Buyers of durum have a large array of quality options from which to select via their contract specifications. To acquire the quality desired, it is important to understand the options available. These options include:
As described elsewhere in this website, U.S. grades 1-5 and Sample Grade are determined by test weight, percentage of defects (damaged kernels, shrunken and broken kernels, and foreign material) and the percentage of wheat from other or contrasting classes. Typically, most buyers of U.S. durum specify No. 2 or better.
In this case, the class of wheat is durum, with subclasses controlling for hard, vitreous kernel content. Subclass options include:
Hard Amber Durum (HAD) with more than 75 percent vitreous kernels,
Amber Durum (AD) with 60 to 74 percent vitreous kernels, and
Durum (D) with less than 60 percent vitreous kernels.
Most buyers prefer hard amber durum (HAD).
Quoted on a 12 percent moisture basis. Protein specifications have recently become more important in durum contracts due to labeling requirements on the finished product, especially in the United States. Most buyers specify a minimum of 12 or 13 percent protein.
Moisture content-Maximum moisture content options include: 13.5% 13.0% 12.5% 12.0%
Maximum limits may be placed on specific types of damage (sprout, frost, disease or insects).
Examples may include:
1.0% 0.5% 0.4% 0.2% 0.1% 0.0%
Generally a minimum of 300 seconds but some will specify 350 seconds.
Options may include:
FN minimum 300 cargo composite
FN 300 sublot average
FN 300, no sublot under 300
Foreign material and shrunken and broken kernels are the three major components impacting the cleanliness or purity of a sample. Dockage is not included as a grading parameter and needs to be specified separately. If you want tighter specifications for foreign material and shrunken and broken kernels, than the limits defined by the grade, then you also need to add those specifications to the contract.
Dockage options include:
Maximum dockage, all deductible from contract weight
Maximum dockage, all deductible with reimbursement for freight and insurance on dockage
Maximum dockage, with cash discount applying above a certain level
Contract Specification Basics
Buyers need to be aware of actual production quantities and qualities when setting contract specifications for durum. Durum production is concentrated to a smaller geographical area than other classes of U.S. wheat, which puts the crop at an increased risk from adverse weather. There is no good substitute for durum in the production of premium pasta, so the market is highly sensitive to changes in quality from year-to-year. Price premiums and discounts for quality factors, such as vitreous kernel content, test weight, and total defects can be significant.
If premium, durum pasta is the end-use desired, then you may wish to use tighter specifications for vitreous kernel levels, falling number, test weight and total defects. On the other hand, if total extraction is more important than semolina extraction, and a bright, yellow color is not vital , you may be able to obtain a lower price by using more relaxed specifications.
Examples of specifications which may be used:
U.S. grade No. 1, minimum 85% hard vitreous kernels
Moisture, maximum 12%
Maximum shrunken and broken kernels 1.0%
Falling number 325, no sublot below 300 seconds
Protein, minimum 13.5%, no sublot below 13.2% ( 12% moisture basis)
Dockage, maximum 0.7%, all deductible from contract weight with reimbursement for freight and insurance on dockage
U.S. grade No. 2, Hard Amber Durum (HAD) or better
Damaged Kernel content, maximum 3%
Sprouted Kernels, maximum 0.5%
Moisture, maximum 13.0%
Falling number, 250 average, no sublot below 225 seconds
Protein, minimum 13.2% average (12% moisture basis)
Dockage, maximum 1% average, all deductible
Note: The North Dakota State University Cereal Science Department in 1999 initiated a study of the relationship between falling number and the quality of durum wheat and pasta. Preliminary results indicate preharvest sprouting and subsequent amylase activity (as measured by falling number) does not have significant effect on milling or pasta quality as long as the protein content of the durum is sufficient and damaged kernel content is limited. For more information, contact Jim Peterson, North Dakota Wheat Commission.