Prep Your Station. Before you start, make sure you have very clean jars and lids, a funnel, a ladle (or clean measuring cup for scooping), and all your ingredients ready to go. This recipe depends a bit of on timing, and moves quickly once you get started.
Mash & Measure The Strawberries. Wash strawberries thoroughly, then remove the green tops and dice the strawberries. (A rough chop is fine here! We're just making them easier to mash.) Use a potato masher to mash the strawberries in a large bowl, then carefully measure out 4 level cups of mashed strawberries and set aside. If you use more or less, your jam may not turn out properly. (If you have any leftover mashed berries, you can add them to oatmeal, smoothies, yogurt, etc.)
Boil The Pectin Mixture. In a large saucepan, combine sugar, low sugar pectin, and water. Bring the mixture to a boil over medium high heat, stirring constantly until the mixture comes to a boil, with bubbles all across the surface. Boil 1 minute (use a timer!) then remove from the heat.
Stir In The Strawberries. Add the crushed berries to the saucepan and stir thoroughly for another full minute (set a timer!) to fully incorporate the pectin mixture and strawberry mixture. Make sure to mix well, so the jam sets up evenly!
Scoop Into Jars. As soon as possible, scoop the jam into the clean jars, leaving 1/2-inch of room at the top for the jam to expand in the freezer. Wipe the rims of the jars and cover with clean lids.
Set 24 Hours. Let the jam rest at room temperature for 24 hours. Try not to jiggle or jostle the jars during this time. Just let them set!
Chill or Freeze. After 24 hours, transfer the jars to the freezer for up to 1 year, or the fridge for up to 3 weeks. Thaw frozen jam in the refrigerator before using and use within 3 weeks once opened.