diff --git a/Library/Homebrew/cask/cmd/upgrade.rb b/Library/Homebrew/cask/cmd/upgrade.rb
index 3cf457bb29..e0c0aad719 100644
--- a/Library/Homebrew/cask/cmd/upgrade.rb
+++ b/Library/Homebrew/cask/cmd/upgrade.rb
@@ -203,7 +203,9 @@ module Cask
           # Start new cask's installation steps
           new_cask_installer.check_conflicts
 
-          puts new_cask_installer.caveats if new_cask_installer.caveats
+          if (caveats = new_cask_installer.caveats)
+            puts caveats
+          end
 
           new_cask_installer.fetch