diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 9782fffa2d..3f09b14e30 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -546,6 +546,8 @@ class Formula
       Homebrew.dump_build_config(log)
       raise BuildError.new(self, cmd, args)
     end
+  ensure
+    log.close if log && !log.closed?
   end
 
   private