diff --git a/pydropsonde/processor.py b/pydropsonde/processor.py
index 5fad4b07..f6d273e4 100644
--- a/pydropsonde/processor.py
+++ b/pydropsonde/processor.py
@@ -1496,7 +1496,7 @@ def make_attr_coordinates(self):
         self.interim_l3_ds = ds.assign_coords(new_coords)
         return self
 
-    def add_qc_to_interim_l3(self, keep=["sonde_qc"]):
+    def add_qc_to_interim_l3(self, keep=None):
         """
         Add quality control flags to the interim Level 3 dataset.