Linkage of Process to Historical Context (A Series): Decoction Mashing

As I sit in my office listening to the subtle harmonies of my bubbling airlocks and the Craft Beer Temple blog show, my thoughts drift to a topic for my next blog entry. Sure, I could go straight to the recipes, but as any good academic knows, one must first explore the philosophy and process of one's craft before throwing caution to the wind and jumping in sight unseen. Although I do not intend for this to be a treatise or a dissertation, I am accustomed to a style of writing in which one begins a work by preparing the reader for what said work will contain, then actually telling the reader the thing for which purpose said work has been written, and finally reviewing what thing was told to the reader in said work. This is a rather tedious style of writing (IMHO) born out of the paranoia of academics that the reader will get it wrong (and they still often do). However, it also serves many additional functions, chief among them increasing the total number of words written and pages filled. But that is not my goal, here (notice I'm not using Courier New font). Rather, I desire to establish a basis for my craft within its historical context, and provide a link to the evolution of my current process. The task of description and linkage may bloom into multiple blog entries, and/or may punctuate sequences of entries on other topics, but I recognize that it is always there in the background and its presence is perceptible through a process of fluctuating transparency.

So, this blog entry and, perhaps, several subsequent entries will review a few traditional brewing methods, and discuss the purpose of their uses (or my interpretation of their uses; I am neither a beer writer/historian nor brewing sciences expert by trade). To preface the following, it is assumed that you, the reader, are already familiar with the basic brewing terminology and process. However, if you are not, I have included some helpful links throughout the text. If questions remain, don't hesitate to ask them and I will try to help or point you in the right direction.

Today, we will cover decoction mashing. "What is decoction mashing?" you may ask and, "why do it?" Rather than casting my bait into waters that have already been over-fished, I will focus more on the "why?" than the "what?" To put it simply, decoction mashing is a process of mashing in which a portion of the mash is removed from the mashing vessel, brought to saccarification temperature, subsequently boiled, and finally returned to the mashing vessel (tun) to raise the overall mash temperature. This time consuming process may take more time than the entire brewday for an extract brewer, and should not be entered into blindly or without proper planning. Truth be told, decoction mashing is not required to produce certain beer styles, and the homebrewer can easily brew great beer without doing a decoction mash. In fact, most (if not all) modern brewing malts are produced with such excellent efficiency and are fully modified so that a simple infusion mash is all that is necessary to convert starches into sugars. "So why do it, Mr. Fermentivity blogger?"

That's a very good question, and one I hope to try to answer. Before telling why I (sometimes) do it, let's gain an understanding of its historical context and why brewers used to do it. Decoction mashing evolved in Europe before the development of modern measuring equipment (thermometers, etc.) Brewers knew that adding water to malted grain and heating it to a certain temperature range over a length of time resulted in the conversion of starches into sugars; however, they had no way to accurately measure and regulate a temperature range between 145F-160F by heating the mash tun directly. They did have two relatively constant reference points though: body temperature, and the physical characteristics of boiling water. Over time, brewers learned that heating the mash to blood temperature, removing a portion and boiling it, and returning that decocted and boiled portion back to the mash (and repeating these steps 2 or 3 times), raised the temperature of the overall mash through a series of temperature steps which resulted in a very fermentable wort. As you may have read in the past, or in some of my links, there exist some variations on the general decoction mashing process, but the result is the same: sweet, very fermentable wort. Now that we have an understanding of why decoction mashing was used within its historical context, let's explore why a homebrewer would want to do it today.

There are many reasons why a homebrewer would use a decoction mash. And you may choose to justify your use of decoction mashing (or not) with any or all of these reasons:
-It's fun to be a part of history and place oneself within a certain context.
-Details are important to you and you aren't happy unless you do it exactly right (whatever that means...).
-You want an excuse to buy more brewing equipment and use the "necessity" of decoction mashing as a way to convince SWMBO to let you.
-You look for any excuse to make your brewday as labor intensive and/or lengthy as possible so you can savor every minute.
-You appreciate the complexity of color and flavor that only a triple decoction can provide to your bohemian pilsner or doppelbock.
-There are others, I'm sure, but I'm getting tired of writing and have other things to do.

Sorry for the abrupt end. Until next time, be fermentive.