Fresh tropical fruit juices — such as papaya, kiwi, mango, guava and pineapple — contain an enzyme called bromelain that prevents gelatin from setting. If you want to make jellies with these flavors, use processed (not fresh) juices, as pasteurization destroys the enzyme.
While you can make jellies with any fruit juice, clear juices such as apple (not cider), grape and cranberry will deliver more luminous results.
If you don’t have silicone molds, use a 20 by 10 centimeter loaf pan lined with foil and lightly greased. Once the jelly has set (about 90 minutes), turn it out onto a clean work surface and cut with a sharp knife into 12 cubes.
The jellies will keep in an airtight container in the refrigerator for up to one week.
Courtesy of THE 3-INGREDIENT BAKING BOOK by Charmian Christie © 2019 www.robertrose.ca Reprinted with permission. Available where books are sold.