This is where the alcohol from the stills is condensed. It is cooled by the waters of the Edradour Burn. It is one of the few places where a natural process of cooling is used to condense the alcohol.
http://www.edradour.com/~edr99/explore/unique-features/
Edradour's claim to fame is that they are the smallest distillery in Scotland.
https://en.wikipedia.org/wiki/Edradour_distillery