This article focusses on small-scale production of barley base malt, which is where most maltsters hone their skills before moving on to specialty malts and malting other grains. With minor tweaks, we can malt any grain legume or seeds following this technique. Also by just altering the roasting (kilning) one can convert base malt to specialty malts.
When attempting at barley malt, be prepared for a week long tending and caring of grains to make the perfect malt. Soaked grains need to be hydrated and checked for mold every 4-6 hours. Apart from that, it is a natural process without any intensive labor involvement. Grain is first steeped in water under specific temperatures to get them sprout. The process is stopped when the grains reaches maximum starch capacity. Then the sugars and starches are extracted. This extraction process is important as the sugars give the food that yeast needs to convert the wort to alcohol.
Malt serves various purposes in brewing. It affects right from the color to the sweetness of the beer or any beverage. Malt also affects the alcohol content of your brew. It is like the backbone of your brewing and gives the necessary starches and sugars required.
Diastatic or Non-Diastatic Malt:
Also, one confusion that arises while talking about malted barley is, it being diastatic or non diastatic. When we mention normal malted barley flour it generally means diastatic malt powder. Diastatic refers to the name of the enzymes that is created in some grains when they are sprouted. These enzymes feed the yeast by converting starch to sugar. While non diastatic malt grains are processed involving higher amount of heat. This kills the enzymes and so is no longer diastatic. The diastatic malt powder is used to speed things up whereas the non diastatic provides a more concentrated flavor. The former adds to the color and flavor and at the same time effects the developing chemistry of the brew or dough. While the later just provides flavor and color.
Now that we have a basic idea of barley grain malt let’s quickly head towards the process of producing the barley base malt.
Barley Grain Malting: Home Recipe
- a bed or surface to spread out the malt
- some buckets to wash
- 5 kg Barley with husk it will yield only 4kg
- 15 liters water
- Preparation of grain: Weigh out the barley in a large bucket. Clean the barley and try to remove all foreign material. Sometimes other grains (especially mustard) are also present which needs to be sorted out. Winnowing over a table fan is quite effective. Do not do it indoors because of the dust it generates.
- Final malt weight will be 80% of the starting barley weight. If we want 4 kg of malt, starting with 5 kg of raw barley is ideal. Barley has a moisture content of 12% while the malt is just 4% water, creating a ~8% weight loss. About 6-7% of the loss is due to CO2 respiration during germination. Another 3% cleaning loss occurs as the shoots/ rootlets that the seeds develop are cut off later.
- Washing: Although organic grains are preferred, most commercial grains have pesticides sprayed or fumigated on them during cultivation and storage. Some chaff, hay and lots of dirt often finds its way into the pack. Any under-developed grains, hollow grains due to insect bites and other organic waste that will not germinate, will rot.
- Luckily, a basic submerging of grains (about 10cm of water above the grain level) is sufficient to clean the grains and get rid of all the above cases. Using cold water (near body temperature) is preferred so that hand rinsing is comfortable. Industrially, they use pressurized air to create the agitation in the tank.
- Skim off the floating debris. I sometimes have to change the water twice or thrice, until it is clear enough. It is advisable to use a sieve or mesh so that we do not loose grains in the cleaning process.
- Steep: The goal here is to hydrate the grain until it reaches about 45% moisture. Soaking causes an increase in weight and volume. The first aspect is to promote germination and waking the grains up. Therefore, we alter the soaking with air rest (draining the water out so that grains can breathe). Different maltsters follow different techniques but I would recommend an hour exposure to oxygen every 2-4 hours for the next one day ideally.
- The second aspect to remember is that germination (chitting in this case) is an exothermic reaction. That is the reason, it is recommended to use a thermometer to monitor the temperatures and keep it close to 15OC. An old refrigerator with a thermostat can also make life easy. High temperatures promote mold and microbial activities, which can cause grains to rot (acidic).
- Third aspect: The key to a good malt is uniform conditions. The grains need to be subjected to even level of hydration, the same level of temperature and exposure to oxygen. Unevenness will cause variation inside a batch and lead to uncontrollable results. Spraying cold water on the grains on the top during air-rest prevents them from drying too much.
- Some books recommend longer steeping times but since Indian conditions are warmer, I cut them down by half. In addition to moisture, I closely monitor the chitting, and moisture (42-48%) levels during this entire process.
- Germination: The grain changes physically during germination. Rootlets push out of the husk and lengthen. Later, the grain’s first shoot (called the acrospires), grows inside the husk. These kernels will be easier to roll between the fingers. All these are the classic signs of modification during germination. Steeping initiates the enzymatic processes necessary to make starch available in the grain’s energy reserves, (called the endosperm,) and it is now prime time for the enzymes.
