diff --git a/Jenkinsfile b/Jenkinsfile
index 9fd52dc..906d03e 100644
--- a/Jenkinsfile
+++ b/Jenkinsfile
@@ -8,17 +8,17 @@ pipeline {
 
     stages {
         stage('Chibi primitives') {
-            environment { SCHEME=chibi }
+            environment { SCHEME="chibi" }
             agent { dockerfile { filename 'Dockerfile.test'; additionalBuildArgs '--build-arg COMPILE_R7RS=${env.SCHEME}' } }
             steps { catchError(buildResult: 'SUCCESS', stageResult: 'FAILURE') { sh 'make test-compile-r7rs COMPILE_R7RS=${env.SCHEME} TESTNAME=primitives' } }
         }
         stage('Chibi addressof') {
-            environment { SCHEME=chibi }
+            environment { SCHEME="chibi" }
             agent { dockerfile { filename 'Dockerfile.test'; additionalBuildArgs '--build-arg COMPILE_R7RS=${env.SCHEME}' } }
             steps { catchError(buildResult: 'SUCCESS', stageResult: 'FAILURE') { sh 'make test-compile-r7rs COMPILE_R7RS=${env.SCHEME} TESTNAME=addressof' } }
         }
         stage('Chibi callback') {
-            environment { SCHEME=chibi }
+            environment { SCHEME="chibi" }
             agent { dockerfile { filename 'Dockerfile.test'; additionalBuildArgs '--build-arg COMPILE_R7RS=${env.SCHEME}' } }
             steps { catchError(buildResult: 'SUCCESS', stageResult: 'FAILURE') { sh 'make test-compile-r7rs COMPILE_R7RS=${env.SCHEME} TESTNAME=callback' } }
         }