diff --git a/Library/Homebrew/os/mac/hardware.rb b/Library/Homebrew/os/mac/hardware.rb
index 04e470b9b1..17e9ca65b4 100644
--- a/Library/Homebrew/os/mac/hardware.rb
+++ b/Library/Homebrew/os/mac/hardware.rb
@@ -135,7 +135,7 @@ module MacCPUs
     sysctl_bool('hw.optional.sse4_2')
   end
 
-  protected
+  private
 
   def sysctl_bool(key)
     sysctl_int(key) == 1