diff --git a/lib/volumen/server.rb b/lib/volumen/server.rb
index 9a4be0c..48db326 100644
--- a/lib/volumen/server.rb
+++ b/lib/volumen/server.rb
@@ -79,8 +79,8 @@ module Volumen
     end
 
     def published_posts
-      store.all.reject { |post| post.draft? || post.scheduled? }
-               .sort_by { |post| post.date_string || "" }.reverse
+      @published_posts ||= store.all.reject { |post| post.draft? || post.scheduled? }
+                                  .sort_by { |post| post.date_string || "" }.reverse
     end
 
     def site_payload