Definition of "undrinkable"

[…] but there was a peculiar aroma about that Oxo that no ox had ever provided, unless he were stalled in a chemist's shop, and it was not long before this ruse was discovered and another liquid thereby added to the undrinkables of life.

1938, The National Review, volume 110, page 514

Popping down a cork coaster, the bartender delivered Alan's next drink and plucked the empties and undrinkables as the music changed.

2018, Craig Hallam, Old Haunts