Ask Mr. Wizard

Why do some grains need to be malted?


Julio Montero Charlotte, North Carolina asks,

Why do some wheats need to be malted and others, like einkorn, not require a malting process?


Grains are malted so that starch contained in the grain endosperm can be released into solution during mashing. The changes that happen during malting are collectively termed modification. And the thing that unites all of these changes is enzymatic production and enzymatic activity. At the end of the malting process, malted grains contain a wide range of enzymes intermingled with partially digested endosperm material. The partially digested endosperm is a mixture of starch, the primary constituent, cell wall fragments (starch is surrounded by cell walls composed of proteins and gums, commonly referred to as dietary fiber, like beta-glucans and arabinoxylans) and fragments of the protein “glue” that binds the endosperm into a hard kernel. The kilning process dries these goodies and preserves the enzymes, resulting in the ultimate brewing package known as malt.

Most beer brewed globally uses a mixture of malted grain, principally malted barley, and adjuncts. The simplest definition of an adjunct ingredient is anything other than malted barley used to contribute extract to wort. Some brewers lump other malted grains with malted barley and reserve the term adjunct for unmalted grains. The major distinction between malted and unmalted grains is the presence of enzymes; any unmalted, starchy ingredient used in brewing must be mixed with enzymes for starch conversion and the traditional source of enzymes is malted barley.

Long introduction for a short answer: Wheat does not need to be malted for use in brewing and there is a long history of using unmalted wheat as an adjunct grain. And einkorn, like other wheat species, can be used in both unmalted and malted forms.

Raw wheat is different from rice and maize/corn — the most common adjuncts — because the gelatinization temperature of wheat starch is low enough to use in all mashing systems (infusion, step and decoction) without having to be specially treated. I am intentionally avoiding specific values for the gelatinization temperature because gelatinization occurs over a temperature range and is affected by mash thickness and varies with grain variety, be it wheat, rice, corn, barley, etc. The take home message is that raw wheat can be easily used in mashing, whereas rice and corn have to be gelatinized, usually by boiling, before they can be added to the mash.

The thing about wheat is that, like barley, it is relatively easy to malt. And unlike barley, wheat sheds its husk easily during harvesting. The term “separate the wheat from the chaff” refers to threshing where the valuable wheat endosperm is separated from the low-value chaff. Since wheat loses its husk, a husk source is required when malted wheat, or a combination of malted and unmalted wheat, is used for brewing. The easiest source of husk material is malted barley, but some brewers add rice hulls to 100% wheat mashes. Malted wheat can be kilned to yield a very pale, enzyme-rich malt that works great for pale wheat beers, or specially kilned to yield darker special malts, such as caramel wheat, chocolate wheat malt, and black wheat malt.
In a nutshell, wheat is a very versatile brewing material with lots of advantages. 2016 marks the 500-year anniversary of the Reinheitsgbot; a law that prevented normal brewers from using wheat as an ingredient because wheat was, and continues to be, a very important foodstuff. This restriction was not applied to state run breweries because the wealthy, ruling class really liked wheat beers and did not want this law cramping their style. So in celebration of this 500-year-old beer purity law, make 2016 the year of the wheat beer and brew with wild abandon!

Response by Ashton Lewis.