U.S. Wheat Glossary of Terms

Buying Terms

C&F (Cost and Freight). Seller provides the cargo, covers the loading costs and charters the ocean vessel for a specific destination. The buyer must pay for insurance and for discharge of the grain from the vessel. Buyer specifies shipment period.

CIF (Cost, Insurance, Freight). Seller provides the cargo, covers the loading costs and charters the ocean vessel, plus insures the cargo until it reaches its destination. Seller determines the final loaded quantity within the contract quantity tolerance; the buyer pays for discharge. Buyer specifies shipment period.

FOB (Free on Board). Seller is responsible for placing grain at the end of the loading spout. Buyer is responsible for providing the ocean vessel, and for all other costs after the grain is delivered on board, including stowing and trimming the cargo in the holds. Buyer determines the final loaded quantity within the contract quantity tolerance. Buyers specify delivery period.

Grain Inspection, Packers and Stockyards Administration (GIPSA). An agency within the U.S. Department of Agriculture that provides farmers, handlers, processors, exporters, and international buyers with information and tools that accurately and consistently describe the quality and quantity of the grain and commodities being bought and sold by:

• Providing the market with terms and methods for quality assessments. The Official U.S. Standards for Grain are used each and every day by sellers and buyers around the world to communicate the type and quality of grain bought and sold. Our standard testing methodologies accurately and consistently measure grain quality.
• Providing traditional and innovative inspection and weighing services to the traditional bulk and specialty commodity markets.
• Managing the national inspection and weighing system, a unique network of Federal, State, and private laboratories that provide impartial, user fee funded official inspection and weighing services.
• Providing international services and outreach programs that keep America's grain flowing to our international customers.
• Protecting the integrity of the official inspection system and the market at large to ensure markets for grain and related products are fair, transparent, and free from deceptive and fraudulent practices.

Federal Grain Inspection Service (FGIS). As part of GIPSA, FGIS oversees impartial inspectors who sample, weigh, inspect, and certify nearly every single wheat shipment exported from the U.S.

Letter of Credit. The most common form of payment for U.S. wheat, in which the buyer's bank first establishes a letter of credit in favor of the seller. When the grain is shipped and documentation is presented, the seller's bank makes payment to the seller, then the buyer's bank makes payment to the seller's bank. A letter of credit greatly reduces commercial risk for the seller, but involves higher bank service charges.
More. Click here to learn more about the U.S. grain export marketing system.

Quality Testing Terms

Wheat Grades. The physical quality and condition of a sample and thus may indicate the general suitability of a sample for milling. The U.S. grade of a sample is determined by measurement of such factors as test weight, damaged kernels, foreign material, shrunken and broken kernels, and wheat of contrasting classes. All numeric factors other than test weight are reported as a percentage by weight of the sample. Grade determining factors include:

• Test Weight. A measure of the density of the sample and may be an indicator of milling yield and the general condition of the sample, as problems that occur during the growing season or at harvest often reduce test weight.
• Damaged Kernels. Kernels which may be undesirable for milling because of disease, insect activity, frost or sprout damage, etc.
• Foreign Material. Any material other than wheat that remains after dockage is removed. Because foreign material may not be removed by normal cleaning equipment, it may have an adverse effect on milling quality.
• Shrunken and Broken Kernels. Kernels which either were insufficiently filled during growing and have a shrunken or shriveled appearance or have been broken in handling. Such kernels may reduce milling yield.
• Total Defects. The sum of damaged kernels, foreign material and shrunken and broken kernels.
• Vitreous Kernels. In hard red spring wheat, kernels which are uniformly dark and have no spots which appear chalky or soft. In durum, vitreous kernels have a glassy and translucent appearance without any spots that appear chalky.

Dockage. The percentage by weight of any material easily removed from a wheat sample using the Carter Dockage Tester. Dockage, because it can be easily removed, should not have any effect on milling quality but may have other economic effects for buyers. Grade factors are determined only after dockage is removed.

