I WAS WONDERING HOW FRUIT SETS TO JAM WITH NO ADDITIONAL PECTIN? I AM SORRY FOR MY IGNORANCE BUT AS I STATED, I AM VERY NEW TO MAKING JAMS. ACTUALLY, I HAVE NEVER PUT ANYTHING UP BEFORE. YOUR RECIPES CAUGHT MY ATTENTION BECAUSE I HAVE AN UNCLE WHO IS NOT TOLERANT OF ADDITION PECTIN FOUND IN COMMERCIAL PRODUCTS.
I know your family will enjoy your jams. I always say that no matter if they don't gel or gel too hard, they still taste delicious and I've never had any trouble getting my family to destroy the evidence from my failures!
Pectin is a natural fiber found in fruit. The tricky part is that different fruits have different amounts, and also the amount differs whether the fruit is ripe or not (the less ripe, the more pectin). For example apples and grapes are VERY high in pectin and you can actually make home made pectin from windfall apples, I can send you a recipe if you need one. Most berries have plenty of pectin and stone fruit has just about enough. The trick is to use a fruit with enough pectin (berries) or use a combination of ripe and slightly unripe fruit (peaches, nectarines) or use a combination of fruits (apples and something else).
Anyway, my recipes work because I use fruits with natural pectin and then cook them very slowly and patiently to remove the water. Jams will almost always work this way, sometimes in fact mine get a little stiff. Jelly is a different story. My jellies most of the time don't work - I just put a pretty label on them that says "strawberry ice cream topping" or "plum pancake syrup" and get rave reviews. But jelly is just hard to make period, it gets cloudy, it doesn't gel, etc, etc, even if you use commercial pectin. It's just tricky stuff and I don't do very many.
I'd say for your first try head out and get some firm nectarines. They are plenty sweet and the hard ones still have good pectin. The color will be lovely and the flavor will be wonderful.