The last “How to Brew” post dealt with single infusion mashing. The single infusion relies on one temperature of water and grains. Simply stated, you put the water into the grains, stir well (and a couple times during the conversion), and wait. Most grains are good enough for this method to be the primary means of mashing for most types of brews. Of course, there are reasons for “step mashing” your beer.
What is step mashing? Step mashing is a variable temperature method of converting your grain’s sugars. Step mashing requires you to have more than one mash temperature. There is some debate about what it actually accomplishes. Some people do it to help with the head retention or for a more thorough conversion of sugars via the longer wetting and steeping of grains. There are those people who argue that modern malts are of such a quality and modified well enough so as to not require step mashing. But certain styles lend themselves to step mashing. Really, it seems based more on grain type than style of beer…whatever the case may be. Also, it can be used as a viable alternative to decoction mashing (I’ll write on that one later).
Certain styles do truly benefit from this type of mashing. For instance, anything with a fair amount of wheat or rye benefits from step mashing. Grains that benefit from step mashing are those that lack enzymes, have high protein levels, grains and adjuncts with high starch, raw grains, or beers served at very cold temps (I’m borrowing from Stephen Snyder on this point). Temperature marks in step mashing target certain enzymes that operate best at specific temperature levels.
The first temperature of a typical step mash is 122° (all temps in Farenheit). Of course, some recipes call for a stage at 95° as well, but this is more rare. For me, a typical step mash involves mashing in at 132-135°, which will achieve a temp of 122°. This (122°) is the ideal temperature for breaking down proteins that cause chill haze (a collection of proteins that appear as haze once the beer has been chilled) and also increases the amount of head retention by breaking down those same proteins. Anywhere from 10 to 60 min is recommended. Thirty minutes at this stage is typical for me. One more point to remember is that a step mash will also increase amino acids levels, which are important for yeast nutrition. Again, this is often important for grains with few surplus enzymes and for poorly modified malts.
How do I do it? First of all, I explained how I get the 122°, but how do we get it to the range where sugars will be converted? There are two schools of thought. Either you make a thick mash in your mash tun and hold it at 122° for 30 min and then add 200° water one quart at a time until you reach the temp level that you want or you use your brew pot and stove to adjust temps.
I do the latter because I get concerned about temp control and watering down my wort. I do my “rest” in my pot and raise my temp up to the level at which I want to mash and then put it in my mash tun. Some suggest doing a lower end temp rest for mashing and then raising it to higher temps. So, for instance, you do your 122° protein rest and then raise to 148° (the lower end of mashing temps) and hold for 30 min, which gives you a highly fermentable wort. After the 148° rest, you raise it to the upper range (155-158°) which will give you dextrines (non-fermentables) that will increase fullness and mouth-feel. As you might imagine, this could get tricky if you are using water in your mash tun to make these adjustments. For simplicity’s sake, I use the stove and bottom heat to achieve these temps. When I reach my last rest temp, I put the mash in my mash tun and let it complete conversion.
What styles would I do this for? Wheat beers of all types lend themselves to this mashing method. Here is a list of beers for which you should consider step mashing: Altbier, American Lager (the real kind), Biere de Garde, Saison, Bock (although decoction might be better), California Common, Cream Ale, Pilsner, Double Bock, Belgian Double, Dunkel, Kolsch, Lambic, Marzen, Helles, Old Bruin, Pale Ale (based on your preference), Stout (with some wheat content or certain types of grains), Belgian Trip or any Wheat beer. Some of these are more important than others. Stout and Pale Ale, for instance, are highly optional. Some are better with decoction; Altbier and Bocks especially fit into this category.
I know that some of this is unfamiliar, but the process is straightforward enough. Playing around with beer styles is the best way to start step mashing.