diff --git a/src/Plugin/search_api/processor/AddHierarchy.php b/src/Plugin/search_api/processor/AddHierarchy.php
index 3d94a5d..220c5c8 100644
--- a/src/Plugin/search_api/processor/AddHierarchy.php
+++ b/src/Plugin/search_api/processor/AddHierarchy.php
@@ -137,7 +137,7 @@ class AddHierarchy extends ProcessorPluginBase implements PluginFormInterface {
    *   Returns TRUE if the given field is an entity reference field.
    */
   protected function isEntityReferenceField(FieldInterface $field) {
-    return $field->getOriginalType() == 'field_item:entity_reference';
+    return $field->getDataDefinition()->getDataType() == 'field_item:entity_reference';
   }
 
   /**