Lifecycle of an Enzyme: Mashing and rehydration

Lifecycle of an Enzyme: Mashing and rehydration

Quality over quantity. Sound familiar? Well, the quality of wort extracted is a direct result of the rehydration and mashing procedures. By this point, articles have been read, ingredients have been sourced, and recipes have been written. With a plan for enzymatic balance, rich flavor development, and high extract potential, brewers can look to refine precision operations. The time is now! Let’s explore the process of mashing and rehydration!

Malted barley is an amazing ingredient offering brewers many advantages. Depending on the exact variety, the enzymes necessary for conversion and extraction are supplied in-kernel. Brewers merely need to add water and heat to get fermentable sugars for alcohol production. This process, overall, is referred to as mashing.

According to Mirriam-Webster, mash would be a transitive verb meaning (1) to pulverize into a soft or pulpy state; crush/smash, or, to (2) subject to the action of water with heating and stirring in preparing wort. The irony of this definition is, of course, that brewers must do both in one “action” of brewing. 

Before the mashing procedure can commence effectively, the malted barley must be “milled” between a set of knurled rollers. A majority of breweries accomplish this task on site, with some locales even requiring this step to be legally compliant as a brewery. Small operations will obtain pre-milled malt from a brokerage or co-operative. Either way, kernels are crushed so that the starchy endosperm can reach full hydration and enzymes can begin their work. 

In the process of malting, developments are made to ensure enzyme content is available for starch conversion, and cell walls become porous. During the latter part of processing, moisture is removed and synthesized enzymes are left in a state of “dormancy”. Upon rehydration, these enzymes will continue where they left off, primarily catalyzing starch degrading reactions. Because of this, the start of the brewing process begins with hot water, and, as with every step of brewing, temperature is very important. Get a good thermometer like this one from Hanna Instruments.

A host of enzymes are present in the mashing process. Depending on a brewer's preference, a single-infusion mash, constant ramp, or series of steps can manipulate malted barley into a cacophony of reactions. Each enzyme will respond differently to temperature, so procedure has a large effect. Single infusion temperature rests offer the best chance at consistency, however their impact on final product is limited. With one temperature, enzymatic activity will be a balance across the spectrum with some seeing little to no influence at all on the wort composition. 

Constant temperature ramping is a traditional mashing method employed for a long time. This is certainly effective at creating highly fermentable wort compositions and increasing overall extraction, however there are some potential concerns. Increased activity by certain proteases can break down foam-positive proteins or leave the resultant wort “watery” or thin. Stepping the mash procedure through several temperatures is an ideal way to maximize extraction and tailor wort composition. Short rests at lower temperatures allow proteolytic enzymes to breakdown needed amino nitrogen and peptides for healthy fermentation, without the loss of body. Quickly increasing the temperature moves these enzymes to a less active state, whilst increasing amylase activity for saccharification. Later on, temperature can be increased again, denaturing enzymes and virtually stopping all mash activity.

The purpose of enzymatic action in the mash is to solubilize malted barley compounds. Primarily fermentable sugar, but also limit-dextrins and some proteins. The amount of water present in a mash has an impact on the enzyme activity, and ultimately how many compounds are transferred into the wort. Typically, a range of 1.25-1.50 quarts per pound is a good starting point for single infusion mashes, however complex regimens may require advanced calculations. Thicker mashes will have longer enzymatic activity while thinner mashes will have activity slow down quicker. This can also have an effect on mash rest temperature, if not adjusted for.

Temperature is the most important factor in mashing, by far. High rest ranges, 155-162°F, are known to provide rich body and mouthfeel, while lower ranges, 142-150°F, provide higher attenuating wort. This is because the latter favors β-amylase activity, creating a more complete breakdown of starch to simple disaccharides. The former, high temperature rests, favor α-amylase activity. Even though both are necessary to create a quality wort, the balance between the two will influence the final product heavily. Naturally occurring barley enzymes are extremely sensitive to temperature shifts, so extra care must be taken. A temperature of 152°F is a safe spot for any new brew.

Amylase starch conversion is not the only thing taking place in the mash. Protein degradation, release of micronutrients, and conversion of fatty acids all help make up the complexity of the wort. Free Amino Nitrogen (FAN) is essential to a healthy fermentation, but it must be balanced as well. Proteolytic enzymes that are highly active at low mash temperatures, 113-122°F, are essential for conversion and extraction of malts, however on most commercially available varieties this can lead to foam positive protein degradation. The maltster should handle this work, except in cases of raw grain, or syrup additions. In that case a short protein rest is acceptable.
 

The pH, or logarithmic measure of hydrogen ion concentration in a substance, is important to mashing. When the hydrogen ion concentration changes drastically, it can cause deformation of the physical structure of enzymes. Since enzyme activity and purpose is defined by the 3D structure of the protein matrix, a deformation can render the enzyme completely ineffective. If the enzyme is unable to perform its primary function, then the enzyme is said to be “denatured”. Mashing at a pH range of 5.2-5.4 is ideal for traditional all-barley mashing. At this range, the majority of brewing positive enzymes are active, and not pushed to extremes. The upper end of this range keeps amylases at their optimal action, however lowering to 5.2 can offer more potential extract, improved protein break, and increased zinc, among much more. Finished beer pH will be lower, generally around the 4.5 range. If you need a good meter, pick up a bench top option from Cole Parmer.

Consider the temperature, hydration ratio, and pH when creating a mash schedule. Brewing salts will play a role, but should not overwhelm in most recipes. Set a standardized mixing regimen and rest time, so that future enhancements can be made. Most importantly, measure and take notes! With some practice and patience, it is possible to custom tailor the wort to the exact style of brew. Now, start heating up that water!

 

Meet the Author

J.D. Angell

Meet the Author

J.D. Angell

After several years of providing hazardous materials training and maintenance for the world's largest brewing facility, JD began home brewing countless varieties of craft beer. Some early success and a detour with industrial scientific research engaged his interests in industrial equipment and complex science, while working at a liquid yeast supplier pointed him specifically towards enzymes. Currently heading Bircus Brewing Company in Ludlow, KY, JD blends contemporary flavors with traditional science and innovative techniques. With over a decade of operational brewing and independent contracting experience across 5 time zones, he has amassed a plethora of knowledge to share with fellow brewers. 

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