Oilseed Processing for Small-Scale Producers
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A program of the National Center for Appropriate Technology • 1-800-346-9140 • www.attra.ncat.org Oilseed Processing for Small-Scale Producers By Al Kurki, There are many varieties of seeds and nuts that Janet Bachmann, can produce oils for food, nutraceuticals, skincare and Holly Hill products, aromatherapies, fuels, and industrial NCAT Agriculture lubricants. This publication describes the basic pro- Specialists cesses involved in oil processing, including seed Published cleaning, extraction, clarifi cation, packaging, and February 2008 storage. Sources for more information and equip- ment are included in the References and Resources Updated by Al Kurki sections at the end of the publication. August 2018 ©NCAT IP134 Introduction Contents armers and small-business owners are ask- ing if it is possible and profi table to add Introduction ......................1 value to their seeds and nuts by extracting Getting Started ................1 F the oil. Th is is not an easy question to answer Basic Processing Steps.................................... 2 because there are so many variables, some of Oilseed By-products: which are noted in the following sections of this Meals and Hulls ............... 5 publication. Adding Value Adds Culinary oils include olive, sesame, saffl ower, sun- Costs .................................... 6 Saffl ower oil. Photo: NCAT Oils as Food and fl ower, grape seed, canola, apricot kernel, soy- Fuel: A (Bio) Oilman’s bean, corn, coconut, hazelnut, peanut, pumpkin, Story .................................... 7 and walnut oils. Some of these plant-derived oils Getting Started References ........................ 9 can be used to make soap, body and hair oils, Former culinary-oil businessman and consultant Further Resources .......... 9 detergents, and paints. Some can also be used to E. Peter Matthies, now living in Aachen, Germany, make industrial lubricants. Other oilseeds and suggests that you ask yourself the following ques- oil-producing plants are high-quality feedstocks tions before starting oil processing: for biodiesel and straight vegetable oil (SVO) fuel. • Why do I want to start oil processing? Oilseed processing expands the use of crops such • Will it be a hobby or a new economic enter- as sunfl owers and brings value to grape seeds, prise? which are usually waste products. • How big will the operation be? • How many diff erent products will be made, ATTRA (www.attra.ncat.org) Most oil processing in the United States is done is a program of the National including both oil and the press cake left on a large industrial scale. Small-scale oil extrac- Center for Appropriate Technology after the oil is pressed out of the raw seeds (NCAT). The program is funded tion is more commonplace in other parts of the through a cooperative agreement or nuts? world. As a result, many of the useful resource with the United States Department • Do I want to target mass markets or of Agriculture’s Rural Business- materials and much of the appropriate-scale Cooperative Service. Visit the specialty markets? machinery come from other countries. Th is pub- NCAT website (www.ncat.org) • What geographical area do I want to cover? for more information on lication describes the basic processes of oilseed our other sustainable agriculture and production, with extensive sources for additional Th ere are still more questions to consider, energy projects. information and equipment. including the following: www.attra.ncat.org Page 1 • Who else makes cooking oil? the moisture content of the seed should be • Where will I set up my business? close to 10%. Th e number varies consider- • What equipment will I need? ably for specifi c oilseeds. For example, rape- seed should be dried to a 7% moisture con- • Will I employ others? tent, camelina to about 6%, and sunfl ower • Do I have experience for this venture? to 8.5%. Saffl ower needs only to be dried If not, where do I get reliable training, to 11%, and soybean is safe for storage and technical assistance and advice? processing at 12% (Alam, 2007). • Where will I get the capital to start my oil Th ere are at least two methods of testing business? (Fellows and Axtell, 2012) seed moisture levels. Hand-held moisture Th e very fi rst question is important because it testers allow the user to simply place the aff ects the answers to all the other questions. It seed in the tester, turn it on, and select the even aff ects how you read this publication. If you type of seed to test. Th e tester provides an crush oilseeds for biodiesel or straight vegetable instant readout. Th ese testers cost as little oil fuel production, you need to pay special atten- as $200. Brand names include Dickey