diff --git a/src/wuttafarm/web/util.py b/src/wuttafarm/web/util.py
index 35a6f02..ec88525 100644
--- a/src/wuttafarm/web/util.py
+++ b/src/wuttafarm/web/util.py
@@ -81,7 +81,9 @@ def render_quantity_object(quantity):
     text = f"( {measure} ) {value} {unit}"
 
     if quantity["quantity_type_id"] == "material":
-        materials = ", ".join([mtype["name"] for mtype in quantity["material_types"]])
+        materials = ", ".join(
+            [mtype.get("name", "???") for mtype in quantity["material_types"]]
+        )
         return f"{materials} {text}"
 
     return text