What to do with Your Malt: The Mashing Process

Mashing is a critical phase in brewing beer where we convert the starches into sugar. That name might suggest a lot of physicality, but this is all about the science. We need to create the proper environment through temperature-controlled steeping so that the enzymes do the work for us.

There are several methods of mashing including temperature mash, decoction mash, and multi-step mash. We’ll focus on the single temperature infusion method because this is most prevalent with home brewers. There are a couple of core principles for this method. First, temperature control is vital, and we must be aware of it at all times. Second, the process requires 1 quart of water per pound of grain at 150-158 degrees Fahrenheit for mashing, and it requires 0.5 gallons at 170F for sparging.

Note that since we’re using the single temperature infusion method there will be no need to adjust temperature once we establish the process. We’ll heat the water to the necessary temperature, add the grist, and then hold that mixture at that desired level for approximately one hour. Grist is cracked grain, and cracking the grain is crucial to activating the enzymes and promoting conversion. In a more practical sense, cracking is what allows steeping to cultivate the flavors.

When beginning the mash process, bring water temperature to 10 degrees above what the recipe calls for because there will be a drop when you add the grist. Once the mash stabilizes at the desired temperature, begin timing. Most recipes call for 150-158 degrees for one hour, but follow the requirements of the recipe. If you choose to deviate, it’s important that you understand the role temperature plays in beer creation. A lower temperature will result in more fermentable sugars, meaning a dryer beer with higher alcohol content. Higher temperatures will create more non-fermentable sugars, which results in a sweeter, fuller bodied beer with less alcohol content.

Once the mash has steeped for the necessary amount of time, it requires sparging. Sparging is the rinsing of the grain in water in order to leech all additional dextrins and sugars. The key is to allow the water to flow through the grain, out the bottom of the container, and into the brew kettle. It is vital that you do not use more than 0.5 gallons per pound of grain. Over-sparging dilutes the beer and adds an unpleasant grain flavor. Under-sparging results in a stronger beer, but it also results in less liquid than the recipe calls. Although beyond the scope of this article, the experienced home brewer can use it to great effect.

Now it’s time to boil the splurged mash along with the hops. The novice must recognize the need for patience. Keep stirring in order to avoid sediment burn at the bottom of the kettle, and note that this mixture will not reach boil quickly. You can use a lid to quicken the heating process, but you’ll have to pay close attention, and watch for the boil-over. In the final moments of this stage is when you add the finishing hops or other such additions that the recipe calls for.

The mash and hops have now become wort, and it’s important to cool it using a wort chiller. Using a coil and cold water, a wort chiller is able to cool a large amount of wort extremely fast. Fast cooling is important because it promotes the start of fermentation quicker. This is because boiling does not destroy all bacteria, and therefore, you essentially have a race between the yeast and the bacteria, and we want the yeast to win.

Once the wort has reached room temperature (~75F), you’ll want to record original gravity and begin aerating since the yeast requires oxygen for the respiration phase. You can achieve proper aeration through thorough shaking of the fermenter. Now it’s simply a matter of pitching the yeast, covering the fermenter, and attaching the airlock.