Wash the baby food jar, lid and both marbles with liquid dish detergent. Dry the items thoroughly.
Chill baby food jars in refrigerator or set them on ice.
Pour room-temperature heavy cream into the jar until it is filled to just below the bottom of the threading.
Shake the jar in all directions while standing in an open area with plenty of space. Have fun with it. Throw on some music and shake the jar to the rhythm.
Pair up or shake in teams, so you can “hand off” the jar when your arms get tired.
Take off the lid after approximately 30 minutes of shaking.
Pour off the liquid buttermilk that has separated from the butter solids.
Add cold water to the jar until it is nearly full and use a spoon to form the butter solids together into a singular mass.
Pour out the water and press any remaining liquid out of the solid butter mass. Add a pinch of salt, if desired, before replacing the lid and storing your fresh butter in the refrigerator for up to a week.
Instructions
Tip:
Leaving behind even a small amount of buttermilk will cause your butter to spoil rapidly.
