Oilseed Processing for ATTRA Small-Scale Producers A Publication of ATTRA - National Sustainable Agriculture Information Service • 1-800-346-9140 • www.attra.ncat.org By Al Kurki, Janet There are many varieties of seeds and nuts that can produce oils for food, nutraceuticals, skincare prod- Bachmann and Holly ucts, aromatherapies, fuels and industrial lubricants. This publication describes the basic processes Hill, NCAT Agriculture involved in oil processing including seed cleaning, extraction, clarification, packaging and storage. Specialists Sources for more information and equipment are included in the References and Resources sections Lakeitha Ruffin and at the end of the publication. Byrhonda Lyons, NCAT Interns Matt Rudolf, plant-derived oils can be used to make soap, Piedmont Biofuels body and hair oils, detergents and paints. Cooperative Some can also be used to make industrial © 2008 NCAT lubricants. A wide range of oilseeds and other oil-producing plants are high-quality Contents feedstocks for biodiesel. Oilseed processing Introduction ..................... 1 expands the use of crops such as sunflowers Getting started ............... 1 and brings value to grape seeds, which are Basic processing usually waste products. steps ................................... 2 Most oil processing in the United States Oilseed by-products: Meal and hulls ................ 6 is done on a large industrial scale. Small- Adding value scale oil extraction is more commonplace in adds costs ......................... 7 other parts of the world. As a result, many References ........................ 9 of the useful resource materials and much Resources .......................... 9 of the appropriate-scale machinery come from other countries. However, interest in small- to intermediate-scale oilseed process- ing on the part of farmers and others in the United States grew dramatically in the past Photo courtesy Sustainable Systems, LLC five years. This publication describes the Safflower oil. basic processes of oilseed production, with extensive sources for additional information Introduction and equipment. Farmers and small business owners are asking if it is possible and profitable to add Getting started value to their seeds and nuts by extract- Culinary oil businessman and consultant ing the oil. This is not an easy question to E. Peter Matthies, now living in Germany, answer because there are so many vari- suggests that you ask yourself the following ATTRA—National Sustainable ables, some of which are noted in the fol- questions before starting oil processing: Agriculture Information Service lowing sections of this publication. is managed by the National Cen- • Why do I want to start oil processing? ter for Appropriate Technology Culinary oils include olive, sesame, saf- (NCAT) and is funded under a • Will it be a hobby or a new economic grant from the United States flower, sunflower, grape seed, canola, enterprise? Department of Agriculture’s Rural apricot kernel, coconut, hazelnut, peanut, Business-Cooperative Service. Visit the NCAT Web site (www. pumpkin and walnut oils. Advertisements • How big will the operation be? ncat.org/sarc_current. for these culinary oils tout their health php) for more informa- • How many different products will be tion on our sustainable benefits and unique flavors. Some of these made, including both oil and the press agriculture projects. cake left after the oil is pressed out of • Clean. Fine dust in the seed may clog the raw seeds or nuts? the oil press hardware. Chaff left in the • Do I want to target mass markets or spe- seed will absorb some of the oil and cialty markets? keep it from getting squeezed out of the expeller. Sand in the seed will wear out • What geographical area do I want to the press. Stones damage the oil press cover? screw or piston. The first question is important because it • Dry. Moist seed leads to low yields and affects the answers to all the other ques- clogs the screw or cage, a part of the tions. It even affects how you read this pub- press. Moist seed may also get moldy, as lication. If you crush oilseeds for biodiesel mold spores are present in all crops. A or straight vegetable oil fuel production, you rule of thumb is that the moisture content need to pay special attention to several spe- of the seed should be close to 10 per- cific processing steps. cent. The number varies considerably for For culinary oils, there are several more specific oilseeds. For example, rapeseed processing steps and technologies to con- should be dried to a 7-percent moisture sider and possibly add to your plan. You content, camelina to about 6 percent and may forego some of the more complex, sunflower to 8.5 percent. Safflower needs costly steps for exclusively personal-use only to be dried to 11 percent and soy- cooking oil or biofuel. bean is safe for storage and processing at 12 