Enzymes in Beer: What’s Happening In the Mash

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As #homebrewers, we’re usually never satisfied until we know how things work. We constantly ask why and how something is done until we understand the basic concept. When you start brewing #all-grain, you hit a certain temperature to hit a specific characteristic because you were told to do so. You start picking up on words like alpha-amylase, beta-amylase, mash out and protein rest, and now you’re more curious than ever about what’s going on in the mash.

Here we’ll discuss the #enzymes in beer, which convert the starch in malt into soluble sugars. By understanding and making enzymes work for you, an all-grain brewer can control a multitude of components in their beer. Here is a list of the attributes of a beer that can be controlled during the mashing process:

• Aroma
• Flavor
• Body
• Overall mouthfeel
• Attenuation
• Color
• Alcohol content

What Are Enzymes In Beer?

Enzymes are proteins that are found practically everywhere—your saliva and digestive system, plant photosynthesis, and most importantly, your livers. They have an important role as a non-living biomolecule because they catalyze biochemical reactions. Each enzyme is made up of several thousand different amino acid chains which take on specific shapes suited for specific jobs. In other words, they make reactions occur quickly and at the temperatures of living organisms. They join molecules together, take large molecules apart and rearrange molecules into something different.

Each biochemical reactions is catalyzed by a very specific enzyme. The molecule the enzyme acts on is called a substrate, and the enzyme is usually named after the substrate (i.e. Beta-Glucanase acts on Beta-Glucans). Just know that the enzyme’s shape is fragile and can be damaged by a multitude of factors, thereby rendering the enzyme unable to act as a catalyst. This is called denaturing the enzyme, and once it’s been damaged, it’s very difficult to renature it.

The rate at which the chemical reaction occurs is affected by temperature, enzyme and substrate concentration and pH. Enzymes catalyze reactions more quickly as temperature increases in their specific range. But, they’re also denatured by heating above their specified range, and reach peak activity just before they are destroyed.

Mashing Enzymes In Beer

All the enzymes you’ll need for conversion are present in the final malt. The malting process develops enzymes that reduce starches and proteins during malting and mashing, which helps create better clarity, head retention and body.

For homebrewers, we are concerned with the activity of two primary enzymes in beer: alpha- and beta-amylase.

Alpha-amylase breaks down large, complex, insoluble starch molecules into smaller, soluble molecules for the beta-amylase. It is stable in hot, watery mashes and will convert starch to soluble sugars in a temperature range from 145°F to 158°F.

Remember that the temperature range is important because as you reach higher temperatures, the denaturation process increases and enzymes are mostly gone within five minutes. Pouring grains into hotter “strike” water to account for temperature drops can cause problems, too. Exposure to hotter temperatures even for a few seconds can affect enzymatic activity, so make sure to get your temperature down as quickly as possible.

Beta-amylase is the other mash enzyme capable of breaking down starches and creating soluble sugars. After the alpha-amylase enzymes create smaller soluble molecules, the beta-amylase enzymes create most of the fermentable sugars by breaking down starch to create maltose, glucose and maltose. These enzymes help create lighter bodies and more alcohol and are most active from 131°F-149°F. As the temperature approaches 149°F, these enzymes are operating extremely fast, but are also being denatured quickly. In short, if the mash is held at a temperature within the beta-amylase range, then a greater proportion of soluble sugars will be maltose and thereby be more fermentable.

Temperature Rests in the Mash

Mash temperatures play a very critical role in determining the body, fermentability and developing the aroma and flavor profile of your beer. Depending on the style of beer brewed and the type of malt and/or adjuncts used, a different mash temperature or a combination of temperatures and schedule may be best for the brewing beer.

Influencing Factors on Denaturing Enzymes in Beer

Alpha and beta-amylase act together to degrade starches to produce a range of soluble sugars in the wort. Below a certain temperature (149°F), alpha-amylase activity is low and so the large starch molecules remain insoluble because the enzyme is unable to break them up. Same goes for above a certain temperature (150° F), beta-amylase activity is hindered, limiting the amount of fermentable sugars for the wort.

