diff --git a/docs/reference/indices/flush.asciidoc b/docs/reference/indices/flush.asciidoc
index a0027756ab5..fdfcd80ecd4 100644
--- a/docs/reference/indices/flush.asciidoc
+++ b/docs/reference/indices/flush.asciidoc
@@ -2,11 +2,12 @@
 == Flush
 
 The flush API allows to flush one or more indices through an API. The
-flush process of an index basically frees memory from the index by
-flushing data to the index storage and clearing the internal
-<<index-modules-translog,transaction log>>. By
-default, Elasticsearch uses memory heuristics in order to automatically
-trigger flush operations as required in order to clear memory.
+flush process of an index makes sure that any data that is currently only
+persisted in the <<index-modules-translog,transaction log>> is also permanently
+persisted in Lucene. This reduces recovery times as that data doesn't need to be
+reindexed from the transaction logs after the Lucene indexed is opened. By
+default, Elasticsearch uses heuristics in order to automatically
+trigger flushes as required. It is rare for users to need to call the API directly.
 
 [source,js]
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