diff --git a/production.ini b/production.ini
--- a/production.ini
+++ b/production.ini
@@ -349,6 +349,8 @@ beaker.cache.sql_cache_long.key_length =
 ## file based cookies (default) ##
 #beaker.session.type = file
 
+## beaker.session.key should be unique for a given host, even when running
+## on different ports. Otherwise, cookie sessions will be shared and messed up.
 beaker.session.key = kallithea
 beaker.session.secret = change-me