Malting Barley
With the exception of crops grown for seed, malting barley is the only crop that has to be delivered to the customer in a living state. This means that malting barley production requires much greater care and management than other commercial crops.
Malting barley is the primary ingredient in the processing of beer. The process has two basic steps:
- the biological conversion of barley to malt at the malt house, and;
- the biological conversion of malt and other ingredients into beer at the brewery.
The steps appear to be simple but are actually quite technical, especially the brewing process, and requires a balance of art and science. Brew masters will use years of experience, proprietary ingredients and recipes for a targeted end-product.
The malting and brewing processes adhere to strict quality and production standards. Many of the malting barley quality characteristics required by maltsters are under the control of producers, while others are weather related. As is often the case with grain production, a combination of cultural and environmental aspects determines the end-quality of the product.
According to the Brewing and Malting Barley Research Institute (BMBRI), the following characteristics are required in superior malting barley:
- Pure lot of an acceptable variety
- Germination of 95 per cent or higher (three-day test)
- No signs of pre-harvest germination
- Protein content of 11 to 12.5 per cent (dry basis)
- Moisture content to a maximum of 13.5 per cent
- Plump kernels of uniform size
- Fully mature
- Free from disease
- Free of DON mycotoxin caused by fusarium head blight
- Free from frost damage
- Not weathered or deeply stained
- Less than 5 per cent peeled and broken kernels
- Free from heat damage
- Free of insects, admixtures, ergot, treated seeds, smut and odour
- Free of chemical residue
These requirements will affect both the malting and brewing processes, as well as the quality of the end-product, beer.
General recommendations for malting barley production
Variety selection
Selecting a variety for its agronomic performance and marketing potential is the first step in producing a marketable malting barley crop. Malting and feed types of barley have different quality profiles which result in different products when malted and brewed. In fact, each malting variety has a unique quality profile. Since different types of beer require different quality profiles in the malt, brewers will specify which varieties they require. Therefore, it is necessary for producers to plant, store and ship varieties separately. Also, since varieties respond differently in the malting and brewing processes, familiarity with the variety allows the brewer to use a recipe that will ensure a unique and consistent end-product.
The Canadian Malting Barley Technical Centre provides a list of recommended malting barley varieties. Additionally, producers should contact grain and malting companies to explore market potential for the various varieties.
Seed
The seed lot should be true to variety, have high germination with strong vigour and be free of disease and weed seeds. Using certified seed, and possibly treating the seed if sowing into cool soils, will get the crop off to a good start.
Timing of seeding
The timing of seeding can affect protein and overall quality. Early seeding is generally recommended for a number of reasons. Early seeded crops tend to mature before soil moisture levels become depleted, thereby increasing the likelihood of producing plump and uniform kernels. Another advantage of early seeding is that the harvest can generally occur during dry conditions, avoiding cool wet falls and the likelihood of weathering and pre-harvest sprouting. Early seeding can also play a role in disease avoidance.
Field selection
Select relatively uniform fields to obtain even maturity. If patchiness does occur, these areas could be harvested separately. Proper crop rotations will lessen disease pressures and avoid volunteer seed issues.
Seeding rate and depth
Depending on the region, the target plant density should be from 18 to 25 plants per square foot (195 - 270 plants per square metre). Producers must account for the rate of germination and seedling mortality. The Alberta Agriculture and Irrigation seeding rate calculator provides a convenient method to determine the seeding rate.
Seeding depth should be approximately 1.5 to 1.75 inches. (3.8 to 4.5 centimetres). Although having the seed in contact with moist soil is important, placing the seed below two inches (five cm) is not recommended. Deep seeding can result in weak plants, reduced emergence and vulnerability to root and seedling diseases.
Fertility
Prairie soils are often deficient in nitrogen and phosphorus. Some soils are also deficient in potassium, sulphur and possibly one or more micronutrients. Soil testing will provide a good gauge of nutrients for proper crop production in your region.
Nitrogen is the major nutrient promoting plant growth and yield. It is often the yield-limiting nutrient in crop production in the Prairies. Phosphorus is necessary for plant growth and is required in large amounts by the plant. Phosphorus is needed throughout the growth stages of the plant, but is especially important at the early growth stages. Adequate phosphorus will improve crop quality, root growth and time to maturity. Plants also need large amounts of potassium, which play a key role in many physiological processes vital for plant growth. Potassium helps reduce disease and improves straw strength.
A well-balanced fertility program is important for producing good yields and acceptable quality. Provided other factors are not limiting, protein and yield are mostly determined by the amount of precipitation and available nitrogen. Given the same amount of available nitrogen, high levels of precipitation will lower protein, while drier conditions will result in higher protein.
