Plum butter, what went wrong?

[JustJoel]

I made some plum butter; it's delicious, with hints of cardamom and cinnamon, but it's not buttery at all. It's as hard as rock! Did I simmer it too long? Too much sugar? I've got five pounds of nectarines waiting to be made into fruit butter, but don't want it to turn into nectarine hard candy, so I'm waiting for advice from you fine cooks out there! Help, please?

 

[blissful]

Did I simmer it too long?

Probably.

Temperature Test – Take the temperature of the jelly with a candy or jelly thermometer. When done, the temperature of the jelly should be 220°F, 8°F above the boiling point of water, if you are at sea level.

That is for jelly, but with jam, and fruit butter, you can't boil all the water out of it 212 degrees F, continue on upward past the 220 degrees F, without making taffy or eventually hard candy.

Fix: add water, bring up to 220 degrees F and see if your texture is better.