This week I take a closer look at the mashing process and what is actually going on when we mash malted barley and then sparge it to produce wort during the brewing process.
The Purpose of Mashing
Mashing is, in its most simple form, a process that breaks longer carbohydrate molecule chains into simpler sugars that can be fermented. Yeast most readily consumes simple sugars like maltose and glucose, and mashing creates the simple sugars yeast needs to ferment and produce alcohol in a finished beer.
Malting and Mashing
To understand mashing, we need to take a step back and briefly explain the malting process. Raw barley is simply barley seeds, but brewers rarely work with raw barley. Instead they use malted barley which goes through a process where the seeds are immersed in water, germinate and begin to grow. The process is cut off a few days later when the seeds are kilned or roasted to make malt.
However malting starts the process of converting complex carbohydrates in the grains into a form where they can be broken down to simpler sugars in the mash. Malting also develops the important enzymes that are needed in the mash to break these carbohydrates down further. The two most important of these enzymes are called alpha and beta amylase.
The brewer now takes over where the maltster left off and mashes the malted barley by immersing it in hot water in roughly the 152 F (67 C) range for anywhere from 30-90 minutes. At this temperature the alpha and beta amylase enzymes are active, and work together to break down longer molecule chains into simple sugars that can be fermented.
Alpha and Beta Amylase, pH and Mash Temperature
Alpha and Beta Amylase are the primary enzymes in the mash, and they work in different ways and also perform best at different temperatures and pH levels.
Alpha amylase has higher concentrations in pale malt and 6 row barley malts. It chops long molecules randomly into gluclose chains, some of which may or may not be fermentable. Because it breaks up the chains randomly, it can create both unfermentable dextrins as well as fermentables simple sugars. It has peak activity in the 5.2-5.7 pH range and a temperature of 70 C (158 F). Therefore, mashing at a slightly higher temperature and pH will activate this enzyme, giving you a beer with fewer fermentables but more body.
Beta amylase is the primary fermtable producer. It chops maltose molecules off from the end of longer chains, and can break down the two most popular (amylose and amylopectin) molecules in malt. Since it always produces fermentable maltose when it acts on a molecule, it will give more fermentables than alpha amylase. It reaches its peak activity at a pH of 5.1-5.3 and a temperature of 60-65 C (140-149 F). Therefore mashing at lower temperature and slightly lower pH will give you a beer with more fermentables (alcohol) but lest body in the finished beer.
Sparging and Lautering
After the mash has completed converting complex sugars into simple ones, we next need to separate the sugars as well as color and flavor from the grain. This is done by running hot water through the grain bed in a process called lautering. There are several variations to this including BIAB, recirculation, fly sparging, etc… but the basic goal is to extract as much of the sugars, color and flavor from the grain while separating the husk and grain bits from the wort typically using some kind of filter bed.
I hope you enjoyed this week’s article from the BeerSmith Home Brewing Blog. Please subscribe for regular weekly delivery, and don’t hesitate to retweet, link, like or mention any of my articles on social media.
Related Beer Brewing Articles from BeerSmith:
- Enzymes in Beer: Alpha and Beta Amylase
- Enzymes in the Mash and Mash Temperatures for Beer Brewing
- Mashing for All Grain Beer Brewing
- Mash Temperature and Beer Body in All Grain Brewing
- The German Step Mash Profile for Beer Brewing
- Understanding Malt Enzymes and Color in Beer Brewing
- Mashing with Dr Charlie Bamforth – BeerSmith Podcast #14
- Multi vs Single Step Mashing for Home Brewing
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