diff --git a/DependencyInjection/KnpGaufretteExtension.php b/DependencyInjection/KnpGaufretteExtension.php
index a0c7134..39e9d47 100644
--- a/DependencyInjection/KnpGaufretteExtension.php
+++ b/DependencyInjection/KnpGaufretteExtension.php
@@ -87,6 +87,7 @@ class KnpGaufretteExtension extends Extension
         ;
 
         if (!empty($config['alias'])) {
+            $container->getDefinition($id)->setPublic(false);
             $container->setAlias($config['alias'], $id);
         }