diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 504fc5948e4f6fbe5032304355f4a4ae1f00b4c8..542d9df5512176037d5602266d177978c37f59d6 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -28,7 +28,7 @@ before_script:
   - cd ..
 
 # compile pyswiftsim
-  - python3 setup.py install --with-swift $LHOME/swiftsim --user
+  - python3 setup.py install --with-swift $LHOME/swiftsim --with-grackle $GRACKLE_ROOT --user
 
 # compile the docs
   - cd docs