diff --git a/pyproject.toml b/pyproject.toml
index d2be8c5..955ec5e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -48,6 +48,11 @@ dependencies = [
         "WuttJamaican[db]>=0.28.7",
         "zope.sqlalchemy>=1.5",
 
+        # nb. this must be pinned for now, until SQLAlchemy-Utils
+        # can address a new bug that showed up in SA 2.1.0b1
+        # cf. https://github.com/kvesteri/sqlalchemy-utils/issues/800
+        "SQLAlchemy<2.1",
+
         # nb. this must be pinned for now, until pyramid can remove
         # its dependency on pkg_resources.
         # cf. https://github.com/Pylons/pyramid/issues/3731