diff --git a/CHANGELOG.md b/CHANGELOG.md
index 648b2794..a3d74544 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,7 @@ Version 81:
 
 * Pass string_view by value
 * better is_final on empty_base_optimization
+* Suppress incorrect GCC warning
 
 --------------------------------------------------------------------------------
 
diff --git a/include/beast/zlib/detail/deflate_stream.hpp b/include/beast/zlib/detail/deflate_stream.hpp
index b51baff1..e0574c98 100644
--- a/include/beast/zlib/detail/deflate_stream.hpp
+++ b/include/beast/zlib/detail/deflate_stream.hpp
@@ -1040,7 +1040,10 @@ doWrite(z_params& zs, boost::optional<Flush> flush, error_code& ec)
     }
 
     // value of flush param for previous deflate call
-    boost::optional<Flush> old_flush = last_flush_;
+    auto old_flush = boost::make_optional<Flush>(
+        last_flush_.is_initialized(),
+        last_flush_ ? *last_flush_ : Flush::none);
+
     last_flush_ = flush;
 
     // Flush as much pending output as possible