diff --git a/postprocessor.py b/postprocessor.py
index adcb4d7..995f2d1 100644
--- a/postprocessor.py
+++ b/postprocessor.py
@@ -1700,7 +1700,7 @@ class PostProcessor(HDF5Container):
             ),
             "mass": Rule(
                 self,
-                partial(self._sum, mass_func),
+                partial(self._sum, mass_func, mass_weighted=False),
                 "Total mass",
                 "/globals",
                 unit=self.info["unit_density"] * self.info["unit_length"] ** 3,