diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index f508c96dc7e59aceb416f62943911bb5c1e697a5..a273e3c1c5503722a3fd4ed30ea889e638e4947f 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -67,9 +67,6 @@ class Formula
   # @see #active_spec
   attr_reader :active_spec_sym
 
-  # The {PkgVersion} for this formula with version and {#revision} information.
-  attr_reader :pkg_version
-
   # Used for creating new Homebrew versions of software without new upstream
   # versions.
   # @see .revision
@@ -118,7 +115,6 @@ class Formula
       :stable
     end
     validate_attributes!
-    @pkg_version = PkgVersion.new(version, revision)
     @build = active_spec.build
     @pin = FormulaPin.new(self)
   end
@@ -207,6 +203,11 @@ class Formula
     active_spec.version
   end
 
+  # The {PkgVersion} for this formula with {version} and {#revision} information.
+  def pkg_version
+    PkgVersion.new(version, revision)
+  end
+
   # A named Resource for the currently active {SoftwareSpec}.
   def resource(name)
     active_spec.resource(name)