Strawberry Jam

Got this recipe for strawberry refrigerator jam from my Grandma.  

Only 4 ingredients!

First add the strawberries and mash them up a little. Then add the other ingredients and bring to a boil. 

Boil for 15-20 minutes. Stir often. 

Let jam rest 5 minutes then spoon into jars. 

My initial reaction to tasting it is that it is too sweet. Next time I would probably use 1/2 a cup less sugar.