diff --git a/core/admin/mailu/models.py b/core/admin/mailu/models.py
index b4f0efa0..cb581929 100644
--- a/core/admin/mailu/models.py
+++ b/core/admin/mailu/models.py
@@ -21,6 +21,11 @@ import dns
 db = flask_sqlalchemy.SQLAlchemy()
 config = configuration.ConfigManager()
 
+def email_type():
+    if config['DB_FLAVOR'] == 'postgresql':
+        return CIText()
+    else:
+        return db.String(255, collation="NOCASE")
 
 class IdnaDomain(db.TypeDecorator):
     """ Stores a Unicode string in it's IDNA representation (ASCII only)
@@ -58,9 +63,6 @@ class IdnaEmail(db.TypeDecorator):
             idna.decode(domain_name),
         )
 
-    def __init__(self):
-        if config['DB_FLAVOR'] == 'postgresql':
-            self.impl = CIText()
 
 
 class CommaSeparatedList(db.TypeDecorator):
@@ -443,7 +445,7 @@ class Fetch(Base):
     __tablename__ = "fetch"
 
     id = db.Column(db.Integer(), primary_key=True)
-    user_email = db.Column(db.String(255), db.ForeignKey(User.email),
+    user_email = db.Column(email_type(), db.ForeignKey(User.email),
         nullable=False)
     user = db.relationship(User,
         backref=db.backref('fetches', cascade='all, delete-orphan'))