diff --git a/Library/brew.rb b/Library/brew.rb
index 38e11473c4..839ab6e363 100644
--- a/Library/brew.rb
+++ b/Library/brew.rb
@@ -104,7 +104,7 @@ begin
         tap_commands += %W[/usr/bin/sudo -u ##{brew_uid}]
       end
       tap_commands += %W[#{HOMEBREW_BREW_FILE} tap #{possible_tap}]
-      safe_system *tap_commands
+      safe_system(*tap_commands)
       exec HOMEBREW_BREW_FILE, cmd, *ARGV
     else
       onoe "Unknown command: #{cmd}"