Prepare water bath canner by filling it with water, and setting it on the stove. Turn the burner to high. Once it reaches a boil, reduce it to simmer. You want to keep the water hot so that everything is ready when the jam is.
Wash and sanitize your jars. You can fill them with hot water, or place them on a tray in the oven at 200 degrees F.
Wash your lids and set aside in clean place.
Making Strawberry Jam
Rinse the strawberries. Remove the tops and cut in halves or quarters (8 cups total). Place in a heavy-bottomed saucepan.
8 cups strawberries
Heat the fruit over medium heat until the juices start to bubble. At this point, you can mash the fruit with a potato masher, or use an immersion blender (only blend 30% of berries).
In a small bowl, combine 1/2 tsp calcium powder with 1/2 cup cool water.
In a separate bowl, combine sugar (1.5 cups) and pectin (2.5 tsp). Set aside. To prevent clumping in the fruit, Pomona's must be mixed with your sweetener before being added to the fruit.
1.5 cups sugar, 2.5 tsp Pomona's Pectin
Add the lemon juice (1/4 cup) and calcium water (2.5 tsp) to the pot with the strawberries, stir.
1/4 cup bottled lemon juice, 2.5 tsp calcium water
Add the sugar/pectin mixture, and bring to a rolling boil. Stir constantly for 3 minutes, turning down the burner to medium if the jam starts popping.
At this point, turn the burner under the canner back up to high and get that water boiling again.
Remove the jam pot from heat, and stir gently for 5 more minutes. At the end of the 5 minutes, remove any foam that remains.
Using the funnel and a ladle, add the jam to your prepared jars, leaving 1/4 inch of headspace at the top. Headspace is the amount of room between the top of the food, and the rim of the jar.
Using a wet clean rag, wipe the rim to make sure there isn't any sticky jam on there.
Place a clean lid on the jar and then a ring. Tighten the ring to fingertip tight.
Using canning tongs, add jars to the boiling water, and put the canner lid on. Pro tip: you must have at least 1 inch of water over the tops of the jars for safe canning.
Process (boil) for 10 minutes.
Remove the canner from heat, and let sit for 5 minutes.
Remove the jars and place them on towels on the counter undisturbed for 12-24 hours.
After everything has cooled, check the seal by pushing down on the middle of the lid. If it doesn't give way, it's sealed. If the lid bows a little bit, put that in the fridge and use it within 3 weeks.
Label the sealed jars, and store in a cool dark place for up to a year.
Notes
Makes 5, 8 oz jars.8 cups fresh strawberries generally equal about 5 cups of mashed berries.Will last for 1 month in the fridge or 12 months sealed and at room temperature.