diff --git a/feedbackloop/main.py b/feedbackloop/main.py
index d016df201a9de1c3a7a488d4dbb31b4a48da2125..522b8cefa5ccf0309a9ab83bd1f0594d43a33cf9 100644
--- a/feedbackloop/main.py
+++ b/feedbackloop/main.py
@@ -38,7 +38,7 @@ def ingest(unseen, limit):
         db.session.commit()
 
 
-@manager.option('--days', default=30)
+@manager.option('--days', type=int, default=30)
 def expire(days):
     """Expire old entries from the database."""
     cutoff = datetime.now() - timedelta(days)