diff --git a/Library/Homebrew/bottle_version.rb b/Library/Homebrew/bottle_version.rb
index 6075f967aa..3a8f413f20 100644
--- a/Library/Homebrew/bottle_version.rb
+++ b/Library/Homebrew/bottle_version.rb
@@ -30,7 +30,7 @@ class BottleVersion < Version
     return m.captures.first unless m.nil?
 
     # e.g. 20120731 from fontforge-20120731.mavericks.bottle.tar.gz
-    m = /-(\d+)/.match(stem)
+    m = /-(\d{8})/.match(stem)
     return m.captures.first unless m.nil?
 
     super