diff --git a/build-aux/hydra/gnu-system.scm b/build-aux/hydra/gnu-system.scm
index 6bcfbf5dc3..06a8048f32 100644
--- a/build-aux/hydra/gnu-system.scm
+++ b/build-aux/hydra/gnu-system.scm
@@ -70,7 +70,8 @@
                          #:optional (package-derivation package-derivation))
   "Convert PACKAGE to an alist suitable for Hydra."
   `((derivation . ,(derivation-file-name
-                    (package-derivation store package system)))
+                    (package-derivation store package system
+                                        #:graft? #f)))
     (description . ,(package-synopsis package))
     (long-description . ,(package-description package))
     (license . ,(package-license package))