How can i loop through custom post type according to custom meta field?

Check this : Get posts by meta data OR title

The first piece of code is working and allow to make a query based on meta data

You could just get rid of useless stuff (or adapt if you want to use several keys) :

$args = array(
 'post_type' => 'wine'
,'meta_query' => array(
         'key'     => 'vintage'
        ,'value'   => '2005'
        ,'compare' => '='
        )
);

$query = query_posts( $args );