diff --git a/lib/mail-drop.js b/lib/mail-drop.js
index 8921542..7fa5c57 100644
--- a/lib/mail-drop.js
+++ b/lib/mail-drop.js
@@ -110,7 +110,7 @@ class MailDrop {
             });
         };
 
-        let raw = new PassThrough();
+        let raw = new mailsplit.ChunkedPassthrough();
         let splitter = new mailsplit.Splitter({
             ignoreEmbedded: true,
             maxHeadSize: MAX_HEAD_SIZE