Just look for Yelp 1-star reviews on coffeeshops. I reckon that should work. I know this sounds like a facetious answer, but any app that does what you asked fo

Just look for Yelp 1-star reviews on coffeeshops. I reckon that should work. I know this sounds like a facetious answer, but any app that does what you asked for would probably return results that correlate with the quality of the coffee.