diff --git a/src/main/resources/avro/LogRecordTopicsFlattened.avsc b/src/main/resources/avro/LogRecordTopicsFlattened.avsc
index 0751986..a07f1d7 100644
--- a/src/main/resources/avro/LogRecordTopicsFlattened.avsc
+++ b/src/main/resources/avro/LogRecordTopicsFlattened.avsc
@@ -17,22 +17,22 @@
 		{
 			"name": "topic0",
 			"type": ["null", "string"],
-			"default": ""
+			"default": null
 		},
 		{
 			"name": "topic1",
 			"type": ["null", "string"],
-			"default": ""
+			"default": null
 		},
 		{
 			"name": "topic2",
 			"type": ["null", "string"],
-			"default": ""
+			"default": null
 		},
 		{
 			"name": "topic3",
 			"type": ["null", "string"],
-			"default": ""
+			"default": null
 		},
 		{
 			"name": "transactionHash",