diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index dc9b680f2e..321599f06c 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -693,8 +693,8 @@ class Formula
       @skip_clean_paths ||= Set.new
     end
 
-    def keg_only reason, explanation=nil
-      @keg_only_reason = KegOnlyReason.new(reason, explanation.to_s.chomp)
+    def keg_only reason, explanation=""
+      @keg_only_reason = KegOnlyReason.new(reason, explanation)
     end
 
     # Flag for marking whether this formula needs C++ standard library
diff --git a/Library/Homebrew/formula_support.rb b/Library/Homebrew/formula_support.rb
index f3587e9a80..aa31742190 100644
--- a/Library/Homebrew/formula_support.rb
+++ b/Library/Homebrew/formula_support.rb
@@ -4,9 +4,7 @@ FormulaConflict = Struct.new(:name, :reason)
 # Used to annotate formulae that duplicate OS X provided software
 # or cause conflicts when linked in.
 class KegOnlyReason
-  attr_reader :reason, :explanation
-
-  def initialize reason, explanation=nil
+  def initialize(reason, explanation)
     @reason = reason
     @explanation = explanation
   end
@@ -38,9 +36,9 @@ class KegOnlyReason
       #{@explanation}
       EOS
     when :provided_until_xcode43
-      "Xcode provides this software prior to version 4.3.\n\n#{explanation}"
+      "Xcode provides this software prior to version 4.3.\n\n#{@explanation}"
     when :provided_until_xcode5
-      "Xcode provides this software prior to version 5.\n\n#{explanation}"
+      "Xcode provides this software prior to version 5.\n\n#{@explanation}"
     else
       @reason
     end.strip