I have barely started this, and I have already determined that this will be at least a three part post. Mashing is that big, and that important. It takes into account understandings of botany, chemistry, thermodynamics, physics, fluid motion… a lot of science. Which is actually pretty funny considering that at its core, mashing is putting hot water on crushed grain and waiting.
What’s happening in the mash?
The biggest action we’re most concerned about in the mash is the enzymatic breakdown of starch to sugar. This involves two diastatic enzymes knows as αAmylase —Alpha Amylase, and βAmylase — Beta Amylase. If you took basic biology in high school, you may have done an experiment using a chewed up saltine cracker to demonstrate that enzymes — αAmylase to be precise — in your mouth break down the starch of the cracker into sugars. These enzymes — the same as in your mouth — break down the starchy molecules from the grain into sugar molecules that yeast can ferment.
In general, these enzymes are active at different levels of intensity at roughly the same general temperature range. Balancing them with temperature control is incredibly important to the results of your brew.
αAmylase
Alpha Amylase breaks starches down randomly, and is activated at a higher temperature than Beta Amylase, with its optimal temperature being 153º F. Essentially, this acts as a weed whacker, breaking starches down into complex sugar molecules called maltose. These aren’t as easily fermented by yeast as simple glucose.
βAmylase
Beta Amylase breaks down starches in an orderly fashion. It effectively snips small glucose molecules off the end of the starch molecule’s chain, creating highly ferementable sugars. It acts like a blender, creating a homogeneous mass of glucose. Its optimal temperature is 145º F.
The Balancing Act
We don’t particularly want just one enzyme to be active without the other. A beer brewed with nothing but glucose would be incredibly dry to the point of unpleasantness. Alternatively, a beer brewed with nothing but maltose would be terribly sweet, and not particularly alcoholic. A balance of sorts is the goal of most brewers. We control the balance of glucose to maltose with our mash temperature. A higher mash temperature will result in a more maltose focused conversion, while a lower one results in more glucose.
Very effective conversion takes place at between 152º F and 154º F. Based upon your intended style, you should target your mash temperature to hold somewhere around those two marks, being aware that being higher or lower will result in the potential fermentability of your wort. The mash alone — largely independent of the ingredients — can and will affect the aroma, flavor, and mouthfeel of your beer. A higher temp will result in more body and residual sweetness with a sweeter, maltier aroma, while a lower temp will result in a drier, thinner beer with a less dense foamstand and a grainier aroma. Think about what the intended style is and what you want your final product to be like when planning at what temperature to heat your strike water.
The other side of the coin for amylase enzymes is the heat extreme. You don’t want to overheat your enzymes too early or they will denature and be incapable of converting starches. Do not exceed 176º F during the mash. There is a point when you want to stop enzymatic action that brewers refer to as mashout. We’ll talk more about that at the end of this series.
Next up, what you need to mash, how much it will cost, and how to set it up.
Tags: Amylase, Enzyme activity, Enzymes, Mash temperatures, Mashing