There is a difference between a clean beer glass and a beer clean glass.

A clean beer glass means that it is sanitized and nobody is getting ill. Check.

Beer Clean is an industry term to explain that a beer glass is free from oil and grease inside the glass. And...it has a massive impact on how your beer is going to taste and look.

Here's what you need to know:

Dirty glasses have an invisible film of oil and grease on the inside.

This is caused by putting fingers, soft drinks, dairy-based drinks, or napkins inside the glass. Or by running your beer glasses through the dishwasher, not the glasswasher.

This gives the beer poor head retention and makes it go flat quickly.

A Beer Clean glass has lacing - Rings of foam left on the inside of a freshly consumed pint glass, like the pint on the right in the image below. The beer looks and tastes better, leading to higher re-order rates.

Guests will usually return a pint in a dirty glass as they claim it tastes and looks flat. It will also taste different that one in a clean glass. Returned pints leads to lower margins and unhappy guests.

Most pint glasses in the industry are not beer clean.