Laravel 5.7

config/mail.php

@@ -120,4 +120,17 @@ return [
         ],
     ],
 
+    /*
+    |--------------------------------------------------------------------------
+    | Log Channel
+    |--------------------------------------------------------------------------
+    |
+    | If you are using the "log" driver, you may specify the logging channel
+    | if you prefer to keep mail messages separate from other log entries
+    | for simpler reading. Otherwise, the default channel will be used.
+    |
+    */
+
+    'log_channel' => env('MAIL_LOG_CHANNEL'),
+
 ];