diff --git a/daphne/access.py b/daphne/access.py
index e18138a..2cd605d 100644
--- a/daphne/access.py
+++ b/daphne/access.py
@@ -68,3 +68,4 @@ class AccessLogGenerator:
                 length or "-",
             )
         )
+        self.stream.flush()
diff --git a/daphne/cli.py b/daphne/cli.py
index a036821..05fb48f 100755
--- a/daphne/cli.py
+++ b/daphne/cli.py
@@ -224,7 +224,7 @@ class CommandLineInterface:
             if args.access_log == "-":
                 access_log_stream = sys.stdout
             else:
-                access_log_stream = open(args.access_log, "a", 1)
+                access_log_stream = open(args.access_log, "a")
         elif args.verbosity >= 1:
             access_log_stream = sys.stdout