Our Small Batch Sour Cherry Jam without Pectin is a delicious summer treat. Use it as a cake filling, swirl it into Greek yogurt, or simply spread it on toast. As the name implies, sour cherries aren’t as sweet as other types of cherries. In fact, they are often referred to as tart cherries. They are too tart to eat on their own, but with a little bit of sugar and love, they become magically delicious in this sour cherry jam recipe.