diff --git a/roles/matrix-synapse/templates/synapse/homeserver.yaml.j2 b/roles/matrix-synapse/templates/synapse/homeserver.yaml.j2
index 2e82ea3b6..5d7502fdd 100644
--- a/roles/matrix-synapse/templates/synapse/homeserver.yaml.j2
+++ b/roles/matrix-synapse/templates/synapse/homeserver.yaml.j2
@@ -2651,7 +2651,7 @@ spam_checker: {{ matrix_synapse_spam_checker|to_json }}
 # Note that this option will only affect rooms created after it is set. It
 # will also not affect rooms created by other servers.
 #
-encryption_enabled_by_default_for_room_type: {{ matrix_synapse_encryption_enabled_by_default_for_room_type }}
+encryption_enabled_by_default_for_room_type: {{ matrix_synapse_encryption_enabled_by_default_for_room_type|to_json }}
 
 
 # Uncomment to allow non-server-admin users to create groups on this server