diff --git a/lib/segment/analytics/request.rb b/lib/segment/analytics/request.rb
index 5fcb1c2..344ab75 100644
--- a/lib/segment/analytics/request.rb
+++ b/lib/segment/analytics/request.rb
@@ -113,7 +113,7 @@ def send_request(write_key, batch)
 
         if self.class.stub
           logger.debug "stubbed request to #{@path}: " \
-            "write key = #{write_key}, batch = JSON.generate(#{batch})"
+            "write key = #{write_key}, batch = #{JSON.generate(batch)}"
 
           [200, '{}']
         else