diff --git a/src/cooling_wrapper.c b/src/cooling_wrapper.c
index 49d6592c4cb9d4f63a61633e21f8dbedbc7379e8..59fd431e911caf87677e2ea826e6d3f30ec3f235 100644
--- a/src/cooling_wrapper.c
+++ b/src/cooling_wrapper.c
@@ -99,6 +99,10 @@ PyArrayObject* pycooling_rate(PyObject* self, PyObject* args) {
 
   struct part p;
 
+#ifdef COOLING_GRACKLE
+  grackle_data = &cooling->chemistry;
+#endif
+
   /* return object */
   PyArrayObject *rate = PyArray_NewLikeArray(energy, NPY_ANYORDER, NULL, 1);