Stainless vs aluminum

[txtrnr]

What's the best/easiest way to tell difference between kegs?

 

[hunter_le five]

Pick it up. SS is WAY heavier than aluminum.

Also, because aluminum is far less dense than steel, it feels different when you rap your knuckles on it.

Also, aluminum tends to have a dull sheen, whereas SS is highly reflective.

The vast majority of kegs out there are SS, so odds are, it's SS.