diff --git a/.github/workflows/build-and-test.yml b/.github/workflows/build-and-test.yml
index 8d6963b..583fe06 100644
--- a/.github/workflows/build-and-test.yml
+++ b/.github/workflows/build-and-test.yml
@@ -35,5 +35,6 @@ jobs:
           curl -fsSL "$ELASTICSEARCH_URL/_cat/health?h=status"
       - name: Run tests
         env:
+          INDEX_CHUNK_SIZE: 100
           ELASTICSEARCH_URL: http://localhost:${{ job.services.elasticsearch.ports[9200] }}
         run: npm test -- --forceExit
diff --git a/src/commands/__tests__/index.integration.ts b/src/commands/__tests__/index.integration.ts
index 573f356..296e522 100644
--- a/src/commands/__tests__/index.integration.ts
+++ b/src/commands/__tests__/index.integration.ts
@@ -61,8 +61,6 @@ describe("Perform indexation", () => {
         }
       }
     };
-    // wait for the ES refresh cycle of 1sec
-    await new Promise(resolve => setTimeout(resolve, 1000));
 
     await elasticSearchClient.search(searchRequest).then(r => {
       if (r.body.timed_out) {
@@ -97,8 +95,6 @@ describe("Perform indexation", () => {
         }
       }
     };
-    // wait for the ES refresh cycle of 1sec
-    await new Promise(resolve => setTimeout(resolve, 1000));
 
     await elasticSearchClient.search(searchRequest).then(r => {
       if (r.body.timed_out) {
diff --git a/src/indexation/__tests__/bulkIndex.test.ts b/src/indexation/__tests__/bulkIndex.test.ts
index 830706c..9e9ae3e 100644
--- a/src/indexation/__tests__/bulkIndex.test.ts
+++ b/src/indexation/__tests__/bulkIndex.test.ts
@@ -24,26 +24,16 @@ describe("bulkIndexByChunks", () => {
     dataFormatterFn: dataFormatterFnMock
   };
   const indexNameMock = "test_index";
-  const CHUNK_SIZE = 100;
+  const CHUNK_SIZE = parseInt(`${process.env.INDEX_CHUNK_SIZE}`, 10) || 100;
 
   beforeEach(() => {
     process.env.TD_SIRENE_INDEX_MAX_CONCURRENT_REQUESTS = "1";
-    process.env.INDEX_CHUNK_SIZE = `${CHUNK_SIZE}`;
     esClientMock.mockReset();
     dataFormatterFnMock.mockReset();
     esClientMock.mockImplementation(() => Promise.resolve());
     dataFormatterFnMock.mockImplementation((body, _) => Promise.resolve(body));
   });
 
-  test("Should immediately send a request if body size is less than CHUNK_SIZE", async () => {
-    // One document to index
-    const bodyMock: ElasticBulkNonFlatPayload = [
-      [{ index: { _index: indexNameMock } }, { field: "value1" }]
-    ];
-    await bulkIndexByChunks(bodyMock, indexConfigMock, indexNameMock);
-    expect(esClientMock).toHaveBeenCalledTimes(1);
-  });
-
   test("Should slice the body into chunks and send each as a separate request", async () => {
     // One Chunk + 1
     const bodyMock: ElasticBulkNonFlatPayload = Array(CHUNK_SIZE + 1)
@@ -72,10 +62,12 @@ describe("bulkIndexByChunks", () => {
   });
 
   test("Should call dataFormatterFn if it is a function", async () => {
-    // One document to index
-    const bodyMock: ElasticBulkNonFlatPayload = [
-      [{ index: { _index: indexNameMock } }, { my_document_field: "value1" }]
-    ];
+    const bodyMock: ElasticBulkNonFlatPayload = Array(CHUNK_SIZE + 1)
+      .fill(0)
+      .map((_, i) => [
+        { index: { _id: `${i}`, _index: indexNameMock } },
+        { my_document_field: `value${i}` }
+      ]);
     await bulkIndexByChunks(bodyMock, indexConfigMock, indexNameMock);
     expect(indexConfigMock.dataFormatterFn).toHaveBeenCalled();
   });
diff --git a/src/indexation/elasticSearch.helpers.ts b/src/indexation/elasticSearch.helpers.ts
index 3cab783..9bb9650 100644
--- a/src/indexation/elasticSearch.helpers.ts
+++ b/src/indexation/elasticSearch.helpers.ts
@@ -308,6 +308,13 @@ export const bulkIndexByChunks = async (
   bodyBuffer = [];
 };
 
+export const flushBuffer = async (
+  indexConfig: IndexProcessConfig,
+  indexName: string
+) => {
+  await request(indexName, indexConfig, bodyBuffer);
+};
+
 /**
  * Writable stream that parses CSV to an ES bulk body
  */
@@ -355,6 +362,11 @@ const getWritableParserAndIndexer = (
       )
         .then(() => next())
         .catch(err => next(err));
+    },
+    final: async callback => {
+      // Because we buffer chunks, we need to flush it at the end
+      await flushBuffer(indexConfig, indexName);
+      callback();
     }
   });