If your jam or jelly is too thick, the first question to ask is: Is it spreadable? The Pomona’s jell could be stiffer or firmer than you are used to, but it should be spreadable. If it’s not spreadable, then something went wrong.
The most usual cause for a too firm or rubbery texture with Pomona’s is that you used less fruit than the recipe called for. Our recipes are calculated for mashed fruit. So if you use pieces of fruit or whole berries, you are actually using less fruit than if it were mashed, or cooked to a mash and then measured, and you will get a firmer jell. Or you may have used more pectin than the recipe called for. For example, if you used Tablespoons of pectin rather than teaspoons.
Cooking can also affect the amount of fruit you are working with. For example, if you cook the fruit mixture for too long before adding pectin, you could reduce the fruit volume and make the pectin amount too high for the fruit you have left.
It is less likely that your jam would be too firm from overcooking after adding the pectin. Usually if you cook jam made with Pomona’s for too long after adding the pectin, it will de-activate the pectin and you will get a poor jell.
All of this being said, the typical Pomona’s jell is more like a fruit spread than a gloppy high-sugar jam. If you prefer a softer set, you can always use less pectin than called for in our recipes. We would suggest you experiment by using ¼ to ½ teaspoon less pectin than the recipe calls for, or perhaps up to a teaspoon less for recipes that call for 4 teaspoons of pectin. You would keep the calcium water amount the same.