[zerocrates]

Had the same experience briefly returning to an office last year, some very unappetizing Coke Zero. I don't know how much Ace-K differs in this regard or if there's not really enough to matter but... not good.

Was not really something I previously thought of as really expiring in any meaningful sense.

[gpcr1949]

Acesulfame K is not sensitive to degradation at coke pH. In addition to acesulfame K coke zero reportedly contains aspartame as well so that was probably the cause of the off-taste.