There are just four simple ingredients in this Small Batch Refrigerator Blueberry Jam made Without Pectin.
When I say this blueberry jam recipe makes a small batch of jam I really do mean a tiny batch. In fact, this recipe fills just one 4oz quarter pint jar. The perfect amount of homemade jam for one.
If you want to make a larger batch of jam the recipe is really easy to scale up.
Love blueberries? Try these Jumbo Blueberry Muffins.
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Why You Will Love This Recipe
- With only a couple of simple ingredients, the fresh sweet blueberries really shine in this jam.
- Making blueberry jam is one of the quickest ways to bottle up the last fresh berries of summer. This recipe takes just 20 minutes from start to finish.
- No canning knowledge is necessary. This recipe makes such a small batch there is no need to can the jam to save it for later.
What is pectin?
When looking through jam recipes you will notice the word pectin comes up often. Pectin is a naturally occurring thickening agent that helps jams and jellies set up properly when they cool. Different fruits have varying amounts of naturally occurring pectin.
Blueberries happen to be naturally high in pectin which is why we don't have to add additional pectin when making blueberry jam. When heated blueberries release their pectin. It then combines with the lemon juice to create a gel that thickens the jam as it cools.
Blueberries: You can use either fresh or frozen blueberries. Look for blueberries that are firm and have a deep rich purple-blue color. Avoid blueberries that are mushy or wrinkled.
Sugar: Nothing special here just plain granulated white sugar.
Lemon Juice: When blueberries and sugar are heated together, the blueberries begin to release pectin. The lemon juice bonds with the pectin, creating a gel that thickens your jam.
This is one time when bottled lemon juice is better than fresh lemons. Bottled lemon juice has a consistent PH. Fresh lemons vary in ripeness and PH making them unsuitable for setting jams.
Lemon juice also helps to balance blueberries' natural sweetness.
Kosher Salt: Kosher salt helps to bring out the natural sweetness in the blueberries.
Small Saucepan: The cooking time for this recipe is based on using a small saucepan. Using a larger saucepan increases the surface area, decreases the cooking time, but increases the risk of burning the jam.
Quarter Pint Jars: You could also store this jam in a plastic storage container, but I love the way the rich jewel tones of this jam catch the light in a glass container.
Potato Masher: A potato masher is helpful for smashing the blueberries and encouraging them to break down. You could also use the back of a spoon.
Prep. Place a small plate in the freezer to use for testing the jam. Wash and drain blueberries in a colander.
Cook the jam. Add blueberries, sugar, lemon juice, and salt to a small saucepan.
Bring to a boil and allow the blueberries to simmer and thicken for about 10 minutes. Gently smash the blueberries with the back of your spoon or a potato masher to encourage them to break down.
Test the jam. Take your frozen plate out of the freezer. Spread a small amount of jam across the frozen plate. The frozen plate will instantly cool the jam down so that you can determine how thick it is. Tilt the plate. If the jam slides across the plate quickly it needs to boil and thicken for longer. If the jam slides slowly it is done.
Pour the jam into a sterilized jar and allow it to cool to room temperature. Once cooled store the jar in the refrigerator for up to one month.
How do you know when the jam is done?
As the jam cools it thickens. To test a small amount of jam use the frozen plate method.
The frozen plate method
Spread a small amount of jam across a frozen plate. The frozen plate will instantly cool the jam down so that you can determine how thick it is.
Tilt the plate. If the jam slides across the plate quickly it needs to boil and thicken for longer. If the jam slides slowly it is done. If the jam doesn't move at all it is overcooked.
Use an Instant-Read Thermometer
You can also use an instant-read thermometer to test the doneness of your jam. Jam is set once it has reached a temperature of 220 degrees Farenheight.
An instant-read probe thermometer is an essential kitchen tool. It's not only great for testing the doneness of meat but also works for checking the internal temperature of baked goods and testing jams like this one. This thermometer from ThermoWorks is my favorite. It is recommended by America's Test Kitchen and is super fast and accurate.
Frequently asked questions
Yes, but frozen blueberries may be more tart than fresh blueberries so you may need to add more sugar.
In fact, frozen fruit might be the better choice. The jam tastes best when it is made with high-quality fruit. Fruit that is used for commercial freezing is always picked at peak ripeness. If using frozen fruit there is no need to thaw it before making jam.
Yes, as the jam cools it will continue to thicken, which is why using the frozen plate method mentioned above is helpful to tell when a jam has been fully cooked.
Sterilizing jars is easy. Either was them in hot soapy water or run them through a dishwasher cycle.
Allow the jam to cool to room temperature and then pour it into an airtight container. Store in the refrigerator for up to one month.
Refrigerated jam should be good to eat for at least a month. Always use clean utensils to retrieve jam from the jar to avoid contamination. Signs of spoilage include mold or yeast growth, change in color, or any off odors like the smell of yeast, alcohol, or fermentation.
- Don't overcook the fruit. The overcooked jam will be tough and rubbery. The mixture will seem too thin but will thicken up as it cools.
- Boiling sugar can easily cause burns. Use caution and be careful to not splatter the mixture.
- If you want to add fresh herbs to your jam, add them at the end of the cooking process to preserve their bright flavor.
Jam has so many uses beyond toast. I love using this homemade blueberry jam as a topping for waffles and pancakes. It also tastes delicious on top of vanilla ice cream, and scones, and stirred into plain yogurt, oatmeal, or a smoothie. But my favorite way to use this jam is at the bottom of this blueberry creme brulee.
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Thanks for Reading!
If you try this recipe, let me know! Leave a comment and rate it below! You can also snap a picture and post it on Facebook be sure to tag me @RaspberriesandKohlrabi.