Step mashing beer – the easier way

August 25, 2020
Tips & Tricks

Step mashing – the easier way

Step mashing is an older technique of brewing, mostly used in the past because the raw materials (in this case malt) were less modified and more primitive, therefore harder, and less efficient to use. Step mashing came to rescue in those times, increasing the amount of sugar brewer could extract from the malt and therefore increasing mash efficiency.

Most homebrewers now will not bother following a step mash schedule because malts are so well modified that the general consensus is a step mash will not increase conversion by any great amount. However, there are reasons beyond conversion that you might want to perform a step mash.

Certain temperatures are key in lowering the pH of the mash, breaking down proteins and breaking down beta-glucans. And the most popular reason for step mashing is nothing less than good old german Hefeweizen. There is some evidence that by performing a rest between 43-45°C (109-113°F) you can increase ferulic acid in the wort which is a precursor to clove phenols that you may want in a Wheat beer or Hefeweizen.

Why do step mash?

Well, in most cases you will do simple infusion at  61-71°C (142-162°F), also known as the Saccharification Rest, but in other cases, you want something more specific. These are mostly related to special beers, like before mentioned Hefeweizen with its clove flavors which you want to emphasize or on some beers you want to do Acid rest, to break down those beta-glucans, and avoid a stuck mash.

And it all comes down to enzymes, these little proteins are what makes mashing possible. Enzymes are catalysts, which means they speed up chemical reactions without undergoing any permanent chemical change themselves. And in our case – that chemical reaction is breaking down long-chain starch into short-chain simple sugars, which later on are consumed by yeast to make our beloved brew.

And for enzymes – everything is about temperature. An optimal temperature that is. Each of them works best at its optimal heat level and depending on that level, you control how your beer will look, and taste,  in the end.

Temperature steps

Since we’ve covered the basics of what happens and why let’s go through all of the steps we should be interested in:

35-45°C (95-113°F) Acid Rest – The acid rest is a step designed to lower the pH of the mash and for breaking down beta-glucans which can be useful if using a high proportion of oat or wheat, malted or unmalted. An acid rest works because, at this temperature, phytase enzymes are actively breaking down phytic molecules. There is a slight catch here, this rest takes at least an hour to lower mash pH, so these days it’s most widely used to break down beta-glucans.

43-45°C (109-113°F) Ferulic Acid Rest – A molecule called 4-vinyl-guaiacol is responsible for beer having a clove-like aroma that is desirable in some styles (Hefeweizen, Dunkelweizen and some Belgian styles). Ferulic acid is a precursor to this molecule which is normally bound to other molecules present in the wort. If you perform a rest in this temperature range for 15-20  minutes you can release more ferulic acid into the wort, therefore getting more of the precursor to 4-vinyl-guaiacol.

44-59°C (113-128°F) The Protein Rest – If you have too many long-chain proteins present in your wort you may find you have issues with protein haze and instability if you store your beer for any period. On the other hand - you require some medium-chain proteins in your beer as they help with head retention and body in the finished beer. Although in theory, this rest breaks down protein chains into shorter chains - in modern practice this is something that is best to avoid except in the case where you are using malt that is very high in proteins. With most well-modified malts (and that encompasses around 90% of everything available today), a rest at this temperature is only going to negatively affect the head retention.

At the end - not a rest that is widely used today, as in most cases it only negatively impacts head retention.

61-71°C (142-162°F) The Saccharification Rest – The required rest for brewers, many homebrewers will utilize just one extended rest (60 minutes) within this temperature range. The main purpose of the saccharification rest is to convert starches to simple sugars. Two enzymes are important here, alpha-amylase and beta-amylase. Alpha-amylase’s activity is strongest around 68-72°C (155-162°F) and breaks starch molecules up at random points, therefore creating long chains that result in a sweeter and fuller-bodied beer.

Beta-amylase, on the other hand, is most active from 60-63°C (140-145°F) and breaks starch molecules at the branches, creating much shorter chains. This is an excellent way to produce highly fermentable worts for drier finished beers.

Mostly used temperature for homebrewers is at 65-67°C (149-152°F) as it is a good balancing point between fuller-bodied and dryer finished product. 

How to make it easy

Well, the reason you’re here is the Sous Vide method. And this is the actual way to make it way easier.

In normal conditions, be it a stove or turkey fryer you would need to be next to the mash, checking it, measuring and in extreme situations – adding cold water because you went too far. Not with a Sous Vide immersion cooker. Once your timer goes out at the end of the required step, just go to your mash, set the temperature to the next one, stir the mash a bit and leave it. And so on, until you reach mash out temperature and start preparing your wort to boil.

One more reason to go to Sous Vide. Down the road expect a recipe for a great Hefeweizen (with a twist ;), and don’t forget to subscribe!


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