Malted barley is important for beer and a good subject for beginning brewers because barley is the plant engine that pulls the beer train. Barley uses the sun to convert water and carbon dioxide into simple sugars. Enzymes help chain sugars into long starch molecules providing energy reserves for the germination of the next crop. In normal conditions, a seed uses this stored energy to break through the soil, start photosynthesis, and send out roots.
The malster derails the process by forcing seeds to germinate in highly controlled conditions.
After the box car arrives, the malt house samples the barley for moisture, bugs, bacteria, and contaminates. After passing, barley is loaded in large silos for brief aging. After aging, a batch or specific weight of barley moves into steeping bins of cool water where it usually soaks for about three days, duplicating spring soil conditions. The barley is drained, spread out, and kept moist as it germinates for six to 10 days at a temperature between 50 degrees and 70 degrees.
A growth shoot or acrospire and short rootlets emerge from the seed. During this process, the maltster regularly checks statistically significant samples for germination and the average length of the acrospire. Germination is quickly halted when the acrospire grows to 50 percent to 80 percent of seed length by gently heating the malt to 90 degrees for 24 hours followed with a final heat near 120 degrees to finish moisture removal. Warm, dry air is forced down through the top of a 1- or 2-foot-deep malt bed as damp air is removed through a perforated screen. After drying, a mechanical process removes the shoot and sprouts.
When the malt is dry, it can go back to the beer train and head out to a brewery, get sidetracked to a bagging facility, or it could be further roasted or kilned to add additional flavor or color. One of the processes is called the maillard or browning reaction and it is responsible for many flavors and hues in various foods and beverages. Small quantities of this specialty grain add amazing depth of flavors when used in appropriate and small amounts.
Base malt and specialty grains need to be milled so they can finish starch conversion and release sugars. Milling crushes the endosperm while preserving an intact husk. Although husks contain tannins we don’t want in beer, proper crushing keeps the husk intact to create a filter bed while keeping the tannins locked up in the husk. Rollers crush malted barley into grist preparing for hydration. Dust released during milling contains bacteria that can contaminate beer so most brewers locate their grist mills in sealed rooms or locations that are not used for fermenting.
The photos accompanying this column show a home brew grist mill built from a selection of recycled metal and wood. The rollers were turned at a lawn mower factory and the metal and wood frame manufactured and assembled at home. The motor previously powered a furnace fan and the hopper, holding up to 30 pounds, was cut from sheet metal and rolled on a table. Both rollers are powered using a reversing chain and idler sprocket.
A copper device feeds the barley into the pinch point and the crushed grist falls through an opening in the frame table into the mashtun. A set of conveyor rollers, previously used to unload boxes from trucks, was shortened, inverted, and covered with plywood providing easy movement of the plastic storage drum and access to the outlet chute. The drum, originally used for malt syrup, has a hermetically sealed removable top preventing the entry of bugs, critters, or moisture and can hold up to 250 pounds.
A homebrewer and beer judge with 25 years of experience, Rick Oftel escaped the Twin Cities and moved to a Bayfield house with a detached workshop. A sealed area holds the brewery used for beer, mead, maple syrup and for coffee roasting.