SMTP auth without SSL

Hei All , 

I am using 25.2.13882 , I need to send alerts via email with authentication

I can see that by default it uses SSL or TLS , but in my case is not secured 

$config['email']['backend']         = 'smtp';
$config['email']['smtp_host']       = 'mail.server';          // Outgoing SMTP server name.
$config['email']['smtp_port']       = 25;                   // The port to connect.
$config['email']['smtp_timeout']    = 10;                   // SMTP connection timeout in seconds.
$config['email']['smtp_auth']       = TRUE;
$config['email']['smtp_username']   = 'myuser';
$config['email']['smtp_password']   = 'mypass';

tried :

$config['email']['smtp_secure'] = NULL; 
and 
$config['email']['smtp_secure'] = ''; 

both of them ended with authentication + secure and not only authentication