diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 6143a4689b..c2aeec8de3 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -557,7 +557,9 @@ private
   # For brew-fetch and others.
   def fetch
     downloader = @downloader
-    mirror_list = mirrors
+    # Don't attempt mirrors if this install is not pointed at a "stable" URL.
+    # This can happen when options like `--HEAD` are invoked.
+    mirror_list =  @spec_to_use == @stable ? mirrors : []
 
     # Ensure the cache exists
     HOMEBREW_CACHE.mkpath