diff --git a/lib/contentTypeParser.js b/lib/contentTypeParser.js
index b32cc09880..d4eb906b48 100644
--- a/lib/contentTypeParser.js
+++ b/lib/contentTypeParser.js
@@ -70,6 +70,7 @@ ContentTypeParser.prototype.add = function (contentType, opts, parserFn) {
     if (contentTypeIsString) {
       this.parserList.unshift(new ParserListItem(contentType))
     } else {
+      contentType.isEssence = contentType.source.indexOf(';') === -1
       this.parserRegExpList.unshift(contentType)
     }
     this.customParsers.set(contentType.toString(), parser)
@@ -389,7 +390,7 @@ function compareContentType (contentType, parserListItem) {
 }
 
 function compareRegExpContentType (contentType, essenceMIMEType, regexp) {
-  if (regexp.source.indexOf(';') === -1) {
+  if (regexp.isEssence) {
     // we do essence check
     return regexp.test(essenceMIMEType)
   } else {