Monthly subscription products are not a default setting within Shopify. In order to offer a subscription for our coffee products, you have to add an app that enables this functionality.
We would recommend using the Paywhirl app (https://apps.shopify.com/paywhirl-recurring-payments).
Our products are capable of being used with this app to offer your customers a subscription product. We are working with Paywhirl to make a detailed guide to help get this setup quickly and will update this document once it is complete.