The Details of Step-Mashing
TroubleShooting
Mike Boesen — Fort Collins, Colorado asks,
Step mash recipes usually have details about step temperatures and times, like the following example. Use a mash schedule with a 15-minute acid rest at 113 °F (45 °C), a 15-minute protein rest at 126 °F (52 °C), a 20-minute beta-amylase rest at 145 °F (63 °C), a 20-minute conversion rest at 158 °F (70 °C), and a 10 minute mash-out rest at 167 °F (75 °C). In a system with a heated mash tun, do we count the time it takes to get from one temperature to the next? In a Brew-In-A-Bag (BIAB) system, adding hot water can jump the temperature quicker, but would lead to shorter overall mash time. Isn’t that going to affect the result?
Let’s start out with two quick answers to your questions. Heating time is definitely an important part of the mash and it most certainly should be counted. In fact, control over the heating rate is often overlooked as a tool in the brewer’s arsenal of methods to wrangle the enzymatic changes that occur during mashing. This means that quickly heating any mash using hot water aliquots, whether BIAB or an unrestrained mash in a pot, may result in a different wort compared to slower heating using an external heat source (yes, this is difficult in the BIAB system). The question that this all begs to be answered is what mashing profile should be used and how do practical brewers select their mashing method and/or temperature profile when formulating a new brew?
The answer to this question really begins with the Snickers bar story and the concept of malt modification. When pondering mashing, keep in mind that mashing is an extension of malt modification plus the totally separate enterprise of starch conversion. For practical brewing purposes, starch conversion falls under the purview of the brewer, while malt modification can be a shared responsibility between maltster and brewer. Onto the Snickers bar story . . .
Professor Michael Lewis, the venerable and now retired brewing scientist from UC-Davis who mentored so many brewers, likened the cross-section of barley kernels to Snickers bars. The chocolate of a Snickers bar is the husk of barley, nougat is the protein, beta-glucan, and arabinoxylan matrix of the endosperm, and of course the peanuts are akin to starch granules. During malt modification, enzymatic degradation of the nougat exposes the peanuts and makes the endosperm of the malted barley easier to bring into solution during mashing, and also makes wort separation easier during wort collection. As it so happens, proteolytic and cytolytic enzymes, the enzyme types responsible for the digestion of barley’s nougat-equivalent, are more heat labile than amylolytic enzymes — responsible for peanut digestion.
What this means in practical terms is that the job of digesting the nougat is best performed by the maltster. This is why a majority of the lab analyses performed on malted barley relate to modification; soluble protein, the Kolbach index (soluble protein/total protein ration), total beta-glucan, friability, fine-coarse difference, and acrospire length are all indices of malt modification. Brewers using under-modified malts need to pick up where the maltster left off. Not all brewers have a problem with this deal and there are some brewers who prefer using lightly modified malt because of the control they retain over wort composition.
Most base malts these days, even a large percentage from continental Europe, are being malted from barley varieties that produce evenly- and well-modified malts that function admirably when infusion mashed. This is especially true of malts produced with the craft brewer in mind because a large proportion, probably the majority, of craft brewers have infusion brewhouses. Even breweries with the ability to perform multi-temperature step mashes have empirically determined that mashing method does not make much of a difference to finished beer when well-modified malts are used to brew all-malt brews. I do want to clarify for all you step- and decoction-mash devotees that I am not arguing that mashing method is irrelevant. I am just making this point for modern, well-modified malts.
Going back to the question I posed earlier; how does a practical brewer choose mash technique? This decision has been made much easier over the last 20 years or so as malts have become progressively better suited for infusion mashing. Many brewers today simply use the infusion method for every brew, and don’t vary mash thickness, mashing time, or mash temperature from brew-to-brew. Other brewers hang onto step mashing methods even when using modern malts because these brewers have “always” used these mash methods. I confess to being one of these brewers until about 2002 when I started questioning why I was doing things a certain way and began simplifying and shortening mashes. Then there are brewers who really go about matching mash method with their raw material. These brewers brew the most beer by volume, but they fall into the minority of brewers because of the lab methods required to really align mashing, raw materials, and wort/beer properties.
It’s taken a lot of words to provide a little contextual argument to the real message; don’t get too hung up on matching another brewer’s mash profile if you know how to deal with a variety of grist bills in your set up. To paraphrase Charlie Papazian, take a chill pill, sip on a chilled Pils, and don’t sweat the details!
