You can control the length of text to appear for each article by restricting the number of characters to display in the body section of each post.
This will take an article that has a full body section on your feed and shorten it to the set limit. You can chose from 2 options.
1. Paragraph: Digesto will extract the first paragraph encountered in the <description> element of your rss feed.
2. Characters: Digesto will extract the X first characters and add an ellipsis at the end of this text block (...)
This allows to convert an article like this one on your blog:
And convert it into a nice excerpt on your bloc email:
To setup Max Characters on your digest, edit your Digest click on the "Advanced" section.
Use the "Max Characters" setting to set the maximum number of characters or keep only the "1st paragraph".