diff --git a/Library/Homebrew/tap.rb b/Library/Homebrew/tap.rb
index e386db7b84..66aa101589 100644
--- a/Library/Homebrew/tap.rb
+++ b/Library/Homebrew/tap.rb
@@ -527,7 +527,7 @@ end
 # A specialized {Tap} class for the core formulae
 class CoreTap < Tap
   def default_remote
-    if OS.mac? || ENV["$HOMEBREW_FORCE_HOMEBREW_ORG"]
+    if OS.mac? || ENV["HOMEBREW_FORCE_HOMEBREW_ORG"]
       "https://github.com/Homebrew/homebrew-core".freeze
     else
       "https://github.com/Linuxbrew/homebrew-core".freeze