Not to be confused with jam, jelly is a crystal-clear fruit preserve that tastes like candy and turns your favorite summer produce into a firm spread. Jelly's special flavor and consistency is why many cooks love to use it to add extra flavor to sweets and other foods, and jelly always tastes the best when you make it yourself.

Making jelly takes a bit of care, and one critical step is gauging whether your jelly is done cooking or not. There are different ways to test if your jelly is ready, but a simple temperature test is best, since you need to make sure the fruit hits its gelling point, or the temperature at which it turns from watery fruit into a firm jelly.

Towards the end of the cooking process, check your jelly’s temperature by using a candy thermometer; if the temperature reads at 220 degrees F, it’s ready. However, if you live at a higher altitude, figure out how many feet above sea level you are, and subtract two degrees from 220 for every 1,000 feet above sea level.

Two other methods to measure your jelly's progress are the spoon test, in which you dip a spoon into the spread and see if it firms up and forms a "sheet" on the spoon, and the freezer test, in which you put a little jelly in the freezer and see if it freezes solid. The temperature test is still the most reliable and least fussy method.