diff --git a/lib/request/basic.py b/lib/request/basic.py
index fb92fe1fc..124649d8e 100644
--- a/lib/request/basic.py
+++ b/lib/request/basic.py
@@ -186,8 +186,9 @@ def getHeuristicCharEncoding(page):
     """
     retVal = detect(page)["encoding"]
 
-    infoMsg = "heuristics detected web page charset '%s'" % retVal
-    singleTimeLogMessage(infoMsg, logging.INFO, retVal)
+    if retVal:
+        infoMsg = "heuristics detected web page charset '%s'" % retVal
+        singleTimeLogMessage(infoMsg, logging.INFO, retVal)
 
     return retVal