Moisture Content. The percentage moisture by weight of a sample and is an important indicator of profitability in milling. Flour millers add water to adjust wheat moisture to a standard level before milling. Lower wheat moisture allows more water to be added, increasing the weight of grain to be milled at virtually no cost. Moisture content is also an indicator of grain storability as wheat and flour with low moisture are more stable during storage. Because moisture can be readily added to or physically removed from a sample, other analysis results are often mathematically converted to a standard moisture basis, such as 14%, 12% or dry matter, so results can be meaningfully compared.

Protein. The percentage protein by weight in a sample. Protein can be quickly and easily measured and therefore is an important factor in determining the value of wheat since it relates to many processing properties, such as water absorption and gluten strength. Low protein is desired for products such as snacks or cakes. High protein is desired for products such as pan breads, buns and frozen yeast-raised products.

Ash Content. The percentage of minerals by weight in wheat or flour. In wheat, ash is primarily concentrated in the bran and is an indication of the flour yield that can be expected during milling. In flour, ash content indicates milling performance by indirectly revealing the amount of bran contamination in flour. Ash in flour can impart a darker color to finished products. Products requiring particularly white flour call for low ash content while whole wheat flour has higher ash content.

1000 Kernel Weight. The weight in grams of one thousand kernels of wheat and may indicate grain size and expected milling yield.

Kernel Size. A measure of the percentage by weight of large, medium and small kernels in a sample. Large kernels or more uniform kernel size may help improve milling yield.

Single Kernel Characterization System (SKCS). Measures 300 individual kernels from a sample for size (diameter), weight, hardness (based on the force needed to crush) and moisture. Detailed SKCS results (not reported in this booklet) include the distribution of these factors, which may be an indicator of the uniformity of the sample and may help millers experienced with the system optimize flour milling yields. Kernel characteristics are related to milling properties such as tempering, roll gap settings, and flour starch damage content.

Sedimentation Value. A measure of the sediment that results when lactic acid is added to a sifted ground wheat sample and can be used as an indicator of gluten quality and thus the baking quality of wheat flour.

Falling Number. Indirectly indicates alpha-amylase activity, which results from sprout damage. High Falling Number values indicate low alpha-amylase activity. Sufficient alpha-amylase activity is required in flour for some products such as yeast-raised bread. However, excessive alpha-amylase in wheat cannot be removed and is difficult to blend to lower alpha-amylase content, and the resulting flour produces a sticky dough that can cause problems during processing and products with poor color and weak texture. Falling Number usually correlates closely with amylograph.

Extraction. The percentage by weight of flour obtained from a wheat sample. In a commercial flour mill the extraction rate is critically important to mill profitability. In a laboratory, milling with the Buhler Laboratory Mill is mainly done to obtain flour for other tests. The Buhler Laboratory Mill extraction rate is always significantly lower than the rate that can be obtained on a commercial mill, but may be useful for comparison between crop years.

Color. A numerical system to measure a sample’s lightness (L*) on a scale of 0 to 100 and “chromaticity” or hue on two scales each running from -60 to +60 for green-red (a*) and blue-yellow (b). High L* values indicate a bright color, and higher b* values indicate more yellow. Flour color is influenced by the wheat’s endosperm color and the ash content of the flour and often affects the color of the finished product.

Wet Gluten. A measure of the quantity of gluten in wheat or flour samples as determined using the Glutomatic system. Gluten forms when water is added to the protein in wheat and is responsible for the elasticity and extensibility characteristics of flour dough.

Gluten Index. Also determined by the Glutomatic system and is a measure of gluten strength regardless of the quantity of gluten present. Gluten index is used commercially to select durum samples with strong gluten characteristics while its usefulness for bread wheat samples is less clear because of the variety of factors other than gluten that can affect the results.

Amylograph. Measures flour starch pasting properties that are important to some end products such as sheeted Asian noodles. Amylograph also measures enzyme (alpha-amylase) activity which results from sprout damage. Amylograph results usually correlate very closely with Falling Number results.

