- 1 dry quart (about 650 grams) fresh blueberries
- 1 cup (200 g) granulated sugar
- 1 tablespoon grated fresh ginger
- 1½ tablespoons lemon juice (juice of 1/2 lemon)
- 1 tiny pat unsalted butter
prepare jars and other equipment
Since you’re making only 5 tiny jars of jam, you can use a smaller pot for the boiling waterbath – use any pot that will hold the jars and enough water to cover them by 1-2 inches. Put empty clean jars in a pot, add water to at least an inch over the tops of the jars, and bring the water to a boil. Remove jars, and let them drain upside down on a folded towel. Don’t drain the water from the pot; you’ll use it shortly.
Wash the lids in warm water and set aside (see new procedures for jar lids!) Keep the bands handy. Have an extra small jar, or custard cup, clean and ready for any excess jam.
prep the blueberries and cook
While the empty jars are coming to a boil, rinse the blueberries well and discard any that are green or moldy. Put them in a heavy-bottomed skillet, and mash them to bits. Add the sugar and lemon juice, stir well to combine. When the mixture looks a bit syrupy, put the skillet over medium-high heat, and add the grated ginger and a teeny-tiny pat of butter. (The butter is optional, but it does reduce foaming) Bring the blueberry mixture to a boil, stirring often. When the berries are completely cooked, briefly remove the pot from the heat. Whiz the preserves with an immersion blender to make a smooth puree.
cook until you can make a clean streak
Return the skillet to the heat, and continue cooking, stirring often, until it bubbles and looks quite thick. It’s done when you can pull a spatula through the jam and a streak remains: it doesn’t immediately fill in again.
seal in boiling waterbath
When the jam is ready, remove the pot from the heat. Ladle jam into prepared jars, wipe rims, and apply lids and bands. Anything that won’t fit in your four jars can go into the clean custard cup – chill it in the fridge, this is perfect with yogurt or on toast for breakfast!
Wipe the jar rims, apply lids and bands, then process for 10 minutes in a boiling water bath. Cool jars, label, and store in a dark cool place.
This recipe is adapted from Marisa McClellan’s Blueberry Jam with Crystallized Ginger, published in her splendid book Preserving by the Pint. I’m also a big fan of her blog, Food in Jars. Check it out!