diff --git a/lib/core/options.js b/lib/core/options.js
index f64c9b39fb..2d58aabd3a 100755
--- a/lib/core/options.js
+++ b/lib/core/options.js
@@ -107,7 +107,7 @@ export const defaultOptions = {
     vendor: [],
     plugins: [],
     babel: {},
-    postcss: [],
+    postcss: undefined,
     templates: [],
     watch: [],
     devMiddleware: {},