diff --git a/minify.php b/minify.php
index 85553d2..d03ffc9 100644
--- a/minify.php
+++ b/minify.php
@@ -299,7 +299,7 @@ class Minify {
   public function combine($minify = true) {
     // Return contents from server cache if possible.
     if (MINIFY_USE_CACHE) {
-      if ($cacheResult = $this->serverCache()) {
+      if ($cacheResult = $this->serverCache(true)) {
         return $cacheResult;
       }
     }