How are enzymes used in brewing?

How are enzymes used in brewing?

Much like yeast, enzymes have been used in brewing long before their known existence. In fact, the word enzyme has its roots in yeast itself. The term, enzyme, was known to be first used by the scientist Wilhelm Kuhne in 1878, and comes from a rough Greek translation of “within-leavened”. 

Yeast cells reproduce exponentially with help from enzymes as exampled in this open fermentation. One mole of glucose will be metabolized into two moles of ethanol and two moles of carbon dioxide during the fermentation process. 

Realistically, enzymes have a place in brewing that far exceeds all other contributions. From start to finish, they impact every aspect of color, flavor, and aroma. To understand the role enzymes play in brewing is to better understand brewing itself. Here we will attempt to de-mystify enzymes and their purpose in brewing. Explore with us as we discuss where enzymes come from, what they are, and how they help us brew!

Where do enzymes come from?

Where do enzymes come from?

As a term, enzymes originated from Wilhelm Kuhne around 1878, however they may be one of the oldest known protein complexes. Years earlier, in 1833, Anselme Payen discovered “diastase”, the complex of enzymes responsible for starch to sugar conversion. This would kick-start the trend of –ase and -ose naming, but more importantly the research applications of enzymes overall. 

More than 20 common amino acids make thousands of proteins necessary for enzyme formation. The combination of amino acids and the linkages between them define the shape of the enzyme. 

Literally meaning “within-leavened”, enzymes are present inside our main ingredients of beer. In barley, enzymes are synthesized inside the aleurone layer of the barley kernel during the germination process. They are necessary for a seed to grow into a living organism, primarily for releasing stored energy. In order to exploit these natural characteristics, maltsters have spent centuries refining best practices to enhance enzyme production and balance useability with flavor and color. We brewers take this dance a step further in recipe construction and brewing techniques.

As any good brewer knows, starch conversion is only half of the brewing equation; the other half is fermentation. Yeast also makes use of naturally occurring enzymes to process complex sugar chains into simple ones. Invertase, specifically, will split a sucrose (disaccharide) molecule into a glucose and fructose (two monomers). Maltase present inside the yeast cell will split two glucose monomers from Maltose (disaccharide). The latter example shows the common protein-carbohydrate naming convention of -ase and –ose. Together, these enzymes are part of a complex called Zymase, first discovered in 1897 by Eduard Buchner. He was able to prove fermentation could take place outside of a living organism, a very controversial concept at the time. Historically, it is likely that enzymes formed early on, after the formation of simple amino acids. They may in fact be the key to life!

Heating enzymes can often de-nauture them, rendering them inactive. In the case of pineapple, bromelain can prove challenging on meat, or in beer. Grilling for a few minutes can caramelize sugar, more importantly, undesirable enzyme action can be limited.

What are enzymes?

What are enzymes?

Enzymes are generally proteins formed by about 100 to 1,000 individual amino acids that have linked together. The bonding sites of these amino chains physically forms the protein into a uniquely complex shape; Think 3-D snowflake. Due to the unique shape of the enzyme protein, it is able to catalyze very specific reactions. Each shape is so unique, it is often referred to as a “lock and key” allowing only exacting shapes to bind in the “active site”. From our example above, Maltase will only “fit” two molecules of glucose, and they must be linked by a a-1,4 glycosidic bond. Another bond between two glucose molecules, or a glucose and fructose molecule, would not be affected by the enzyme Maltase.

Here we see the complex structure of maltose. Intertwined amino acids bonded with specific linkages dictate its shape. Relative to its size, the active site, where catalytic reaction occurs, is quite small. 

Enzymes catalyze reactions at an exponential rate. Acting as a facilitator, they can increase the rate of naturally occurring reactions by rates as high as a million times. This is what makes most practical chemistry possible. Without enzymes brewing would simply not occur. In fact, most of life (if not all) would probably not occur. Reactions would take too long, or molecules may not be able to combine into essential compounds.

Much like technology, enzymes are a broadly applicable category that can reduce the activation energy required for progress to take place. As any good scientist knows, less input energy for the same or greater output is a huge win. Enzymes offer an opportunity to not only improve efficiency and reduce labor, but to also direct results in a targeted way. 

Why are enzymes important to brewing?

Why are enzymes important to brewing?

Brewers focus on enzymes for two main results. First is starch conversion. “Diastase” enzymes enable long chains of glucose molecules to be “cleaved” into smaller, simpler, glucose linkages. These “conversion” enzymes are loosely defined as a group, with many enzymes in the category specifically targeting degradation of cell walls, hydrolysis of glucose chains, and much more. Barley is a main ingredient of choice due to its balance of enzymes and gelatinization temperatures. It offers a simplified processing compared to other starch sources.

Seedlings use enzymes to convert stored starch into useable energy. With this stored energy the plant is able to build enough structure to begin collecting light for more energy.

Second, and arguably the most important part of brewing, is ethanol production. As brewers, we often say “brewers make wort, but yeast makes beer”. Yeast is essential for brewing primarily because of its ability to metabolize sugar into ethanol. This is done by enzymes within the yeast cell walls. Enzymes such as maltase and invertase allow for processing saccharides into glucose, and eventually into ethanol and carbon dioxide. The desired wort composition varies by style and yeast selection, with glucose monomers influencing ethanol and ester production and polysaccharides providing mouthfeel and body. Without a proper wort composition, yeast will fail to metabolize ethanol.

Often overlooked, there are many other enzymes able to aid in processing. From b-glucans in lautering improvements to alpha acetolactate decarboxylase in maturation and stability, enzymes can enhance (or degrade) your efforts. Due diligence is required. Discuss your thoughts with colleagues and friends, and research independently to learn more about targeting enzyme efficacy.

On a final note, some brewers may be hesitant to explore use of supplemental enzyme additions to their processing. The reality is they are already influencing enzyme reactions during the course of their brews. Hydration ratios, temperature and rest times, and even yeast strain selection, all influence the behavior of enzymes during brewing. Manipulating your techniques and ingredients is often looked upon favorably, so let us push a step further and direct our enzymatic attention!

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Let the good times roll!

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Lab demo: better wort separation with enzymes

Unmalted rye can lengthen mash separation times. This demonstration proves that our enzymes significantly cut filtration times in high-percentage rye brews.