diff --git a/graphene_sqlalchemy/converter.py b/graphene_sqlalchemy/converter.py
index 4822f4d..de1bfde 100644
--- a/graphene_sqlalchemy/converter.py
+++ b/graphene_sqlalchemy/converter.py
@@ -247,8 +247,9 @@ def convert_sqlalchemy_type(
         return type_arg
 
     # No valid type found, warn and fall back to graphene.String
-    raise Exception(
-        "Don't know how to convert the SQLAlchemy field %s (%s, %s)"
+    raise TypeError(
+        "Don't know how to convert the SQLAlchemy field %s (%s, %s). "
+        "Please add a type converter or set the type manually using ORMField(type_=your_type)"
         % (column, column.__class__ or "no column provided", type_arg)
     )
 
@@ -562,6 +563,12 @@ def convert_sqlalchemy_hybrid_property_bare_str(type_arg: str, **kwargs):
 
 def convert_hybrid_property_return_type(hybrid_prop):
     # Grab the original method's return type annotations from inside the hybrid property
-    return_type_annotation = hybrid_prop.fget.__annotations__.get("return", str)
+    return_type_annotation = hybrid_prop.fget.__annotations__.get("return", None)
+    if not return_type_annotation:
+        raise TypeError(
+            "Cannot convert hybrid property type {} to a valid graphene type. "
+            "Please make sure to annotate the return type of the hybrid property or use the "
+            "type_ attribute of ORMField to set the type.".format(hybrid_prop)
+        )
 
     return convert_sqlalchemy_type(return_type_annotation)
diff --git a/graphene_sqlalchemy/tests/models.py b/graphene_sqlalchemy/tests/models.py
index d02ee27..9531aaa 100644
--- a/graphene_sqlalchemy/tests/models.py
+++ b/graphene_sqlalchemy/tests/models.py
@@ -88,12 +88,12 @@ class Reporter(Base):
     favorite_article = relationship("Article", uselist=False, lazy="selectin")
 
     @hybrid_property
-    def hybrid_prop_with_doc(self):
+    def hybrid_prop_with_doc(self) -> str:
         """Docstring test"""
         return self.first_name
 
     @hybrid_property
-    def hybrid_prop(self):
+    def hybrid_prop(self) -> str:
         return self.first_name
 
     @hybrid_property
@@ -253,13 +253,6 @@ def hybrid_prop_first_shopping_cart_item(self) -> ShoppingCartItem:
     def hybrid_prop_shopping_cart_item_list(self) -> List[ShoppingCartItem]:
         return [ShoppingCartItem(id=1), ShoppingCartItem(id=2)]
 
-    # Unsupported Type
-    # fixme move this somewhere else
-    #
-    # @hybrid_property
-    # def hybrid_prop_unsupported_type_tuple(self) -> Tuple[str, str]:
-    #     return "this will actually", "be a string"
-
     # Self-references
 
     @hybrid_property
diff --git a/graphene_sqlalchemy/tests/test_converter.py b/graphene_sqlalchemy/tests/test_converter.py
index 49a4d93..671c4f9 100644
--- a/graphene_sqlalchemy/tests/test_converter.py
+++ b/graphene_sqlalchemy/tests/test_converter.py
@@ -1,6 +1,6 @@
 import enum
 import sys
-from typing import Dict, Union
+from typing import Dict, Tuple, Union
 
 import pytest
 import sqlalchemy_utils as sqa_utils
@@ -79,6 +79,30 @@ def prop_method() -> int:
     assert get_hybrid_property_type(prop_method).type == graphene.Int
 
 
+def test_hybrid_unknown_annotation():
+    @hybrid_property
+    def hybrid_prop(self):
+        return "This should fail"
+
+    with pytest.raises(
+        TypeError,
+        match=r"(.*)Please make sure to annotate the return type of the hybrid property or use the "
+        "type_ attribute of ORMField to set the type.(.*)",
+    ):
+        get_hybrid_property_type(hybrid_prop)
+
+
+def test_hybrid_prop_no_type_annotation():
+    @hybrid_property
+    def hybrid_prop(self) -> Tuple[str, str]:
+        return "This should Fail because", "we don't support Tuples in GQL"
+
+    with pytest.raises(
+        TypeError, match=r"(.*)Don't know how to convert the SQLAlchemy field(.*)"
+    ):
+        get_hybrid_property_type(hybrid_prop)
+
+
 @pytest.mark.skipif(
     sys.version_info < (3, 10), reason="|-Style Unions are unsupported in python < 3.10"
 )