diff --git a/src/message/header/content.rs b/src/message/header/content.rs
index e74fd57..866c6c9 100644
--- a/src/message/header/content.rs
+++ b/src/message/header/content.rs
@@ -21,7 +21,7 @@ pub enum ContentTransferEncoding {
 
 impl Default for ContentTransferEncoding {
     fn default() -> Self {
-        ContentTransferEncoding::SevenBit
+        ContentTransferEncoding::Base64
     }
 }