diff --git a/README.md b/README.md
index 673539b05..583d1996d 100644
--- a/README.md
+++ b/README.md
@@ -115,6 +115,8 @@ which will give you a body class like this:
 <body class="avenir bg-near-white">
 ```
 
+note: The `body_classes` parameter will not change the font used in post content. To do this, you must use the `post_content_classes` parameter.
+
 You can find a list of available typefaces [here](https://github.com/tachyons-css/tachyons/blob/v4.7.0/src/_font-family.css).
 
 And a list of background colors [here](https://github.com/tachyons-css/tachyons/blob/v4.7.0/src/_skins.css#L96).
diff --git a/layouts/_default/single.html b/layouts/_default/single.html
index a94030846..e63f129a9 100755
--- a/layouts/_default/single.html
+++ b/layouts/_default/single.html
@@ -45,7 +45,7 @@ <h1 class="f1 athelas mt3 mb1">
         <span class="f6 mv4 dib tracked"> - {{ .WordCount}} words</span>
       {{ end }}
     </header>
-    <div class="nested-copy-line-height lh-copy serif f4 nested-links nested-img mid-gray pr4-l w-two-thirds-l">
+    <div class="nested-copy-line-height lh-copy {{ $.Param "post_content_classes"  | default "serif"}} f4 nested-links nested-img mid-gray pr4-l w-two-thirds-l">
       {{- .Content -}}
       {{- partial "tags.html" . -}}
       <div class="mt6 instapaper_ignoref">