These temperature ranges are small, and leaves little room for a brewer to operate and influence the types of sugars that end up in the wort. A lower temperature results in a wort that is more fermentable but may yield slightly less, while a higher temperature will yield less fermentability but increased extract efficiency. Here are some important influencing factors on denaturing enzymes in beer.

• Enzyme and substrate concentration
• Temperature
• pH

Enzyme & Substrate Concentration

Enzyme and substrate concentration is how concentrated your mash is, and mostly dependent on mash thickness. Although not a critical factor, mash thickness is still important to consider when you start mashing. A thick mash is anywhere between 1-1.25 quarts water/pound of grain.

A thick mash gives a quicker starch conversion and is more beneficial for protein breakdown because it offers better protection for your enzymes (i.e. beta-amylase). It’s more suited for step mashes because enzymes are not denatured as fast by temperature increases. A thin mash is anywhere around 2 quarts water/pound of grain, which dilutes the concentration of enzymes and thereby gives them less protection, a slower conversion, but provides a more fermentable mash because the enzymes are not inhibited by a higher concentration of sugars.

Temperature

Each enzyme has an optimum temperature, the temperature at which the enzyme is most active. Once the temperature goes below or above the temperature range, you affect the productivity of that enzyme. Think about a cold morning. You’re lethargic and slow, but as it warms up you start to move faster and your energy improves. However, if it gets too hot, you start to slow down again. This is essentially how enzymes work. More specifically, the active site on the enzyme changes and the substrate that pairs with the enzyme will no longer fit and becomes inactive.

pH

Mash pH is another factor that affects the activity of various enzymes. It should fall within a range of about 5.2 to 5.5 for the primary enzyme activity. If you mash using distilled water, you’ll end up with a pH in between 5.8 and 6.0. Adding calcium ions to the water will cause the mash pH to drop down into the 5.5 to 5.6 range, with additional calcium ions dropping it further. You’ll want to use a pH strip to calibrate your water pH level as you mash.

Key Take Aways

• Although enzymes are fragile, they are reusable and generally affected by temperature and pH.
• Enzymes have an optimum temperature and pH that they are most active.
• Enzymes have a significant affect on finished beer and are also present in yeast cells.
• Understand the primary mash enzymes (alpha and beta-amylase) and their optimal temperature and pH levels to achieve best results.
• It’s important to understand the factors that denature enzymes.
• Know what you want to accomplish before deciding your mash technique.

Sources: “Making Enzymes Work For You” by Randy Scorby, BJCP Continuing Education Director and Grand Master II Judge, 2015 National Homebrewers Conference Seminar

http://www.homebrewersassociation.org/how-to-brew/enzymes-in-beer-whats-happening-in-the-mash/

Homebrewing: Introduction to Mashing and All-Grain Brewing

Making the jump from extract brewing to all-grain brewing can be daunting. There is all new terminology to learn, a seemingly an endless supply of expensive equipment, and more science than most of us have done since high school. But the truth is, starting out in all-grain brewing doesn't really have to be hard or expensive.

The Brew-Boss® home brew system is an all electric home brewing system that allows home brewers to brew extract and all-grain recipes with complete and accurate automatic control of temperature and timing. 

Before we jump into recipes, we need to look at the biggest difference between brewing an extract beer and an all-grain beer. All the sugar in liquid or dry malt extract has been extracted from base malts. After the malt has been processed, it's condensed into a form that's easy to package and work with. When making an all-grain style recipe, the sugar extraction step is done by the homebrewer through a process called mashing. Mashing gives the homebrewer complete control over the type of sugar that is extracted and gives more flexibility with the varieties of grain that can be used.

