acescent

Turning sour; readily becoming tart or acid; slightly sour.

The fluid was a pale yellow , thick , creamy - looking substance , of uniform consistency . It had a disagreeable acescent odour, something resembling that of putrecsent milk.

All kinds of malt liquor contain […] alcohol or spirit. They are of course weaker than wines, and in general more liable to become flat and acescent from this circumstance […]

A substance liable to become sour.