When I buy coffee (either decaf or regular) at the convenience store and add 1/2 & 1/2, it lasts for several days and several re-heatings without curdling.
BUT when I make Keurig-type coffee using ANY of several different brands I buy at the supermarket, my coffee won't last until the next day and reheating. It will curdle overnight.
So, does the coffee in the Keurig-type cups just end up having a lot more acid in it from their manufacturing process?
Might it help with my Keurig-type coffee at home if I used the little 1/2 & 1/2 containers that a typical convenience store carries? I know the chemistry in those little containers is different so that they don't curdle as easily when left out. (Hence the difference in taste vs regular chilled 1/2 & 1/2). Maybe they are made with an intentional alkali Ph?