diff --git a/src/infi/clickhouse_orm/fields.py b/src/infi/clickhouse_orm/fields.py
index dc51a57..659b8ce 100644
--- a/src/infi/clickhouse_orm/fields.py
+++ b/src/infi/clickhouse_orm/fields.py
@@ -187,7 +187,7 @@ class DateTimeField(Field):
             return dt.astimezone(pytz.utc)
         raise ValueError('Invalid value for %s - %r' % (self.__class__.__name__, value))
 
-    def to_db_string(self, value, quote=True):
+    def to_db_string(self, value, quote=False):
         return escape('%010d' % timegm(value.utctimetuple()), quote)