I read over the recipe more carefully. 12 cups of vinegar must have been a typo. We never used vinegar.
When we were poor Cuban refugees, we ate beans and rice every day. Now that we are rich, we still eat a lot of them.
I agree it must be a typo, I could see calling for 1/2 cup, but not 12.
I don’t know how or when or even why I got into the habit of beans and rice, but I sure do love them.