diff --git a/system/src/Grav/Common/Cache.php b/system/src/Grav/Common/Cache.php
index f2135ac70..0445c502b 100644
--- a/system/src/Grav/Common/Cache.php
+++ b/system/src/Grav/Common/Cache.php
@@ -102,7 +102,7 @@ class Cache extends Getters
         $this->enabled = (bool) $this->config->get('system.cache.enabled');
 
         // Cache key allows us to invalidate all cache on configuration changes.
-        $this->key = substr(md5(($prefix ? $prefix : 'g') . $uri->rootUrl(true) . $this->config->key() . GRAV_VERSION), 2, 8);
+        $this->key = ($prefix ? $prefix : 'g') . '-' . substr(md5($uri->rootUrl(true) . $this->config->key() . GRAV_VERSION), 2, 8);
 
         $this->driver = $this->getCacheDriver();