diff --git a/config/consumer.yml b/config/consumer.yml
index 9524fd7..97d7e8e 100644
--- a/config/consumer.yml
+++ b/config/consumer.yml
@@ -3,6 +3,7 @@ testMode: false
 defaults:
   mode: fk
   flushInterval: 5000
+  amqpPrefetch: 100
 amqp: amqp://user:password@localhost:5672
 db: 
   host: localhost
diff --git a/lib/queue-fk.js b/lib/queue-fk.js
index 5d22d2f..d24b92c 100644
--- a/lib/queue-fk.js
+++ b/lib/queue-fk.js
@@ -30,7 +30,7 @@ module.exports = class QueueFk extends Queue {
     const {messages} = this;
 
     if (messages.length) {
-      const {consumer, scopes} = this;
+      const {consumer, scopes, channel} = this;
       this.reset();
       
       if (consumer.conf.debug)
@@ -49,19 +49,21 @@ module.exports = class QueueFk extends Queue {
           }
         }
 
-        for (const message of messages)
-          await this.channel.ack(message);
+        const promises = [];
+        for (const msg of messages)
+          promises.push(channel.ack(msg));
+        await Promise.all(promises);
       } catch(err) {
-        for (const message of messages)
-          await this.channel.nack(message);
-        console.error(err);
+        for (const msg of messages)
+          await channel.nack(msg);
+        throw err;
       }
     }
 
     this.flush(this.conf.flushInterval);
   }
 
-  async onConsume(msg) {
+  onConsume(msg) {
     const {conf} = this;
     const consumer = this.consumer;
     const data = JSON.parse(msg.content.toString());
@@ -86,7 +88,7 @@ module.exports = class QueueFk extends Queue {
         ids.add(row[key]);
 
     this.messages.push(msg);
-    if (this.messages.length == consumer.conf.amqpPrefetch)
+    if (this.messages.length == conf.amqpPrefetch)
       this.flush();
   }
 }
diff --git a/package.json b/package.json
index ecc4094..fa89ccd 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "mycdc",
-  "version": "0.0.12",
+  "version": "0.0.13",
   "author": "Verdnatura Levante SL",
   "description": "Asynchronous DB calculations reading the binary log",
   "license": "GPL-3.0",