diff --git a/esm-collections/disk-access/dkrz_era5_disk.json b/esm-collections/disk-access/dkrz_era5_disk.json
index c061248883d753a96404be7ee82817dc0045e6cf..0ecb88d602d0a3bb9266b2be7ae06104e65e1622 100755
--- a/esm-collections/disk-access/dkrz_era5_disk.json
+++ b/esm-collections/disk-access/dkrz_era5_disk.json
@@ -100,6 +100,7 @@
            "type": "union"}],
     "variable_column_name": "short_name",
     "groupby_attrs": [
+      "era_id",
       "table_id",
       "stepType",
       "level_type",