Starch Damage. Is the percentage by weight of damaged starch in a flour sample, a measure of the physical damage done to starch granules during milling. Bread (hard) wheat flour typically has higher starch damage than soft wheat flour. Highly damaged starch readily absorbs more water which affects dough mixing and other processing properties. Because starch damage depends on how the sample was milled, starch damage is important for interpreting other results reported.

Farinograph. Generates a curve that indicates the power being used over time as flour and water are mixed into dough. The results describe the mixing properties of the dough and include:

• Peak Time. The time interval from the first addition of water to the maximum consistency immediately prior to the first indication of weakening. Long peak times indicate strong gluten and dough properties while short peak times may indicate weak gluten.
• Stability. The interval between the point where the top of the curve first intersects the 500-BU line (called the “arrival time”) and the point where the top of the curve departs the 500-BU line (“departure time”). Long stability times also indicate strong gluten and dough properties, useful in such products as yeast-raised breads while short stability times indicate weaker gluten useful in many confectionary products.
• Absorption. The amount of water (as a percent by weight of 14 percent moisture wheat flour) required to center the curve peak on the 500-BU line. High water absorption provides economic advantages for producing more dough pieces than flour with lower water absorption.
• Classification. Rates the curves produced by the farinograph (”farinograms”) on a scale of 1 to 8, with higher values indicating stronger gluten and dough mixing properties for hard red spring wheat flour.

Alveograph. Generates a curve indicating the air pressure necessary to inflate a piece of dough like a bubble to the point of rupture and indicates the gluten strength and extensibility of dough. Values reported include:

• P (“overpressure”), measured in millimeters to the maximum height of the curve, reflects the maximum pressure while blowing the bubble of dough and indicates dough resistance to extension.
• L (length), the length of the curve measured in millimeters, reflects the size of the bubble and indicates dough extensibility.
• W (the area under the curve) reflects the amount of energy needed to inflate the dough to the point of rupture and indicates dough strength.

The alveograph is well suited for measuring the dough characteristics of weaker gluten wheat. Flour with low P value (indicating weak gluten) and long L value (high extensibility) is preferred for cakes and confectionery products. Flour with high P values (strong gluten) is preferred for breads.

Extensograph. Generates a force-time curve for a piece of dough stretched until it breaks. Results include:

• Resistance, measured at the maximum curve height in Brabender units (B.U.), reflects the maximum force applied and indicates the resistance of the dough to extension.
• Extensibility, measured as the total length of the curve at the base line in centimeters, reflects how far the dough was stretched.
• Area is the area under the curve reported in square centimeters.

These factors help describe the gluten strength and dough extensibility characteristics of flour for a wide range of end products. The extensograph can also evaluate the effects of fermentation time and additives on dough performance.

Mixograph. A similar instrument to the farinograph but quicker and using a smaller amount of flour sample, that generates a graph recording the force needed to mix flour or semolina and water into dough. The graph is classified on a scale of 1 to 8, with higher values indicating stronger gluten characteristics for durum milled fractions.

Solvent Retention Capacity (or SRC). The weight of solvent held by flour after centrifugation, and expressed as a percent of the flour weight on a 14 percent moisture basis. The different solvents used relate flour functionality to specific flour components and thus can be useful for predicting commercial baking performance, especially for soft wheat flours.

Baking Absorption. The water required for optimum dough mixing performance, expressed as a percent of flour weight on a 14 percent moisture basis.

Crumb Grain and Texture. Determined on a scale of 1 to 10 by visual comparison to a standard using a constant illumination source. Higher scores are preferred.

Loaf Volume. The volume of the test loaf after baking. Higher loaf volumes indicate better baking performance for pan breads.

Specks. Visually counted in a semolina sample and reported as the number in 10 square inches. Specks, which can detract from pasta appearance and desirability, are small particles of bran or other material that escaped the wheat cleaning and semolina purifying process and thus depend on the milling process as well as the characteristics of the durum.

Standardized Baking Tests. Includes the Sugar Snap Cookie, Sponge Cake, Chinese Southern-Type Steamed Bread, Spaghetti, and the Hard White noodle and steamed bread tests, using standardized methods to prepare specific end products to evaluate the suitability of the sample for that product or similar products.