diff --git a/better_formats.module b/better_formats.module
index 0477d76..18a9c4d 100644
--- a/better_formats.module
+++ b/better_formats.module
@@ -457,7 +457,7 @@ function better_formats_get_default_format($mode, $node_type = '') {
 
     $types  = $type;
     $format = array();
-    $roles  = implode(',', array_keys($user->roles));
+    $roles  = "'" . implode("','", array_keys($user->roles)) . "'";
 
     // Prepare types for SQL.
     if ($mode !== 'block' && $per_node_type && $node_type) {