diff --git a/lib/config/config.js b/lib/config/config.js
index 397387f..a1387f3 100644
--- a/lib/config/config.js
+++ b/lib/config/config.js
@@ -190,7 +190,7 @@ module.exports = function(options) {
     var topic = _.find(_config.topology.topics, function(t) {
       return t.name === topicName;
     });
-    assert(topic);
+    assert(topic, 'Could not find topic ['+topicName+'] in ' + JSON.stringify(_config.topology.topics));
 
     slot(group, topic, 0, function(err, result) {
       if (err) { return cb(err); }