Barley is the primary grain used in beer, and bread is made of wheat. But the thing is, you can make bread with barley, and beer with wheat. So what gives?! Hint: there are good reasons for both.
There are two main brewing characteristics that make the differentiation, and both are important to the same process, lautering.
Lautering is a key process between mashing and boiling — essentially, after steeping grain in hot water, the brewer then has to separate the liquid, now rich with the sugars and proteins needed to make beer, from the grain. Simple concept, but tricky process.
This is accomplished by creating a porous grain bed that serves as a “filter.” (This happens in nearly all beers, so don’t confuse it with actually ‘filtered’ beer, which is a process that, if it occurs, happens much later.) The liquid is circulated through the grain bed until it’s clear, then run through the grain into the kettle.
Sounds simple enough. But the grain bed has to be the right consistency, with the grain ground up to the proper “crush,” or the liquid won’t be able to flow through. When the bed collapses and the liquid can’t get through, that’s called a “stuck mash.” Not fun. It can add hours to the brew day and ruin efficiency.
This is where barley’s unique characteristics come in. Barley grows with a husk that keeps the grain bed from lumping together, and provides the fine areas for liquid to pass through. Wheat, which is huskless, provides no such grain bed support.
“Think of the husks as life jackets” said Barrel-Master Keir Hamilton, “otherwise, the grain would compress on the bottom and inevitably stop the liquid from passing through.”
The second characteristic is protein content: barley’s is lower than wheat’s. The protein content of wheat makes the mash smooth and slick, almost like clay. This “gummyness” ups your chances of that dreaded stuck mash.
Not to say wheat can’t be used in beer — certain styles depend on it. Such as… you guessed it… wheat beers. Hefeweizens and Belgian wits, for instance, utilize that high protein content in wheat to make softer, “rounder” feeling beers. We also use a small portion of wheat in some brews, like Sweet Action. That extra protein helps with head retention and adds some weight to the mouthfeel of the beer.
Generally speaking though, barley’s husk and lower protein content make it ideal for brewing beer and wheat’s higher protein helps to create the strands of gluten that capture air and give bread that soft, delicious fluffy, texture. (The trapped air actually means that bread is technically a foam.)
The main takeaway? If we switched it up, bread would be flat and making beer would be a mess. That’s the Barley vs. Wheat discussion in a nutshell (or grain husk).