After searching my site on Google I have found that the URL that is shown doesn't contain www at the beginning, why?

This is my virtualhost:

<VirtualHost *:80>
  ServerName estebancortijo.com

  Redirect / http://www.estebancortijo.com/
</VirtualHost>

<VirtualHost *:80>
  ServerName www.estebancortijo.com

  SetEnv MYAPP_ENV prod

  DocumentRoot /var/www/jesusesteban/web
  <Directory /var/www/jesusesteban/web/>
      # Options Indexes FollowSymLinks MultiViews
      AllowOverride None
      Order allow,deny
      allow from all
      <IfModule mod_mime.c>
          Addtype font/truetype .ttf
          AddOutputFilterByType DEFLATE text/html text/plain text/xml text/css font/opentype font/truetype
      </IfModule>
      <IfModule mod_rewrite.c>
          Options -MultiViews

          RewriteEngine On
          #RewriteBase /path/to/app
          RewriteCond %{REQUEST_FILENAME} !-f
          RewriteRule ^ index.php [QSA,L]
      </IfModule>
      <IfModule mod_expires.c>
          ExpiresActive On
      ExpiresDefault "access plus 10 days"
      ExpiresByType text/css "access plus 1 week"
      ExpiresByType text/plain "access plus 1 month"
      ExpiresByType image/gif "access plus 1 month"
      ExpiresByType image/png "access plus 1 month"
      ExpiresByType image/jpeg "access plus 1 month"
      ExpiresByType application/x-javascript "access plus 1 month"
      ExpiresByType application/javascript "access plus 1 week"
      ExpiresByType application/x-icon "access plus 1 year"
      </IfModule>
    </Directory>
</VirtualHost>

I have the same configuration for another site, but in that case the www is shown in Google results.

Any idea?