diff --git a/solr.cfg b/solr.cfg
index 2ea4bd8..7a1bf60 100644
--- a/solr.cfg
+++ b/solr.cfg
@@ -75,3 +75,4 @@ index =
     name:reception_date   type:date stored:true
     name:mail_date        type:date stored:true
     name:meeting_date     type:date stored:true
+    name:sortable_title   type:string stored:true