Kids making Toffee?

The question mark in the title is not accidental. William had Teagan over this afternoon. She is moving away in two weeks, so he'd like to get the most time with her he can. They wanted to make toffee so I let them. I did suggest that vinegar in toffee didn't sound appetizing, but they followed the recipe and had lots of fun. However, the end product was not chewy and tasted terrible.