Description

This homemade blueberry jam recipe uses fresh blueberries, sugar, lemon juice, balsamic vinegar, and vanilla to create a luscious, naturally flavored spread. The jam is prepared over several days with gradual heating and simmering, resulting in a thick, flavorful preserve perfect for toast, desserts, or as a topping.

Ingredients

Scale

Jam Ingredients

2 dry pints blueberries (20 oz / 567 grams / roughly 4 cups)
16 oz sugar (454 grams / 2 slightly generous cups)
1.5 oz lemon juice (freshly squeezed, 43 grams / 3 Tablespoons)
0.5 oz balsamic vinegar (14 ml / 1 Tablespoon)
1/2 vanilla bean (split and scraped, substitute 1 teaspoon vanilla extract at the end of cooking)

Instructions

Prepare the fruit mixture: In a medium-sized, heavy-bottomed saucepan, combine the blueberries, sugar, freshly squeezed lemon juice, balsamic vinegar, and the split and scraped half vanilla bean (if using). Use a potato masher or similar tool to partially crush the berries to start releasing their juices.
Refrigerate overnight: Cover the saucepan and place it in the refrigerator overnight to macerate and fully infuse the flavors.
Heat gently: On the second day, remove the cover and place the pan over low heat for about an hour to gradually warm the mixture until it is hot. As the berries soften, mash them more thoroughly with your masher to release more juice and break down the fruit.
Simmer and cool: Bring the mixture to a high simmer and then remove from heat. Allow the jam to cool to warm temperature, cover, and then refrigerate overnight again to let flavors develop further.
Boil to set jam: On the third day, uncover and heat the mixture over medium to medium-high heat, stirring frequently until it comes to a boil.
Reach proper temperature: Boil the jam, stirring almost constantly to prevent sticking or burning, until it reaches 223°F (106°C), the typical temperature for jam setting.
Finish the flavor: Remove from heat, fish out the vanilla bean pod if used, or stir in 1 teaspoon of high-quality vanilla extract at this point.
Jar the jam: Ladle the hot jam into clean, sterilized jars. Seal the jars and invert them until they reach room temperature to help create a vacuum seal. Then return the jars to the upright position.
Storage: If you prefer not to quick-can, allow the jam to cool completely, cover, and store in the refrigerator where it will keep for up to 3 months.

Notes

Using a heavy-bottomed saucepan prevents hot spots and reduces the risk of burning the jam.
The slow heating and overnight resting steps enhance the fruit flavor and improve texture.
Measure the temperature with a candy or jam thermometer for best results to ensure the jam sets properly.
The balsamic vinegar adds subtle depth and balances the sweetness.
You can substitute the vanilla bean with vanilla extract added at the end of cooking.
Sterilize jars properly to extend shelf life and ensure food safety if you plan to store for longer periods.

Prep Time: 10 minutes (plus overnight resting time)
Cook Time: Approximately 1.5 hours total heating and boiling over three days
Category: Jam, Preserves, Spread
Method: Stovetop
Cuisine: American

Keywords: blueberry jam, homemade jam, preserves, fruit jam, how to make blueberry jam, stovetop jam, vanilla blueberry jam