percent (Alam, 2007). Later in this publication, Matthies describes how he got into this new oil business after There are at least two methods of testing retiring from the petroleum business. seed moisture levels. Hand-held moisture testers allow the user to simply place the seed in the tester, turn it on and select Basic processing steps the type of seed to test. The tester pro- vides an instant readout. These testers Seed cleaning cost from $400 to $700. Brand names Preparation of the raw material often include DICKEY-johns mini GAC, the includes removing husks or seed coats Graintec HE-50 and GE Sensing’s Pro- from the seeds and separating the seeds timeter Grainmaster. from the chaff. There are a wide variety of This canola seed will small- to intermediate-scale approaches to Here is a lower-tech, low-cost way of need very little cleaning and technologies for effective seed clean- moisture testing: Weigh a sample of before crushing. ing. Approaches range from seed, and then heat the sample in an using various sizes of hard- oven at 300 degrees Fahrenheit for one ware cloth screens in tandem hour. Reweigh the sample. The weight (Clothier) to using a compact lost in the oven is equal to the moisture fanning mill such as the Clip- content of the original sample. Calculate per Office Tester and a spi- the percentage by dividing the weight ral separator for small farms lost by the original weight and multiply- (Small Scale Grain and Pulse ing the result by 100. Production forum, 2008). Even dry seed can quickly get damp by See the Resources sec- being in contact with damp earth. Once tion for examples, types and the seed is dried and bagged, it must be sources of equipment. carefully stored to keep it from absorbing moisture. Seed preparation and • Warm. Warm seed will yield the most conditioning oil for the least effort. The optimum heat For successful pressing, the range for oil extraction is from 100 to Photo by Holly Hill, NCAT seed must be: 160 degrees. There are several ways to Page 2 ATTRA Oilseed Processing for Small-Scale Producers preheat the seed in advance of extrac- example, the Täby Press is a screw press tion. For very small batches, heating the manufactured in Sweden. It is similar to seed in an oven or double boiler works, the Komet Oil Expeller described below. as does concentrated sunlight in a solar Various models are available for cold press- food dryer or some other solar collector. ing rapeseed, linseed, flaxseed, sunflower For larger batches, a heating element in seed, sesame seed, peanut, groundnut, a hopper located between the seed stor- mustard seed, poppy seed, cotton seed, age facility and the oilseed press works jojoba and more. All of the Täby line of well. screw presses are distributed in the United States by Magic Mill International. See the Extraction by cold pressing Resources section for more information. Oil can be extracted mechanically with a Komet Vegetable Oil Expellers are manu- ram press, an expeller or even a wooden factured by IBG Monforts in Germany. The mortar and pestle, a traditional method company’s range of products covers small that originated in India. Presses range from hand-operated machines as well as indus- small, hand-driven models that an individ- trial machines. According to product litera- ual can build to power-driven commercial ture, Komet oil expellers feature a special presses. The ram press uses a piston inside cold pressing system with a single convey- a cage to crush the seed and force out the ing screw to squeeze the oils from various oil (Herz, 1997). oil-bearing seeds. Expellers have a rotating screw inside a The machines operate on a gentle mechan- horizontal cylinder that is capped at one ical press principle that does not involve end. The screw forces the seeds or nuts mixing and tearing the seeds. Virtually all through the cylinder with gradually increas- oil-bearing seeds, nuts and kernels can be ing pressure. pressed with standard equipment and with- The seed is heated by friction and electric out adjusting the screws or oil outlet holes. heaters or a combination of the two. Once the cap is removed, the oil escapes from the Figure 1. Sectional view of a Komet (single cylinder) oil expeller. cylinder through small holes or slots and the press cake, or meal, emerges from the end of the cylinder. Both the pressure and tempera- ture can be adjusted for dif- ferent kinds of feedstock. There are two distinct expel- ler press designs — a single cylinder press that expels the press cake out in pellet form and a traditional cage- style screw press that expels the meal out in large flakes. Oil expellers There are many manufac- turers of single-cylinder presses. Most presses are sold in European countries and designed primarily for rapeseed, or canola. For www.attra.ncat.org ATTRA Page 3 Some advantages and disadvantages of each Photo courtesy Ken DeBoer.