Regular coffee absolutely kills me! That, combined with other things during the day will make me feel as if my chest is going to burst open in flames so I really only drink decaf. Then I can chance it with the spicy or acidic foods.
I haven't had heartburn in years, and I drink too much coffee. Too much beer too. I think the 'guarantee' you speak of mostly applies to people who regularly consume animal products. I know I haven't had it at all since going vegan.