- The maltster’s job during germination is to mix/ turn the grain and track modification. Turning detangles rootlets prone to grow into clumps and disperses heat and CO2 produced by the grain’s respiration. Also, the matted/ clumped grains are difficult to kiln and hence discarded. A simple combing cycle every 4-6 hours (one in the morning, another in the noon and third around dinner) is all it takes. Modification is tracked in order to know when it is time to kiln.
- Move the grain from the steeping bucket to a germination chamber. I use a woven foldable cot with a bedsheet on it. However, most people just spread some tarpaulin (plastic sheet) over the floor to create a uniformly spread grain bed of depth 3-15cm.
- For cooling, air conditioning is best but swamp desert coolers with mystifiers (which spray water) is ideal. Unless the room is humidified artificially, chances are the grains will dry out. Irrigation timers can be reconfigured to spray water every 30 minutes and help maintain temperature and humidity. Be careful to have proper drainage (cots come in handy), otherwise the waterlogging can cause grains to rot and invite molds.
- Keep in mind to measure the grain bed temperature and not room temperature. The simple rule is that by doubling the thickness of the grain bed, we reduce the surface area by half. This would mean that one has to turn the grain twice to prevent matting and to maintain the same temperatures.
- When we check on the grain, please use the senses to make sure things are going smoothly. Be watchful of any pest, mold, discoloration or abnormalities. If germination is going well, smell cucumbers or fresh-cut grass will fill the room. If it is not going well, the smell may be more moldy or rotten. Mold or rotting can happen when the temperature is too high and the grain is too moist, or if we have too many broken kernels in the batch. The rootlets will be bright white and stiff at first but are likely to turn yellow as growth progresses. Finally, they become soft if the grains are drying out.
- Plotting the shoot length, temperature and moisture helps keep track of the progress. Professionals also track the growth of the acrospires. They will take about 20-50 grains sample, split the outer layer with fingernails and track its development.
- Kilning: Once the germination reaches the desired state, it is time to dry the grains out. Turning off the water, blowing in dry air (even ceiling fan helps) and ventilation helps dry the grains out. If we are malting over a cot, it can be easily moved under the hot sun to dry the grains.
- After about 6-8 hours in a dehydrating oven or under the Sun, the moisture will drop to less than 25%. We then move the grains to a kiln. The goal here is not to roast the grains but to dry them out. Exposure to too high temperatures can denature the enzymes. While if the kiln has not brought down the moisture to 3-5%, the grains will spoil. The aim of kilning is to hibernate the enzymes so that their action can be resumed easily on the brew day.
- For a small batch, one can use baking trays. For a larger batch, a DIY wooden cabinet with trays, electric coils for heating and a big blower for dehydrating are what will be needed. Airflow helps in ensuring that the drying is fast.
- Steps 1-3 for most specialty malts are the same. The kilning makes the difference. By tweaking the temperature, time duration and moisture: over 50 different types of malts can be prepared from the same grain and setup (except peat and black malts that needs coffee roasters)
- For base malt: We will do free drying (lot of dry air or Sunlight) for 5-8 hours until moisture is reduced to about 25% and all surface moisture is dried. The husk feels dry but the core is moist. If we are using a dehydrator, then keep the grain bed temperature about 50-55OC for the first 8 hours to achieve 25% or lower moisture.
- Move the grains to the kiln or dehydrating trays, we raise the temperature to 60-65 OC for 4 hours.
- Once the grains reach about 10% of moisture, it is time to cure. We use high temperatures (80-90 OC for about 3 hours) for most base malts. This adds maltiness, brings down the moisture to 3-5% (which is needed by most brewers) and adds color to the grain.
- Kilning schedules vary immensely based on the malt that we are making. Ambient temperature, moisture, variety of grains, batch size and even equipment have an impact on the schedule. Hence, micro-malting is often more an art rather than a science. Chewing on the grains and inspecting the color of their core is often the only guide used by seasoned professionals. Turn the grains to ensure uniform heating and moisture across the bed.
- Kilning is an intensive job, which requires human intervention every 15-30 minutes, even with the most automated machine, and requires huge amounts of electricity/ heat. Although most brewing books recommend
- Debearding: When the grain is done, take them out and let them cool to body temperature (preferably in the tray). The brownish rootlets need to be removed. They not only introduce tannins but also bitter flavors, which are not appreciated. (Remember wheatgrass shake’s taste).
- If the grains are dry, a bit of churning is all it takes to shake off these rootlets. Put the malt in a bucket and rub them between the fingers. The clumps become brittle during kilning and should come right off.
- After this, winnow them using a table fan and a tray. The malt falls straight below and the rootlets form a heap at a distance. Please remember to wear masks, not have kids & pets around while handling grains and winnowing them (both on the first day and last).