diff --git a/src/calibre/db/fields.py b/src/calibre/db/fields.py
index 8c6d18a74d..933a4c861c 100644
--- a/src/calibre/db/fields.py
+++ b/src/calibre/db/fields.py
@@ -31,7 +31,7 @@ class Field(object):
         self.has_text_data = dt in {'text', 'comments', 'series', 'enumeration'}
         self.table_type = self.table.table_type
         self._sort_key = (sort_key if dt in ('text', 'series', 'enumeration') else lambda x: x)
-        self._default_sort_key = ''
+        self._default_sort_key = b''
         if dt in {'int', 'float', 'rating'}:
             self._default_sort_key = 0
         elif dt == 'bool':
diff --git a/src/calibre/db/tables.py b/src/calibre/db/tables.py
index 34de470090..f71abe2a6d 100644
--- a/src/calibre/db/tables.py
+++ b/src/calibre/db/tables.py
@@ -52,16 +52,10 @@ class Table(object):
         self.name, self.metadata = name, metadata
         self.sort_alpha = metadata.get('is_multiple', False) and metadata.get('display', {}).get('sort_alpha', False)
 
-        text = lambda x:x.decode('utf-8', 'replace') if isinstance(x, bytes) else x
-
         # self.unserialize() maps values from the db to python objects
         self.unserialize = \
             {
                 'datetime': _c_convert_timestamp,
-                'text': text,
-                'comments': text,
-                'series': text,
-                'enumeration': text,
                 'bool': bool
             }.get(
                 metadata['datatype'], lambda x: x)