diff --git a/Library/Homebrew/formulary.rb b/Library/Homebrew/formulary.rb
index b01973fab6..8df05b8287 100644
--- a/Library/Homebrew/formulary.rb
+++ b/Library/Homebrew/formulary.rb
@@ -279,6 +279,8 @@ module Formulary
     end
 
     def load_file
+      tap.install unless tap.installed?
+
       super
     rescue MethodDeprecatedError => e
       e.issues_url = tap.issues_url || tap.to_s
diff --git a/Library/Homebrew/test/formulary_spec.rb b/Library/Homebrew/test/formulary_spec.rb
index 157b608050..71c6c610e1 100644
--- a/Library/Homebrew/test/formulary_spec.rb
+++ b/Library/Homebrew/test/formulary_spec.rb
@@ -227,7 +227,8 @@ describe Formulary do
       end
     end
 
-    it "raises an error if the Formula is not available" do
+    it "raises an error if the Formula is not available after tapping" do
+      expect_any_instance_of(Tap).to receive(:install)
       expect {
         described_class.to_rack("a/b/#{formula_name}")
       }.to raise_error(TapFormulaUnavailableError)