A dilemma for producers is to balance the nitrogen requirement to maximize yield, while maintaining low protein levels. Protein content and yield will increase with increased rates of nitrogen. However, protein increases at a slower rate than does yield. Protein levels outside the desired range can cause problems in the malting and brewing process. High protein levels, for example, will reduce the amount of fermentable material (malt extract) and can cause brewing issues such as cloudiness in the beer. In general, lower protein is better than higher protein for most markets, and marketers are willing to pay for lower protein. However, protein content lower than 11 per cent is not desirable.
Disease control
Fields should be monitored for leaf diseases. If economically warranted, registered fungicides will help minimize yield loss and maintain kernel plumpness. The timing of fungicide application is critical - follow the label carefully. Adhering to recommended cropping rotations will minimize the risk of soil-borne diseases. The potential for seed- borne diseases, such as smut, can also be minimized by using registered seed treatments when necessary.
Swathing versus straight combining
Both straight combining and swathing can produce marketable malting barley. Desiccants and harvest aids such as pre-harvest glyphosates are not allowed for malt barley production. Swathing should be delayed until the moisture content is below 30 per cent. At this stage, the barley kernel is difficult to dent with your thumbnail.
Standard recommendations for swathing versus straight combining barley are not common. Generally, time and quality management, equipment availability, and personal preference will determine whether or not producers swath or straight combine. However, there is a trend to straight combining, which will likely continue.
General advantages of swathing
- Protection against shattering. This is particularly true for crops with a higher tendency to shatter, such as six-row barley. However, to protect against sprouting and staining, it is recommended to leave the crop standing as long as possible.
- Hastens dry-down, given proper drying conditions in the swath. Terminating plant growth can result in a shorter time interval to harvest. This can be beneficial on rolling land with uneven maturity, since producers may not want to risk shattering losses while they wait for later maturing areas to dry down.
- Terminates under-story growth (late flushes of tillers, volunteers and weeds).
- Offers the opportunity, if you have a thin stand, to create a double swath to better utilize combine capacity.
- Offers a strategy to deal with lodging.
The advantages of straight combining are generally related to time management, as well as quality management, especially during wet fall conditions.
- Protection against sprouting and staining. Most malting barley varieties, especially two-row varieties, are susceptible to sprouting.
- If the grain is tough, it will dry faster in the head than in the swath, resulting in better quality and shorter time to harvest.
- Heavy dew will affect grain quality (sprouting, staining) in the swath more than standing grain.
- Provides one operation; however, if areas of the field are still a bit green, producers may harvest around these areas to protect quality, resulting in additional trips to the field.
Harvesting and handling
Combining can begin at 16 per cent moisture if aeration is available. Peeling can occur if the grain is too dry. If it is too wet, storage and germination concerns can occur. If aerating, start early (i.e. after a few loads). The fan should continue to operate until the process is complete. If the fan is turned off for longer than a few hours, a crust can develop in the bin, preventing sufficient air flow when aeration continues. It is generally preferred not to use heat, but if necessary, drying should occur slowly, at low temperatures with large volumes of air. Drying with excessive heat can affect germination, which negatively affects the malting process. To prevent heating within the bin's core, the drying process should include a cooling period, which will reduce the bin temperature. If possible, continuous drying is better than batch drying.
If the moisture content falls below 13.5 per cent, peeling during combining and handling is more likely. Therefore, producers should adjust the combine (cylinder/rotor speed and concave clearance) and handling equipment so peeling and breakage are minimized. Producers will want to check the sample regularly and may want to adjust the combine throughout the day as grain moisture and humidity change. Maltsters prefer kernels with a small piece of intact awn.
Storage conditions should maintain low moisture levels. Bins should be clean and dry.
Handling should be minimized to reduce peeled and broken kernels. It is recommended to run augers at a slower speed and at full capacity.
Proper sampling is also very important. Samples should be collected (a five-gallon or 22.7-litre pail works well) when filling the bin, and should represent the entire bin. Sampling should be done from different places in the grain stream, such as the front, back and side, since grain and weed seeds of different density will be in greater proportion in different parts of the stream. The sample should be labelled with variety name, field and bin number and stored in a cool, dry place. Harvests of different varieties, and even different weather conditions, should be stored separately.
Producers who sow malting barley varieties are generally hoping to capture the malt premium. The above recommendations will help produce high-quality malting barley.
For more information:
Written with the assistance of Dr. Brian Rossnagel, University of Saskatchewan and Michael Brophy, Brewing and Malting Barley Research Institute.