Symfony2: setting a cookie

I'm trying to set a cookie within a login controller to achieve "remember me" system. Even though I've used the exact code I found on the web, things for me are going wrong. I hope you can help me figure out what I'm missing.

Let's go through the code:

public function loginAction(Request $request) {
// Receiving the login form
// Get Doctrine, Get EntityManager, Get Repository
if(/* form information matche database information */) {
     // Creating a session => it's OK
     // Creating the cookie
     $response = new Response();
     $response->headers->setCookie(new Cookie("user", $user));
     $response->send();
     $url = $this->generateUrl('home');
     return $this->redirect($url);

} else 
     return $this->render('***Bundle:Default:Login.html.php');
}

I included these:

use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpFoundation\Cookie;

Note that logging-in works fine, the session has been created, but the cookie hasn't.