Beer Studies: Ingredients: Grain (2 of 3)

Malting is the process that takes barley kernels, creates enzymes that break down the kernel's starch reserves, and converts those starches into sugar.

Malting consists of three steps:

Steeping
Germination
Kilning

Steeping

The first step in malting is to step barley in hot water until the kernels have absorbed almost half of their initial weight in water. This hydration activates the enzymes that convert the seed's starches into sugars.

Germination

The wet barley is drained, held at controlled temperature and humidity, and aerated until the seeds begin to germinate. A shoot, called an acrospire, begins to grow beneath the husk.

Germination activates the production of enzymes that convert the starch reserves, called the endosperm, into sugars for the newborn plant.

The length of the acrospire is an indication of the extent to which the starch has been converted, and when the length of the shoot is almost the same length as the kernel, all of the starch has been converted into sugar.

The process of converting the starches into sugars is called modification. When all of the kernel's starch has been converted into sugar, the malt is said to be fully modified.

At this point in the process, the barley is called green malt.

The acrospire will continue to grow and consume the kernel's sugar, so growth is stopped by drying the barley in a kiln, which is a type of oven.

Kilning

Kilning is the source of nearly all malt flavor.

Inside the kiln, the malt's protein and sugar are heated to produce the malt's flavor, color, and aroma.

Think about a piece of bread in a toaster. How long the bread is in the toaster affects the color and flavor of that piece of toast.

By varying the temperature of the kiln, the moisture of the grain, and amount of time the grain is in the kiln, different flavors and colors of malt are produced.

There are three main types of malts:

Kilned
Stewed
Roasted

Kilned malts (Pils, Pale Ale, Vienna, Munich, Victory) are dried and kilned at relatively low temperatures (90-180 F) and have a mild flavor with hints of grain and toast. Munich malts are kilned at higher temperatures (200-350 F), and develop more biscuit, bread, and bread crust flavors.

Malt used to be dried over an open fire, which imparted smoky flavors to the malt. The introduction of coke as a fuel source sparked the development of pale malts. Coke, a derivative of coal, burns at a lower, more controllable temperature than wood, and without soot and smoke.

One of the advantages of pale malt is that it contains more fermentable sugars than more darkly roasted malts, as roasting at higher temperatures makes some sugar unfermentable.

The term pale ale was first used in the early 1700s and was in general use by the 1780s. During this period, pale meant lighter than dark brown.

Stewed malts (Crystal, Caramel) are made from still-wet green malt, which is kilned with moist heat until the sugar liquifies inside of the barleycorn. Further heating caramelizes the sugars, which makes them unfermentable. These unfermentable sugars add honey, toffee, and caramel flavors.

Roasted malts (Chocolate, Black) are dried before being roasted at high temperatures (350 - 450 F). Roasting at high temperatures eliminates enzymes and fermentable sugars but adds a deep color. These malts are used both to add color, and to add their bitter chocolate, coffee, or burnt toast flavors.

These very dark malts were first made in an iron cylinder similar to a coffee roaster. This rotating cylinder allowed the malt to be roasted without burning. The device was patented in 1817 and sometimes this type of malt is referred to as Black Patent Malt. The development of Black Patent Malt allowed brewers to use Pale Malt, with its higher fermentable sugar content, as the base of their beer, with a small amount of Black Patent Malt added for coloring and flavor.