diff --git a/app/models/site.rb b/app/models/site.rb
index 1ebcba4..3cb268b 100644
--- a/app/models/site.rb
+++ b/app/models/site.rb
@@ -414,7 +414,7 @@ class Site < ApplicationRecord
   # TODO: Guardar la configuración también, quizás aprovechando algún
   # método de ActiveRecord para que lance un salvado recursivo.
   def sync_attributes_with_config!
-    config.theme = design.gem
+    config.theme = design.gem unless design.gem == 'sutty-theme-custom'
     config.description = description
     config.title = title
     config.url = url