Proper dry bean storage management is important to prevent a grade decrease.
Box storage can be safely undertaken at 17% seed moisture or less.
Although dry beans are considered dry at 12 -16% seed moisture. If moisture drops too low cracking becomes an issue. Waiting until moisture increases in the evening or early morning may be necessary.
Extra care should be taken to monitor dry bean after being in storage for moisture build up or spoilage. Monitor regularly for hot spots and other changes in moisture and temperature. A variety of manual and automated systems are available to help keep track of seed condition.
HEATED GRAIN DRYING OR AERATING DOWN
Dry bean must be dried and conditioned carefully.
Dry beans are often traded at 17% moisture but are considered dry at 16% moisture. Discounts for beans below 15% moisture may be applied. Dry beans are considered damp at ≥18.0%.
Dry bean must be dried slowly using low temperatures for heated air dryers and optimum relative humidity for natural air drying systems. Over-drying increases the chance of splitting, cracking and handling damage, while drying too slowly increases the risk of mould and insect invasion.
Aeration fans can be used to reduce moisture of beans harvested at 18% to 22% moisture, but care should be taken to avoid over drying.
Some companies will take delivery directly from the combine to avoid damage from extra handling.
If storing and hauling at later dates, care should be taken not to handle beans at very cold temperatures (less than -20°C), as the risk of cracking will increase
Latest research: Improved Management of Stored Pulses, Research Update, August 2019, PAMI
MAKING THE GRADE
Grading is done by the Canadian Grain Commission. Through the harvest sample program, farmers have the opportunity to send in harvested samples to the Grain Commission for grading. This grade can be compared with local buyer grades and may assist in marketing.
Dockage is determined on 1 kg sample sizes, sieving samples, using approximately 250 g at a time, to remove all readily removable material.
The sample is sieved over the appropriate slotted hand sieve (No. 8, 9, and 11 slotted) and hand-picked to remove all coarse foreign vegetable matter such as pods, stems, straw, and thistle tops. It does not remove mineral matter, ergot, sclerotia, weed seeds or other grains.
Primary samples are considered commercially clean when they contain no dockage material.
COLOUR AND SIZE
Colour and uniformity of size are important factor in grading of dry beans, as they are a measure of “standard of quality”.
Colour is evaluated on the cleaned sample after the removal of splits and damaged bean.
Good natural colour: beans may be slightly dull, slightly immature or have lightly adhered soil. To obtain a grading of Extra No. 1 Canada they need to have uniform size and good natural colour.
Reasonably good colour: beans are moderately immature, with lightly adhered soil, or are lightly stained, or are lightly discoloured from storage. Graded as No. 1 Canada.
Fairly good colour: beans have moderately adhered soil or are stained, or moderately discoloured from storage. Can be graded as Canada No. 1 Select, No. 2 or No.3 Canada (depending on other factors).
Off colour: beans cannot be considered of fairly good colour. Graded as No. 4 Canada.
Sunburned or oxidized – In assessing colour which does not meet grade standards, the term “Sunburned or oxidized” may also be used. This is the normal discolouration of the seed coat during storage. The colour may vary from light tan to brown or very dark brown, depending on the duration and conditions of storage. The colour is assessed against the standard print for the grade.
Contrasting Beans: Beans of another class that is of a contrasting colour, size and/or shape to the predominant bean in a sample is considered to be a contrasting class.
Samples containing contrasting classes in excess of the tolerance for the lowest numerical grade are graded “Bean, Sample Canada (class), Account Contrasting Classes”.
Other classes that blend are sound beans of other classes which are similar in colour, size and shape to the predominant beans in a sample.
Samples containing bean of other classes that blend in excess of the tolerance for the lowest numerical grade is graded “Bean, Sample Canada (classes), Account Other Classes That Blend”.
Damaged beans include:
Whole, split, or broken beans that are sprouted, very immature, perforated, distinctly deteriorated or discoloured by weather or disease.
Beans that are otherwise damaged in a way that seriously affects appearance or quality. This includes mudball beans in processed beans, which are beans that are completed covered in adhered soil.
Adhered soil is unprocessed pea bean densely covered with adhered soil (often referred to as mud balls) that will ultimately be removed in processing are assessed as dockage; in processed samples, pea bean is considered damaged.
Splits include split bean, broken pieces of bean less than three quarters of whole kernels, and halves of beans that are loosely held together by cracked seed coats. Cracked seed coats are considered sound if the halves are firmly held together and the bean is otherwise undamaged.
The procedure for splits including using a slotted sieve to help separate splits. Return to the sample any whole beans which pass through the sieve.
Magnesium spot is a black spot penetrating the cotyledon, most commonly found in cranberry beans. Affected beans are considered damaged.
Odour – There is no numeric tolerance for odour. Consider the basic quality of the sample; the type and degree of the odour, and the presence of visible residue causing the odour.
