diff --git a/install_spack_env.sh b/install_spack_env.sh
index ffd375298b4535db9be8f0ac0f14032204c28c43..8271e723c4349279d5805c4f88e433d147304840 100644
--- a/install_spack_env.sh
+++ b/install_spack_env.sh
@@ -79,7 +79,7 @@ spack env activate --without-view $EBRAINS_SPACK_ENV
 spack env view disable
 
 # fetch all sources
-spack --verbose concretize -j$SPACK_JOBS --force --fresh --test root
+spack --debug concretize -j$SPACK_JOBS --force --fresh --test root
 spack-python -c "exit(not len(spack.environment.active_environment().uninstalled_specs()))" && spack fetch --dependencies --missing
 
 # install the environment, use 2 jobs to reduce the amount of required RAM