Sweet Things Should Be Soft

A guy I dated said this more than once after I'd baked some sweet creation that was not to his liking.  While I disagree with the statement, and also find it the perfect metaphor for our difficult relationship (me= not so soft. Or is it me= not so sweet?), it happens to be true in one instance.

I had a hankering for caramels, and thought a little bag of hand-made caramels tied with pretty ribbon would make a great gift enclosure, so I looked in an old Fannie Farmer cookbook for a recipe.  And by old, I mean copyright 1937. The recipe seemed quite simple, calling for just 4 ingredients: granulated sugar, corn syrup, heavy cream, and vanilla extract. The directions said to boil the mixture a total of 3 times, never getting hotter than 244 degrees, which, according to my candy thermometer, is the "firm ball" stage. "Firm ball" seems to describe caramels pretty well, so I dove right in.

Chocolate-topped, pecan-crusted toffee.

Oooh, presents!

Part of the test for doneness, says this recipe, is to drop a small amount into cold water and see if it forms a soft ball (first boil/238 degrees) or a "decidedly firm ball" (last boil).  My mixture did form these balls, but not at the specified temperature.  No, mine formed the soft balls at maybe 225 degrees, and formed a hard-as-a-rock ball at 238 degrees. By 244 degrees, I had invented Caramel Life Savers. 

While I wound up with candy in gift bags anyway, I wonder what went wrong.  I actually followed directions this time, knowing that candy-making does not leave much room for improvisation. I found a new recipe today for salted caramels, and notice the ingredient list is much longer: 3 kinds of sugar (white, brown, and corn syrup). heavy cream, butter, vanilla, and sea salt.  Does the additional sugar help stave off the hard crack stage?  Does the butter? I admit I am totally confounded by the science behind this problem, and to add to the confusion, the new recipe calls for heating the mixture to 255 degrees!

Can anyone help with this?