diff --git a/config/initializers/session_store.rb b/config/initializers/session_store.rb
index bdaed01f..aed61f8c 100644
--- a/config/initializers/session_store.rb
+++ b/config/initializers/session_store.rb
@@ -1,3 +1,3 @@
 # Be sure to restart your server when you modify this file.
 
-Rails.application.config.session_store :cookie_store, key: '_code_ocean_session'
+Rails.application.config.session_store :cookie_store, key: '_code_ocean_session', expire_after: 1.month