diff --git a/servant/src/Servant/API/ContentTypes.hs b/servant/src/Servant/API/ContentTypes.hs
index 69be4813..f719aec5 100644
--- a/servant/src/Servant/API/ContentTypes.hs
+++ b/servant/src/Servant/API/ContentTypes.hs
@@ -120,10 +120,13 @@ data OctetStream deriving Typeable
 --
 class Accept ctype where
     contentType   :: Proxy ctype -> M.MediaType
+    contentType = NE.head . contentTypes
 
     contentTypes  :: Proxy ctype -> NE.NonEmpty M.MediaType
     contentTypes  =  (NE.:| []) . contentType
 
+    {-# MINIMAL contentType | contentTypes #-}
+
 -- | @application/json@
 instance Accept JSON where
     contentType _ = "application" M.// "json"