I recently drove past a number of old Kentish oast-houses, which were once used for drying the hops used in beer making. Thought I should look the word up! Fascinating to find that oast derives from the Latin for summer:

From MW :
Main Entry: oast
Pronunciation: 'Ost
Function: noun
Etymology: Middle English ost, from Old English Ast; akin to Middle Dutch eest kiln, Latin aestus heat, aestas summer
Date: before 12th century
: a usually conical kiln used for drying hops, malt, or tobacco -- called also oast·house \-"haus\

A picture of a double oast:

http://www.nina.gemineans.co.uk/pics/history/indust/oasthse.JPG