diff --git a/roles/matrix-synapse/defaults/main.yml b/roles/matrix-synapse/defaults/main.yml
index 496d911b0..7384939fb 100644
--- a/roles/matrix-synapse/defaults/main.yml
+++ b/roles/matrix-synapse/defaults/main.yml
@@ -597,15 +597,15 @@ matrix_synapse_media_storage_provider_s3_threadpool_size: "20"
 
 matrix_synapse_media_storage_provider_s3_config: "{{ matrix_synapse_media_storage_provider_s3_config_yaml|from_yaml }}"
 matrix_synapse_media_storage_provider_s3_config_yaml: |
-  "bucket": {{ matrix_synapse_media_storage_provider_s3_bucket|to_json }},
+  bucket: {{ matrix_synapse_media_storage_provider_s3_bucket|to_json }}
   # All of the below options are optional, for use with non-AWS S3-like
   # services, or to specify access tokens here instead of some external method.
-  "region_name": {{ matrix_synapse_media_storage_provider_s3_region_name|to_json }},
-  "endpoint_url": {{ matrix_synapse_media_storage_provider_s3_endpoint_url|to_json }},
-  "access_key_id": {{ matrix_synapse_media_storage_provider_s3_access_key_id|to_json }},
-  "secret_access_key": {{ matrix_synapse_media_storage_provider_s3_secret_access_key|to_json }},
-  "storage_class": {{ matrix_synapse_media_storage_provider_s3_storage_class|to_json }},
-  "threadpool_size": {{ matrix_synapse_media_storage_provider_s3_threadpool_size }}
+  region_name: {{ matrix_synapse_media_storage_provider_s3_region_name|to_json }}
+  endpoint_url: {{ matrix_synapse_media_storage_provider_s3_endpoint_url|to_json }}
+  access_key_id: {{ matrix_synapse_media_storage_provider_s3_access_key_id|to_json }}
+  secret_access_key: {{ matrix_synapse_media_storage_provider_s3_secret_access_key|to_json }}
+  storage_class: {{ matrix_synapse_media_storage_provider_s3_storage_class|to_json }}
+  threadpool_size: {{ matrix_synapse_media_storage_provider_s3_threadpool_size }}
 
 # Goofys S3 Integration
 matrix_s3_media_store_enabled: false