils, from Amazon. Most people only have to buy this equipment once, and it lasts a lifetime. The one exception is the jar lids and rings, which have to be replaced.
You will also need some of your regular kitchen equipment for this recipe:
- Potato masher
- Large, open pot, like a soup pot, for boiling the jam
- Wooden spoon or heat-proof silicone spatula, for stirring
- Large spoon for skimming
- Large liquid measuring cup
- Dry measuring cups and spoons
- Small ceramic plates
- Clean kitchen towels
Before you begin, sterilize 6 half-pint Mason jars. Check the jars by running your finger around the rim, to make sure they’re not chipped. A jar that’s chipped won’t seal properly.
You can sterilize the jars using the sterilize cycle of the dishwasher, or by boiling the jars on the stovetop for 10 minutes. I usually fill the canner with water, and use that to boil the jars. Use the jar lifting tongs to take the jars out of the water, and set the jars on a clean kitchen towel. Put 2 small ceramic plates in the fridge, because you will need those later for testing the jam.
Meanwhile, wash about 8 cups of fresh raspberries, and pick out any leaves that might be sticking to them. Eight cups of whole raspberries should yield 5 cups of mashed raspberries, which is what you need for this recipe.
You can mash the raspberries with a potato masher, or process them in a food processor using a pulse setting. For this jam, I mashed the raspberries with a potato masher.
If you’re like me and you want to make multiple batches of jam, I recommend making them one at a time. Doubling or tripling jam recipes will sometimes affect the cooking process.
A key ingredient to low sugar raspberry jam is low sugar pectin. You can usually find this in grocery stores near where the canning supplies are. Make sure you get the low sugar pectin and not the regular. Pectin helps the jam thicken. Pectin is made from apples, so you don’t need to worry that you’re adding artificial chemicals to your jam. This recipe simply calls for fruit, sugar, lemon juice and pectin.
Mix the fruit, lemon juice, pectin and 1/4 cup of sugar in a large soup pot, and bring that to a full boil. Then add the rest of the sugar to total 3 1/2 cups, and bring it back to a full boil for one minute. A full boil, also called a hard boil, is a boil that doesn’t go away when stirred. Stir the jam the entire cooking time so it doesn’t burn.
Yes, 3 1/2 cups of sugar is a low sugar jam recipe! A regular jam recipe would call for 7 cups of sugar! Regular jam is more sugar than fruit. The way I look at low sugar raspberry jam is that it’s a lot of sugar per recipe, but not per serving. A serving of this jam is usually one tablespoon, and it will add tons of flavor to your toast, yogurt, or whatever.
You might notice that this recipe is different from the one that comes with your box or container of pectin. I use ratios of fruit, sugar and pectin that will make a relatively thick jam, which is what I like. This jam has a spreadable rather than a pourable consistency.
Once the jam has come to a hard boil a second time for a full minute, you can test its texture. Remove the jam from the heat, and take one of the cold plates out of the fridge. Pour a small spoonful of jam on the cold plate. If the jam thickens up to a texture you like, it’s done.
If you test the jam and it’s still too runny, boil it for another minute and test again. If it’s too runny after that, you might need to add another 1/4 box of pectin and boil again. (I’ve actually never had to do that.) This batch was perfect after the first test.
Once the jam is cooked, use a large spoon to skim off the foam. There’s nothing wrong with the foam, but it doesn’t look pretty.
After the foam has been skimmed, let the jam sit for 10 minutes or so, then stir. This will help distribute the fruit chunks so they don’t float to the top when the jam is in the jars.
While the jam is resting, get the lids ready. The flat lids for the Mason jars need to soak in hot – but not boiling – water to activate their seals. I usually heat some water in a pan until almost boiling, remove it from the heat, then add the lids. If you have a magnetic lid wand, you can use that when it’s time to take the lids out of the hot water.
Fill the jam jars using a ladle and canning funnel. Make sure to leave about 1/4 inch of “headspace,” or empty space, at the top of the jar, so if the food expands during processing, the lid doesn’t blow off!
Wipe off the rims of the jars with a clean towel. Place the lids on the jars and secure with rings, but don’t screw the rings on too tight.
Place the rack inside the water bath canner and fill with water. Place the jars carefully in the canner. The water should cover the tops of the jars by at least one inch. Follow the directions that come with your water bath canner.
Processing time depends on how far you are above sea level, so check the recipe below. At the end of the processing time, use the jar lifting tongs to remove the jars from the water, and set them on a clean towel. Let them sit undisturbed for several hours, so they can seal. You know they’re sealed when the center of the lid is depressed slightly and doesn’t move when you press it with your finger. You might hear a popping sound when the lids seal.
Making your own jam is totally worth the effort! Homemade jam also makes a great neighbor gift. Give it a try and let me know how it turns out!
It's easy to make your own low sugar raspberry jam, with a bright, sweet-tart fresh fruit flavor! Try it, and you'll never want to go back to store bought!
- 6 half-pint Mason jars with lids
- 8 cups whole raw raspberries, to yield 5 cups mashed raspberries.
- 3 ½ cups white sugar
- 1 box low sugar pectin
- 3 tablespoons lemon juice, either fresh or bottled
- Potato masher
- Large wooden spoon or silicone spatula for stirring
- Large wide pot (like a soup pot) for cooking
- Water bath canner
- Canning funnel
- Jar lifting tongs
- Sterilize the jars by washing in the dishwasher on the sterilize cycle or immersing in boiling water for 10 minutes. Place clean jars on a clean towel. Put 2 small ceramic plates in the refrigerator, because you will need them later to test the thickness of the jam.
- Wash the raspberries, and pick off any leaves. Mash them with a potato masher, or process carefully with a food processor to get the texture you want. Measure the sugar, and reserve ¼ cup to mix with the pectin.
- Mix the pectin, lemon juice, and ¼ cup sugar in a small bowl or measuring cup.
- Place the raspberries in a large cooking pot, and add the pectin mixture. Over medium high heat, bring everything to a full boil that does not go down when stirred. Stir the entire time so the jam does not burn. At this point, add the rest of the sugar, stir well, and bring the jam back to a full boil for one minute. Turn off the heat and test the thickness of the jam by putting a small spoonful on a cold ceramic plate. If it’s thick enough, it’s done. If it’s too runny, add ¼ package more pectin, bring to a hard boil again for 1 minute, and test again with the second cold plate.
- Let the jam cool for 10 minutes, then stir to distribute the fruit. If the jam is too hot when you put it in the jars, the fruit chunks will float to the top. Meanwhile, place the Mason jar flat lids (not the rings) in very hot (not boiling) water to get them ready.
- Fill your jars, using the ladle and funnel, leaving 1/4 inch of clearance space at the top of the jar.
- Wipe the rims of the jars with a clean, damp towel. Place the lids on the jars and secure with rings. Do not screw the rings on too tight.
- Process the jars, following the instructions for your water bath canner. This jam requires 5 minutes processing at sea level, 10 minutes above 1000 feet altitude and 15 minutes above 6000 feet altitude.
- Remove the jars carefully with the jar lifting tongs, and set them on a clean towel. Leave them undisturbed for several hours or overnight to let them seal. You can tell they are sealed if the center of the lid is depressed slightly and does not move when pressed with your finger. Remove the rings so they don’t rust due to trapped moisture, or if you want to leave them on, at least remove them temporarily to make sure they are dry underneath. The jam lasts about a year in the pantry.