Mashing simply means to combine crushed grain with hot water at a ratio of around 1.25 quarts per pound of grain. The grain will soak for about an hour, and then the liquid will be drained from the grain. Once the liquid is separated from the grain, you can proceed with your brew day in the same way you would an extract batch. While it sounds trivial, beneath the surface of that simple grain and water mixture is a myriad of complex chemical processes that produce fermentable wort.

Enzymes

Enzymes are proteins that speed up chemical processes. Mashing activates enzymes that naturally exist in the base malts. A wide variety of enzymes are present in base malt, and each one facilitates a different chemical process. The most useful enzymes for homebrewers are the ones that break down complex carbohydrates into simple sugars for the yeast to eat. Other enzymes in the mash will help eliminate proteins that cause haze, and some will produce nitrogen compounds that aid in yeast health during fermentation.

There are some enzymes that the brewer wants to avoid, such as ones that will destroy head retention or create watery mouthfeel. The challenge of the homebrewer is to coax out the enzymes that will improve the beer, and avoid the ones that will cause problems.

Mash Temperature and pH

Different enzymes will activate and deactivate depending on the temperature and pH of the mash.

Different enzymes will activate and deactivate depending on the temperature and pH of the mash. For the homebrewer just getting into all-grain style recipes, controlling the mash pH is not as big of a concern as controlling temperature. Mixing the right proportions of grain and hot water on a homebrewing scale naturally produces a pH that is between 5.1 and 5.5, which is ideal for the enzymes we want to activate. Testing the pH is as simple as picking up inexpensive testing strips from your homebrew shop. Remove a small ladle of liquid from the mash after it has been thoroughly mixed and immerse the testing strip for the length of time listed on the package.

Temperature control is key to proper mashing. In order to activate the enzymes that convert grain into simple sugar, the mash temperature must be between 145°F and 158°F. For most styles of beer, a mash temperature of 150-154°F is used, and will produce a wort that can be easily fermented by the yeast while retaining a medium body. If the mash temperature is in the 145-150°F range, the enzymes will produce highly fermentable sugars and the final product will have a drier finish. Mash temperatures in the 155-158°F range will produce sugars that are harder for the yeast to ferment, resulting in a fuller bodied beer. Mashing in the lower temperature range is appropriate for styles like a Saison or a Tripel, where the higher temperature range is used for Scotch ales and Sweet Stouts.

When first venturing into the world of mashing and all-grain brewing, proper mash temperature can be very difficult to achieve.  Using the the Brew-Boss system dials in the correct temperature.  If you don't yet have a Brew-Boss my rule of thumb for people just starting out is "Close is good enough". If the thermometer in your mash is reading within 5°F of your target, you have nothing to worry about. The thermometer was not even used in commercial brewing until at least the late 1700's, and widespread use didn't happen until much later. Prior to that, it was impossible for brewers to know exactly what temperature their mash was at, and presumably they were made able to make decent beer. You should always try to hit the proper mash temperature, but don't stress out if you miss it, get a Brew-Boss.

Mashout and Lauter

After the mash sits for about an hour, the next step is to stop all enzymes from working. Homebrewers usually accomplish this by adding hotter water to increase the mash temperature to 170°F. At this temperature, all enzymatic activity is stopped, and the sugar that was produced begins to flow freely like honey in the microwave. This step is called the mashout. The temperature shouldn't exceed 170°F, otherwise unpleasant tannins from the grain will leach into the wort.


Lautering is a brewing term for draining the liquid wort out of the grain. There is a lot of different homebrewing equipment that will help you with lautering, ranging from pre-made heavy strainers to a do-it-yourself braided hose for the more crafty homebrewers. The first recipes we'll be looking at will use the simplest and cheapest method of lautering, called the brew-in-a-bag method. After the the wort is separated from the grain, the brew day proceeds in the same way as when you brew with an extract-style recipe.


http://drinks.seriouseats.com/2011/05/homebrewing-introduction-to-mashing-how-to-all-grain-brew.html