diff --git a/lib/galaxy/model/custom_types.py b/lib/galaxy/model/custom_types.py
index 408eac2442c..f537a93f463 100644
--- a/lib/galaxy/model/custom_types.py
+++ b/lib/galaxy/model/custom_types.py
@@ -2,6 +2,7 @@ from sqlalchemy.types import *
 import simplejson
 import pickle
 from galaxy.util.bunch import Bunch
+from galaxy.util.aliaspickler import AliasPickleModule
 
 class JSONType( TypeDecorator ):
     """ 
@@ -41,13 +42,17 @@ class JSONType( TypeDecorator ):
     def is_mutable( self ):
         return self.mutable
 
+MetadataPickler = AliasPickleModule( {
+    ( "cookbook.patterns", "Bunch" ) : ( "galaxy.util.bunch" , "Bunch" )
+} )
+
 class MetadataType( JSONType ):
     """
     Mixture between JSONType and PickleType...can read in either, and
     writes JSON.
     """
 
-    def __init__( self, pickler=None, jsonifyer=None, mutable=True ):
+    def __init__( self, pickler=MetadataPickler, jsonifyer=None, mutable=True ):
         self.jsonifyer =  jsonifyer or simplejson
         self.pickler = pickler or pickle
         self.mutable = mutable
diff --git a/lib/galaxy/model/mapping.py b/lib/galaxy/model/mapping.py
index 5de3ee2c74a..bfbed5553ff 100644
--- a/lib/galaxy/model/mapping.py
+++ b/lib/galaxy/model/mapping.py
@@ -20,11 +20,6 @@ from sqlalchemy import *
 from galaxy.model import *
 from galaxy.model.custom_types import *
 from galaxy.util.bunch import Bunch
-from galaxy.util.aliaspickler import AliasPickleModule
-
-MetaPickler = AliasPickleModule( {
-    ("cookbook.patterns","Bunch"):("galaxy.util.bunch","Bunch")
-    } )
 
 metadata = DynamicMetaData( threadlocal=False )
 context = SessionContext( create_session ) 
@@ -68,7 +63,7 @@ Dataset.table = Table( "dataset", metadata,
     Column( "extension", TrimmedString( 64 ) ),
     Column( "dbkey", TrimmedString( 64 ), key="old_dbkey" ), # maps to old_dbkey, see __init__.py
     Column( "state", TrimmedString( 64 ) ),
-    Column( "metadata", MetadataType(pickler=MetaPickler), key="_metadata" ),
+    Column( "metadata", MetadataType(), key="_metadata" ),
     Column( "parent_id", Integer, nullable=True ),
     Column( "designation", TrimmedString( 255 ) ),
     Column( "deleted", Boolean ),