diff --git a/operations/mimir/config.libsonnet b/operations/mimir/config.libsonnet
index 6369513cd63..f52b38d954f 100644
--- a/operations/mimir/config.libsonnet
+++ b/operations/mimir/config.libsonnet
@@ -358,7 +358,7 @@
         ruler_max_rule_groups_per_tenant: 20,
 
         // No retention for now.
-        compactor_blocks_retention_period: 0,
+        compactor_blocks_retention_period: '0',
       },
 
       medium_small_user:: {