diff --git a/Library/Homebrew/formula_creator.rb b/Library/Homebrew/formula_creator.rb
index 8a52ec8a36..0d7507938e 100644
--- a/Library/Homebrew/formula_creator.rb
+++ b/Library/Homebrew/formula_creator.rb
@@ -86,8 +86,8 @@ module Homebrew
           html_doctype_prefix = "<!doctype html"
           # Number of bytes to read from file start to ensure it is not HTML.
           # HTML may start with arbitrary number of whitespace lines.
-          head_len = 100
-          if File.read(filepath, head_len).strip.downcase.start_with?(html_doctype_prefix)
+          bytes_to_read = 100
+          if File.read(filepath, bytes_to_read).strip.downcase.start_with?(html_doctype_prefix)
             raise "Downloaded URL is not archive"
           end
 
