diff --git a/src/edu/internet2/jenkins/DockerBuild.groovy b/src/edu/internet2/jenkins/DockerBuild.groovy
index 5592238..9c50836 100644
--- a/src/edu/internet2/jenkins/DockerBuild.groovy
+++ b/src/edu/internet2/jenkins/DockerBuild.groovy
@@ -10,7 +10,7 @@ class DockerBuild implements Serializable {
   }
   
   def tag() {
-    env.toString()
+    env.keys.toString()
   }
   
   def imagename() {