The Malting Process
Make sure you begin with raw, whole, untreated grain. If you purchase the grain from a feed supplier or farm store, make sure to ask for feed grain, and not seed grain. Seed grain is often treated with fungicides and other chemicals, and cost far more than whole feed grain. I usually malt no more than 10 pounds of grain at a time. I use a large food-grade plastic tub to sprout the grain. Make sure to wash the grain thoroughly by filling your container with water above the level of the grain, agitating the mixture by hand, and pouring off the water several times. Remove any floating debris and broken kernels. Finally, fill the container to the top of the grain level with cool water, changing the water every 6-8 hours. Allow to soak for a day or so. When grains have rehydrated, drain the water, cover loosely, and allow to sprout in a dark, room temperature location. Rinse and drain off all excess water every 6-8 hours, tossing the grain gently each time. Oxygen is important to the growth process, but a loose cover can help keep molds from forming on the surface. Another technique is to thinly spread the moist, rehydrated grains onto mats or screens. I have found the container method sufficient for all grains except corn. A note about corn: the corn I was able to obtain has a great deal of broken kernels. Removal of as much broken material before rehydration helped greatly with germination. The next time I germinate corn, I will try the mat method.
A rule of thumb for the proper level of germination is when the acrospire (the sprout) has grown to the length of the seed. This rule, however, does not make much sense when working with a seed as small as sorghum. I allow sorghum to reach 3-4 times the seed length. The longer you allow the grain to germinate, the more enzymes you will end up with in the final product, but at the expense of lowering the amount of useable starch to convert into sugars.
Once the grain has reached the desired level of germination, remove the grain from the malting container onto a dry towel, sheet or screen. Allow the grain to air dry for a day or so. The next step is to kiln, or dry, the grain completely in an oven. Kilning also destroys some of the desirable enzymes, so allowing a portion of the grain to completely air dry at low temperatures creates what is known as green malt. The use of a small percentage of green malt in the mashing process should help with the low levels of enzymes. Higher temperatures, however, are necessary for developing the flavors and aromas needed for beer brewing. As the temperature and time increase in the kilning process, color and taste intensify. Temperatures under 150F create a light, mild malt; between 150-300F, brown malts; and 300-450F+ dark, highly roasted coffee and chocolate malts are made. Experiment with different time/temperature combinations on the same batch of grain to develop a feel for the kilning process. Note: when moist grain is kilned at around 150F, caramel flavors and aromas are made. Experiment with the amount of residual moisture in the grain when you begin the kilning process.
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