diff --git a/mongoengine/document.py b/mongoengine/document.py
index 5edfc810..563f57a4 100644
--- a/mongoengine/document.py
+++ b/mongoengine/document.py
@@ -202,7 +202,7 @@ class Document(BaseDocument):
             self.validate(clean=clean)
 
         if not write_concern:
-            write_concern = {}
+            write_concern = {"w": 1}
 
         doc = self.to_mongo()