diff --git a/heka/files/encoder/es-json.toml b/heka/files/encoder/es-json.toml
index c4c4659..2401198 100644
--- a/heka/files/encoder/es-json.toml
+++ b/heka/files/encoder/es-json.toml
@@ -2,7 +2,7 @@
 type = "ESJsonEncoder"
 index = "{{ values.index }}"
 
-{% if values.es_index_from_timestamp = 'True' %}
+{% if values.es_index_from_timestamp == 'True' %}
 es_index_from_timestamp = true
 {%- else -%}
 es_index_from_timestamp = false