Ensure that the custom_teaser column exists before trying to use it incase the migration hasn't been generated/run.

app/helpers/blog_posts_helper.rb

@@ -43,14 +43,13 @@ module BlogPostsHelper
   end
 
   def blog_post_teaser(post)
-    if post.custom_teaser.present?
+    if post.respond_to?(:custom_teaser) && post.custom_teaser.present?
      post.custom_teaser.html_safe
     else
-     truncate(
-       post.body,
+     truncate(post.body, {
        :length => RefinerySetting.find_or_set(:blog_post_teaser_length, 250),
        :preserve_html_tags => true
-      ).html_safe
+      }).html_safe
     end
   end
 end