diff --git a/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2 b/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2
index 5206dce3f..bf2a359f5 100644
--- a/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2
+++ b/roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2
@@ -813,8 +813,8 @@ caches:
   sync_response_cache_duration: {{ matrix_synapse_caches_sync_response_cache_duration | to_json }}
 
   cache_autotuning:
-    max_cache_memory_usage: {{ matrix_synapse_cache_autotuning_max_cache_memory_usage | to_json }}
-    target_cache_memory_usage: {{ matrix_synapse_cache_autotuning_target_cache_memory_usage | to_json }}
+    max_cache_memory_usage: {{ ((matrix_synapse_cache_autotuning_max_cache_memory_usage | int | to_json) if matrix_synapse_cache_autotuning_max_cache_memory_usage else '') }}
+    target_cache_memory_usage: {{ ((matrix_synapse_cache_autotuning_target_cache_memory_usage | int | to_json) if matrix_synapse_cache_autotuning_target_cache_memory_usage else '') }}
     min_cache_ttl: {{ matrix_synapse_cache_autotuning_min_cache_ttl | to_json }}