Buttermilk is a type of milk that comes from two different processes.  The original version or traditional way of producing buttermilk is through the churning of butter.  In this original process, days may pass before the skimming of fresh milk will yield butter.  Once the butter is removed, the leftover milk will be collected and this was known as the original source of buttermilk.  Being part of the butter churning process, buttermilk, or leftover milk from butter is expected to be sour in taste.  This type of milk may be served instantly or could be mixed with other food items.

The other process of producing buttermilk is through fermentation.  Modern buttermilk is typically made from the fermentation of milk. This modern process involves the adding of bacteria culture to whole milk, skim milk, or even non-fat milk.  These bacteria will then react with the milk for several hours.  The process of fermentation typically lasts for up to 12 hours.  Once the process is completed, new buttermilk will be produced. This newer form of buttermilk is also referred to as cultured buttermilk.  Most buttermilk that are available in grocery stores today are sourced from the fermentation process rather than the traditional way of butter churning.

Some people like to drink buttermilk because of its sour and tangy flavor.  For people who prefer sweet or bland flavors, buttermilk may not be the best type of milk for them.  Some people also complain that plain buttermilk tastes like yogurt.   With its tangy flavor, most people like to drink buttermilk when it is chilled and cold.  Despite its sour taste, buttermilk is a popular ingredient in making cookie and pastry products.  Some people even prefer the sour texture it provides to the commonly sweet biscuit or cookie for example.  Health enthusiasts also like buttermilk because of its healthy bacteria content which is considered good for digestion and stomach health.