diff --git a/lib/ensembl.rb b/lib/ensembl.rb
index 9ad3c23..c234f8b 100644
--- a/lib/ensembl.rb
+++ b/lib/ensembl.rb
@@ -19,11 +19,13 @@ class Session
     attr_accessor :coord_system_ids #map CS id to CS name
     attr_accessor :seq_regions
     attr_accessor :collection_species
+    attr_accessor :release
 
     def initialize
       @coord_systems = Hash.new # key = id; value = CoordSystem object
       @coord_system_ids = Hash.new # key = id; value = name
       @seq_regions = Hash.new
+      @release = ENSEMBL_RELEASE
     end
     
     def reset