Overriding log_error in Rails3 not working

I have this in my application.rb:
private
      def log_error(exception)
         super
         UserMailer.error_message(exception,
           clean_backtrace(exception),
           session.instance_variable_get("@data"),
           params,
           request.env
         ).deliver
      end

I'd like the errors emailed to me.

It doesn't seem to be calling that "log_error" at all.

Is this done some other way in Rails3?