diff --git a/app/models/metadata_document_date.rb b/app/models/metadata_document_date.rb
index bd46c5a..f49aaa7 100644
--- a/app/models/metadata_document_date.rb
+++ b/app/models/metadata_document_date.rb
@@ -10,13 +10,12 @@ class MetadataDocumentDate < MetadataTemplate
   # El valor puede ser un Date, Time o una String en el formato
   # "yyyy-mm-dd"
   def value
-    return self[:value] if self[:value].is_a? Date
-    return self[:value] if self[:value].is_a? Time
+    return self[:value] = document.date || default_value if self[:value].nil?
 
-    begin
-      self[:value] = Date.parse(self[:value]).to_time
-    rescue ArgumentError, TypeError
-      document.date || default_value
+    if self[:value].is_a? String
+      self[:value] = Date.iso8601(self[:value]).to_time
     end
+
+    self[:value]
   end
 end