diff --git a/src/workflows/util/zocalo/configuration.py b/src/workflows/util/zocalo/configuration.py
index 01ae7e4..9ba8ec6 100644
--- a/src/workflows/util/zocalo/configuration.py
+++ b/src/workflows/util/zocalo/configuration.py
@@ -68,7 +68,7 @@ class Pika:
 
     class Schema(PluginSchema):
         host = fields.Str(required=True)
-        port = fields.Field(required=True)
+        port = fields.Raw(required=True)
         username = fields.Str(required=True)
         password = fields.Str(required=True)
         vhost = fields.Str(required=True)