Acid does matter.....orange juice is not acedic enough. Buy oranges and you won't need any pectin, there is lots in the peel and pulp
What you were trying to make was "orange jelly"...mot marmalade.

My marmalade is whole fruit, twice the weight of the fruit in water, and twice the weight of the fruit in sugar.

Slice the fruit, remove the seeds if any (place them in a small piece of muslin, secure with kitchen string and add to the soaking fruit, boil it with the fruit and remove before adding the sugar) and place the sliced fruit in a very large pot to steep overnight in the water.

Nest day, boil the fruit and water until the peel is tender, then add the sugar and boil until setting point is reached. It will fizz up a lot as you boil it, which is why you need what seems at first to be a ridiculously large pot. Let it stand a few minutes then ladle into jars.

I've used this method for decades and used oranges, lemons, limes, mandarins and cumquats or a mixture of whatever citrus I had. It always works. :-)

Annie's recipe....which is divine if I do say so!

Orange Marmalade
2 cups thinly sliced orange rind
1 quart chopped orange pulp
1 cup thinly sliced lemons
1 1/2 quarts water
5 cups sugar

1. Add water to fruit and simmer 5 minutes.
2. Cover and let stand 12-18 hours in a cool place.
3. Cook rapidly until peel is tender, about 1 hour.
4. Measure fruit and liquid.
5. Alternate sugar with each cup of fruit mixture.
6. Bring slowly to a boil, stirring until sugar dissolves.
7. Cook rapidly, about 25 minutes.
8. When mixture begins to thicken, stir occasionally to prevent sticking.
9. Pour hot into hot jars, leaving 1/4 inch head space.
10. Adjust caps.
11. Process 10 minutes in boiling water bath.
12. Yield: about 7 half pints.

Also notice that you have to leave the fruit sit 12-18 hours so be sure to
time this so it'll be ready to start cooking when you are. I started mine on
Saturday night and made marmalade on Sunday afternoon after I came home from
the farm.

Good luck, it's worth it, trust me. This is yummy stuff.

Annie

And I always remove the peel with a potato peeler and cut out the fruit so as to leave behind most of the bitter white stuff. Labor intensive....but very yummy!

Thanks for the suggestions. I'd add that calamondins are *intensely* acidic. My granddaughter eats 'em with two fists (kids *love* sour stuff....) but I'm pretty sure if an adult eats one, they'd die of ascorbic acid overdose. ;-) Juice and pulp went in, along with the shredded peels. And the juice and zest of one lemon. Temp was brought up to 224F, as 223-224 was the target temp in one recipe.

I'll check the pH with some test strips, but these 'bottom out' around 2.0.

I thoughtg you said you used orange juice?

He used orange juice instead of the water in the recipe to "stretch out" the limited amount of the special oranges she had. At least that's how I read her post.

My aunt in Florida used to make marmalade from her oranges. I don't know what kind. It was intensely sour and I loved it. She would gift me a small precious jar for Christmas once she found out how much I liked it. Still trying to find a commercial marmalade that approaches it.

Linnea, perhaps your aunt's were Seville oranges? Sevilles are very bitter.

Apg4, how ripe was your fruit? Very ripe or overripe fruit has less pectin.

Very ripe....and the fruit peeled easily. Calamondins peel like miniature tangerines - except for their extreme acidity and sour/bitterness. And seeds.... Big, full sized seeds. pH of the juice/pulp mixture was 3.5, which should be plenty acidic. A little bit of gelatin, a tad more pectin on re-boil and it passed the gel test. Flavor is great....

BTW, I'm 70 with a full beard....

Cheers

Consider experimenting with Clear Jel next year (regular, not instant). The consistency of the marmalade will be different (saucy rather than gelatinous), but Clear Jel doesn't care how acidic the fruit is. Also, you don't have to boil the fruit to death before canning. You can easily adjust the thickness of the product before canning. If reduced sugar is wanted, mix a tiny amount of stevia powder with the sugar.

I've had calamondin as a house plant and wish I was in a climate to grow it outdoors.

I built a greenhouse just to have a place for the calamondin to stay for the winter. (It's Zone 8 hereabouts.) Moving it in and out is getting to be a real chore....