Prepare canner, jars and lids.

Prepare and measure out 4 cups of mashed strawberries and add to a large stainless steel bowl.

Add the calcium water and stir well to combine.

In a separate bowl, add the pectin to the sugar and mix well to combine.

Bring mashed strawberries to a boil and add the pectin-sugar mixture. Stir to dissolve and continue stirring until the mixture returns to a full boil. Boil, stirring constantly for 2 minutes. Then remove from heat.

Place sugar, lemon juice and mashed strawberries in a large pot and bring to a boil. Simmer for 15-30 minutes or until you pass the frozen plate test for checking its readiness. 1. The Frozen Plate Test (Most Popular)Pre-chill: Place 2-3 small, clean plates in the freezer right when you start making your jam. Test: When your jam looks thick, remove the pot from the heat (so it doesn't overcook) and drop a small spoonful of hot jam onto one of the chilled plates. Freeze: Return the plate to the freezer for 1 to 2 minutes.Check: Push the edge of the jam with your fingertip or a spoon. Ready: The jam's surface wrinkles slightly and stays separated, moving as a single mass without seeping back together. Not Ready: The jam is runny and immediately fills the line you created. (If this happens, put the pot back on the heat for 1–2 minutes and repeat).

Ladle hot jam into prepared jars, leaving ¼ inch headspace.

Remove air bubbles and adjust headspace as needed. Wipe rims, place lids on top and screw down bands.

Place jars in canner and ensure they're completely submerged in water before placing the canner lid on. Bring water to a boil and process for 10 minutes. (If you're above sea level, adjust time for altitude by adding 1 minute for every 1,000 feet above sea level.)

Once time is up, turn off the heat, take the lid off the canner and set the timer for another 5 minutes before removing jars from the hot water. Once 5 minutes is up, remove jars from the canner and let them cool on the counter completely before storing in a cool, dark place.