diff --git a/packages/crafty-preset-postcss/src/index.js b/packages/crafty-preset-postcss/src/index.js
index <HASH>..<HASH> 100755
--- a/packages/crafty-preset-postcss/src/index.js
+++ b/packages/crafty-preset-postcss/src/index.js
@@ -165,7 +165,7 @@ module.exports = {
       .loader(require.resolve("css-loader"))
       .options({
         importLoaders: 1,
-        sourceMap: crafty.getEnvironment() === "production" && bundle.extractCSS
+        sourceMap: crafty.getEnvironment() === "production" && !!bundle.extractCSS
       });
 
     styleRule
crafty-preset-postcss: fix css-loader options - ensure that 'sourceMap' is always boolean