Post meta – returning the ‘class’ key

I’m trying to use post meta data for the first time and I seem to be running into some issues.

I’ve setup a post with the custom “class” key and using “normal” as a value. In my index page, I call this using the following:

<?php get_post_meta($post->ID, ‘class’, true); ?>

Unfortunately, this does not return any value. Am I doing something wrong, or did I miss a step?