diff --git a/lib/middleman/features/minify_css.rb b/lib/middleman/features/minify_css.rb
index e019828e..e3d29224 100644
--- a/lib/middleman/features/minify_css.rb
+++ b/lib/middleman/features/minify_css.rb
@@ -2,7 +2,9 @@ module Middleman::Features::MinifyCss
   class << self
     def registered(app)
       require "middleman/features/minify_css/cssmin"
-      app.set :css_compressor, ::CSSMin
+      app.before_configuration do
+        set :css_compressor, ::CSSMin
+      end
     end
     alias :included :registered
   end