diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 158e7f017b..b814eeabc6 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -100,6 +100,7 @@ class Formula
   include FileUtils
 
   attr_reader :name, :path, :url, :version, :homepage, :specs, :downloader
+  attr_reader :stable, :unstable
   attr_reader :bottle, :bottle_sha1, :head
 
   # Homebrew determines the name