John tion to several specifi c processing steps. Portable Grain Moisture Tester MG3, the Graintec HE-50, and GE Sensing’s Protim- For culinary oils, there are several more process- eter Grainmaster. Related ATTRA ing steps and technologies to consider and pos- Publications sibly add to your plan. You may forego some of Here is a lower-tech, low-cost way of mois- www.attra.ncat.org the more complex, costly steps for exclusively ture testing: Weigh a sample of seed, and personal-use cooking oil or biofuel. then heat the sample in an oven at 300°F for Adding Value to one hour. Reweigh the sample. Th e weight Farm Products – lost in the oven is equal to the moisture An Overview Basic Processing Steps content of the original sample. Calculate Bringing Local Food Seed Cleaning the percentage by dividing the weight lost to local Institutions by the original weight and multiplying the Preparation of the raw material often includes result by 100. Tips for Selling to removing husks or seed coats from the seeds and Institutional Markets separating the seeds from the chaff . Th ere are many Even dry seed can quickly get damp by Tips for Selling to small- to intermediate-scale approaches to and being in contact with damp earth. Once the Restaurants technologies for eff ective seed cleaning. Approaches seed is dried and bagged, it must be stored carefully to keep it from absorbing moisture. Biodiesel: range from using various sizes of hardware cloth screens in tandem (Clothier, no date) to using a Do-It-Yourself • Warm. Warm seed will yield the most oil Production Basics compact fanning mill such as the Clipper Offi ce for the least eff ort. Th e optimum heat range Tester and a spiral separator for small farms (Anon., for oil extraction is from 100°F to 160°F. 2008). See the Further Resources section for Th ere are several ways to preheat the seed examples, types, and sources of equipment. in advance of extraction. For very small batches, heating the seed in an oven or Seed Preparation and double boiler works, as does concentrated Conditioning sunlight in a solar food dryer or some other For successful pressing, the seed must have the solar collector. For larger batches, a heating following characteristics: element in a hopper located between the seed-storage facility and the oilseed press • Clean. Fine dust in the seed may clog the works well. oil press hardware. Chaff left in the seed will absorb some of the oil and keep it from Extraction by Cold Pressing getting squeezed out of the expeller. Sand Oil can be extracted mechanically with a ram in the seed will wear out the press. Stones press, an expeller, or even a wooden mortar and damage the oil press screw or piston. pestle, a traditional method that originated in • Dry. Moist seed leads to low yields and clogs India. Presses range from small, hand-driven the screw or cage, a part of the press. Moist models that an individual can build to power- seed may also get moldy, as mold spores are driven commercial presses. Th e ram press uses a present in all crops. A rule of thumb is that piston inside a cage to crush the seed and force Page 2 Oilseed Processing for Small-Scale Producers out the oil (Herz, 1997). Expellers have a rotating screw inside a horizon- tal cylinder that is capped at one end. Th e screw forces the seeds or nuts through the cylinder with gradually increasing pressure. Th e seed is heated by friction and electric heat- ers or a combination of the two. Once the cap is removed, the oil escapes from the cylinder through small holes or slots and the press cake, or meal, emerges from the end of the cylinder. Both the pressure and temperature can be adjusted for diff erent kinds of feedstock. Th ere are two distinct expeller-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 in large fl akes. Figure 1. Sectional view of a Komet (single cylinder) oil expeller. Source: IBG Monforts Oil Expellers Th ere are many manufacturers of single-cylin- Th e machines operate on a gentle mechanical der presses. Most presses are sold in European press principle that does not involve mixing and countries and designed primarily for rapeseed, tearing the seeds. Virtually all oil-bearing seeds, or canola. For example, the Täby Press is a screw nuts, and kernels can be pressed with standard press manufactured in Sweden. It is similar to equipment and without adjusting the screws or the Komet Oil Expeller described below. Various oil outlet holes. models are available for cold-pressing rapeseed, linseed, fl axseed, sunfl ower seed, sesame seed, Some advantages and disadvantages of each type peanut, groundnut, mustard seed, poppy seed, of press follow: cotton seed, jojoba, and more. Single-cylinder Komet Vegetable Oil Expellers are manufactured Advantages: by IBG Monforts in Germany.