diff --git a/Jenkinsfile b/Jenkinsfile
index 74fc3ee..fcc1c61 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -11,7 +11,7 @@ pipeline {
         stage('Build Docker Image') {
             steps {
                 script {
-                    sh 'echo ${env.BUILD_NUMBER}'
+                    sh 'echo ${BUILD_NUMBER}'
                     def dockerImage = docker.build('git.thisfro.ch/jenkinsci/pflaenzli', '-f Dockerfile . --tag git.thisfro.ch/jenkinsci/pflaenzli:${buildNumber}')
                 }
             }