An objectionable odour, not heated or fireburnt – graded as “Beans, Sample Canada Account Odour”.
A heated odour, graded as “Beans, Sample Canada Account Heated”.
A fireburnt odour, graded as “Beans, Sample Canada Fireburnt”.
DAMAGED – HEATED, ROTTED AND MOULDY
Heated, rotted and mouldy are considered in the same tolerance, and will be combined with other types of damage and included in the specification for total damage.
Heating in pea bean: indicated by a dull seed coat varying from cream to mahogany colour. The colour is more intense in the hilum area. When viewed in cross-section, the cotyledons vary in colour from tan to dark brown. Very light cotyledons are considered damaged rather than heated.
Heating in red kidney bean: indicated by a dull seed coat, dark red to black colour. To determine the degree of damage, split the bean. Do not cut it crosswise. Heated seeds of other grains are included in the tolerance for heated.
Rotted bean: whole beans or pieces of beans that are visibly in advanced stages of decomposition and feel spongy under pressure.
Mouldy: characterized by the presence of dark blue exterior moulds that develop in machine-damaged crevices. Light and dark red kidney beans may develop yellow to black interior moulds in the concave centre area.
Bean containing more than 1.0% by weight of heated, rotted and/or mouldy bean, or having a heated or musty odour are graded “Bean, Sample Canada (class), Account Heated” or “Account Mouldy Kernels”; samples with a fire burnt odour are graded “Bean, Sample Canada (class), Account Fire Burnt”.
This includes any material other than beans or split beans not removed in cleaning.
These materials could include adhered soils, earth pellets (soft), earth pellets (hard) are considered stones, shale, or similar material, ergot and sclerotia not removed in cleaning.
Hard earth pellets are pellets or stones that do not crumble under light pressure.
Soft earth pellets are pellets that crumble under light pressure. These pellets can be earth and fertilizer pellets, or any non-toxic material of similar consistency.
Stones are hard shale, coal, hard earth pellets, and other non-toxic materials of similar consistency. Stones are handpicked from a representative portion of the cleaned sample, and the stone concentration is determined in the net sample.
Fertilizer pellets are assessed as stones when constituting 1.0% or less of the net sample weight.
Stones between 0.0% (Extra No.1 Canada) to 0.50% (No. 4 Canada) can be graded in the regular grades.
At 1% stones:
In western Canada graded “Beans, Rejected No. 2 Canada (name of bean) Account Stones”;
In eastern Canada 1% stones is graded “Beans, Sample Canada (name of bean) Account Stones”.
At 2.5% stones:
In western Canada beans are graded “Beans, Rejected “basic grade” Account stones”.
In Eastern Canada beans are graded “Beans, Sample Canada Account Stones”.
At > 2.5% stones, in both western and eastern Canada, beans are graded “Beans, Sample Salvage”.
Ergot is a plant disease producing elongated fungal bodies with purplish-black exterior, a purplish-white to off-white interior, and a relatively smooth surface texture.
Excreta is excrement from any animal including mammals, birds, and insects.
Insect parts – refers to pieces of insects such as grasshoppers and lady bugs that remain in the sample after cleaning or processing.
Samples are analysed for the percentage of insect fragments and graded according to established tolerances.
Insects may also result in seed staining and earth adhering to the seed and may result in samples having an objectionable odour.
Samples containing staining will be considered to be earth tagged and grading according to colour definitions.
Sclerotinia sclerotiorum is a fungus producing hard masses of fungal tissue, called sclerotia. The sclerotia vary in size and shape, have a coarse surface texture, vary in exterior colour from dark black to gray to white and have a pure white interior.
Contaminated is defined in the Canada Grain Act as; “Contaminated means, in respect of grain, containing any substance in sufficient quantity that the grain is unfit for consumption by persons or animals or is adulterated within the meaning of the regulations made pursuant to sections B.01.046(1), B.15.001 and B.15.002(1) of the Food and Drugs Act.”
Samples deemed to be contaminated by the Grain Research Laboratory in consultation with the Chief Grain Inspector for Canada are graded Beans, Sample Condemned.
EARTH TAG MANAGEMENT
Earth-tag seed (soil stains on seeds that cannot be removed) are very undesirable for marketing.
To reduce earth tag in dry bean, follow these management tips:
Select a variety with a good harvest rating.
Roll your dry beans just after seeding, to eliminate ridges and an uneven seed bed, as this approach will minimize dirt entering the combine (normal plant dust will not adhere to a dry bean seed coat, but combined soil will).
Use a desiccant at 30% grain moisture content to even out crop drydown and eliminate green weed material. Green material is either green weeds or green dry bean plant material that will increase the level of earth tag on the seed. Prior to applying desiccant, check with Keep it Clean to mitigate risk.
Combine when seed moisture content reaches 18% to 22%.