diff --git a/eth/tracers/firehose_concurrency_test.go b/eth/tracers/firehose_concurrency_test.go
index d69291e858..691fa00931 100644
--- a/eth/tracers/firehose_concurrency_test.go
+++ b/eth/tracers/firehose_concurrency_test.go
@@ -15,6 +15,7 @@ import (
 func TestFirehose_BlockPrintsToFirehose_SingleBlock(t *testing.T) {
 
 	f := NewFirehose(&FirehoseConfig{
+		ConcurrentBlockFlushing:    true,
 		ApplyBackwardCompatibility: ptr(false),
 		private: &privateFirehoseConfig{
 			FlushToTestBuffer: true,
@@ -65,6 +66,7 @@ func TestFirehose_BlocksPrintToFirehose_MultipleBlocksInOrder(t *testing.T) {
 	const baseBlockNum = 1000
 
 	f := NewFirehose(&FirehoseConfig{
+		ConcurrentBlockFlushing:    true,
 		ApplyBackwardCompatibility: ptr(false),
 		private: &privateFirehoseConfig{
 			FlushToTestBuffer: true,