Many traditional recipes use an equal amount of sugar to fruit, by weight, but I find it’s okay to decrease it to these proportions. Sugar is both a thickener and a preservation agent. If you reduce it too much more, your jam may not thicken and won’t keep for a long time. (Which is okay if you want thinner jam, you keep it in the refrigerator, and eat it relatively quickly.) This recipe can be scaled up or down, depending on how many strawberries you have. But if you want to make a lot more, best to make it in a couple of batches. To prepare the jars, pour boiling water into them, as well as into the lids. Let them sit 5-10 minutes, then carefully pour out the hot water and set them upside down on a cooling rack until ready to fill. Since I keep my jams in the refrigerator, I don’t put them up them in a traditional sense. I usually just overturn the jars and let them cool, which provides a reasonable seal, then refrigerate them. I find my jams keep well this way for up to one year. Check the National Center for Home Food Preservation website for instructions on how to can fruit jams. Note: Last season strawberries tend to have less natural pectin than ones that arrive earlier. So your jam may be less jelled. One strategy is the finely grate a green apple into the strawberries before cooking them, which adds pectin. (There are guidelines here for using liquid and powdered pectin.) I don’t mind the slightly runnier jam and it’s terrific on yogurt or served with fresh goat cheese for dessert.