diff --git a/sumpy/kernel.py b/sumpy/kernel.py
index 15ad22a522981d196e6dcaccb81ed22a4f0d2d7f..40e82dc72af28830e548e42d1d8e1d6d9e77c9c1 100644
--- a/sumpy/kernel.py
+++ b/sumpy/kernel.py
@@ -357,7 +357,7 @@ class ExpressionKernel(Kernel):
     def update_persistent_hash(self, key_hash, key_builder):
         key_hash.update(type(self).__name__.encode("utf8"))
         for name, value in zip(self.init_arg_names, self.__getinitargs__()):
-            if name in ["expression", "scaling"]:
+            if name in ["expression", "global_scaling_const"]:
                 from pymbolic.mapper.persistent_hash import (
                         PersistentHashWalkMapper as PersistentHashWalkMapper)
                 PersistentHashWalkMapper(key_hash)(value)