diff --git a/.github/workflows/spack_default_build.yaml b/.github/workflows/spack_default_build.yaml
index 66e510b..2968bc7 100644
--- a/.github/workflows/spack_default_build.yaml
+++ b/.github/workflows/spack_default_build.yaml
@@ -96,7 +96,7 @@ jobs:
       matrix:
         # Minimal Build(s) - GHCR mirror speeds these up a lot!
         spack_spec:
-          - gridkit@buildsystem
+          - gridkit@develop
 
     name: Build gridkit with Spack
     steps: