diff --git a/Readme.pod b/Readme.pod
index a587374..35f643e 100644
--- a/Readme.pod
+++ b/Readme.pod
@@ -293,6 +293,11 @@
 Activate minimal debugging.
 Defaults to C<false>.
 
+=item B<KORAPXMLTEI_TOKENIZER_HEAP_SIZE>
+
+Set the heap size for the tokenizer process.
+Defaults to C<512m>.
+
 =back
 
 =head1 COPYRIGHT AND LICENSE