diff --git a/lib/kafka/consumer.rb b/lib/kafka/consumer.rb
index f85ac0a..b39789f 100644
--- a/lib/kafka/consumer.rb
+++ b/lib/kafka/consumer.rb
@@ -127,13 +127,13 @@ def manage_partition_consumers(handler)
         distributed_partitions = self.class.distribute_partitions(running_instances, partitions)
         my_partitions = distributed_partitions[@instance]
 
-        logger.info "Claiming #{my_partitions.length} out of #{partitions.length} partitions."
+        logger.info "Claiming #{my_partitions&.length} out of #{partitions&.length} partitions."
 
         # based onw hat partitions we should be consuming and the partitions
         # that we already are consuming, figure out what partition consumers
         # to stop and start
-        partitions_to_stop  = @partition_consumers.keys - my_partitions
-        partitions_to_start = my_partitions - @partition_consumers.keys
+        partitions_to_stop  = @partition_consumers.keys - (my_partitions || [])
+        partitions_to_start = (my_partitions || []) - @partition_consumers.keys
 
         # Stop the partition consumers we should no longer be running in parallel
         if partitions_to_stop.length > 0