diff --git a/Library/Homebrew/formula_installer.rb b/Library/Homebrew/formula_installer.rb
index 2b064107b2..63b7fa0dfb 100644
--- a/Library/Homebrew/formula_installer.rb
+++ b/Library/Homebrew/formula_installer.rb
@@ -241,7 +241,7 @@ class FormulaInstaller
 
   def install_requirement_default_formula?(req, build)
     return false unless req.default_formula?
-    return false if build.without?(req)
+    return false if build.without?(req) && (req.recommended? || req.optional?)
     return true unless req.satisfied?
     pour_bottle? || build_bottle?
   end