Small-Scale Oilseed Presses: an Evaluation of Six Commercially-Available Designs Chris Callahan1 and Hannah Harwood1 Heather Darby,1 Doug Schaufler,2 Ryan Elias2

Small-Scale Oilseed Presses: An Evaluation of Six Commercially-Available Designs Chris Callahan1 and Hannah Harwood1 Heather Darby,1 Doug Schaufler,2 Ryan Elias2

1 University of Vermont Extension, Burlington, Vermont

2 Pennsylvania State University, State College, Pennsylvania As part of a project on adding value nents (Figure 1). In “cold-pressing,” to farm operations with food-grade the seed goes into a central hopper of oils, the University of Vermont Ex- the press and is moved through one tension and Pennsylvania State Ex- or more screws, crushed against a tension teamed up to evaluate the nozzle and screens to extract oil design and operation of several small without heating the seed above a -scale oilseed presses. While there is temperature of 120°F. Oil and meal a great deal of interest in the produc- are separated. tion of oilseeds, many questions arise Presses vary in the number and about post-harvesting processing, breadth of adjustment each needs and many of these concerns revolve and is capable of. Some presses have around the efficiency, affordability, multiple nozzles, with differing di- and best practices of an oilseed Figure 2. Nozzles vary on different ameter holes for differing crops press, which is the heart of the oilseed press designs. (Figure 2). Some have collars that oilseed production system. are heated to a given temperature structions and customer service can Most commercially-available oilseed before operation. vary greatly. Many of the presses are presses have the same basic compo- Unfortunately, manufacturers’ in- made overseas, and it can be difficult to get guidance in installing, wiring, and operating a press, either due to language barriers or geographical distance. In addition, the operational guidelines for different crops can vary. Here in the Northeast, where many growers are producing more than one type of oilseed crop, there is an interest in the type of press that can handle different crops, and in establishing some guidelines for commonly-used oilseed crops. This report aims to guide both estab- lished oilseed processors in best management practices and collabora- tive experiences and also aid new or prospective processors in decision- Figure 1. Standard components of a small-scale oilseed press. making processes.

Methods duct objective evaluations of six dif- RULES OF THUMB ferent press designs (Figure 3). The Researchers visited oilseed pro- team evaluated the AgOil M70, Kel- - Start with clean seed. cessing facilities across the Northeast ler KEK P0020, KernKraft 40, Komet - Test and take note of moisture to interview press operators and con- CA59G3, Oil Prince, and Täby 70 (this will vary by crop and press). presses (Table 1). - Take note of seed temperature. At each press location, the same seed - Make small adjustments as you was used to conduct a controlled ex- go, rather than big changes. periment. Sunflower seed (var: ‘Syngenta 3480’) was harvested in basic setup but was at a faster speed 2012 in Alburgh, VT; canola seed (adjusted Hz/RPM) to demonstrate a (var: ‘5535 CL’) was harvested in higher pressing capacity. Finally, 2012 in Brandon, VT; and soybeans each machine was run at a lower (var: ‘Boyd’) were harvested in 2012 speed (adjusted Hz/RPM) with the in Charlotte, VT. intent of yielding more oil. Quantita- Each press evaluation began with tive and anecdotal data from each normal operation, using the individu- method (and sometimes trials at ad- al operator’s preferred tuning of the ditional speeds) were noted. Each Figure 3. Researchers and farmers machine. The second method of op- method was repeated for each of the work together on press evaluations. eration for each press used the same three oilseed crops when possible.

Table 1. Specifications for six presses evaluated during the course of this study.

         

(lbs seed/24 hrs) (lbsseed/24 capacity Estimated year + cost purchase Approximate source Power load Rated speed Adjustable head / barrel Heated screws Multiple nozzle Adjustable screw and head between gap Adjustable set of Ease

available diameter

PRESS

$8,500 1.5 kW / AgOil M70 700 240v X X X Simple (2012) 2.0 HP

$8,300 2.2 kW / Keller KEK P0020 1056 230v X X Simple (2010) 3.0 HP $15,000 3.0 kW / KernKraft 40 1200 220v X X X X X Finicky (2010) 4.0 HP $8,000 1.1 kW / Komet CA59G3 260 115v AC X X X Simple (2008) 1.5 HP Oil Prince $6,000 2.2 kW / 1800 220v X X X X X Finicky (KernKraft 20F) (2012) 3.0 HP $7,000 2.2 kW / Täby 70 1500 220-240v X X X X Moderate (2005) 3.0 HP

Press 1. AgOil M70 Roger Rainville of Borderview Re- MANUFACTURER search Farm in Alburgh, VT pur- CONTACT INFORMATION chased an AgOil in late 2012. The cold screw press is made in the [made in U.S.A.] United States, one of many deciding www.agoilpress.com factors for Rainville, who was interested in readily-available parts and service. AgOil Mondovi, WI The AgOil has a simple design, with Figure 5. The AgOil M70 comes (877) 645-7737 a single screw and an in-line Varia- with three different sized nozzles: [email protected] ble Frequency Drive (VFD) mount- 220, 250, and 280. ed on the gear box (Figure 4). With relatively few adjustments to be seed flow into the press, observing others to achieve the maximum effi- made, the press is simple to get run- cleanliness and any potential mal- ciency for a given crop or condition ning according to Rainville, and can functions. A “blast gate” stops seed (Figure 5). be used to easily switch between flow when necessary. As used at crops without stopping to adjust. Borderview, after the band heater AgOil indicates that oil extraction has brought the temperature to ap- efficiency on the M70 is 82-90% of The press itself takes up very little proximately 120°F, the heater is re- the oil content in the seed. Trial re- space, with dimensions of approxi- moved and the machine’s motor is sults from this study show an aver- mately 10”x10”x39”. A clear feed turned on. A central screw inside the age of 24.2% net oil extraction hopper allows processors to watch barrel forces seed against the crush across three crops (canola yielded plate and retainer. Meal is extruded 24.6% oil, soybean averaged 5.7% in the form of oil, and sunflower averaged 38.6% crude pellets, oil). and oil drips from the crush Rainville has been satisfied with the barrel’s holes. AgOil so far, though it has a lower capacity than his other presses. A variable Press capacity averaged 697 lbs in speed controller 24 hours over multiple crops and allows opera- speed settings. tors to adjust the speed of the The press came with very minimal machine and setup instructions, so initial installa- allow for the tion was cumbersome according to extraction of Rainville. However, customer ser- more oil. There vice since then has been mostly reli- are three differ- able with this American-made oil ent nozzles that press. The company also provides come standard “crush tests,” in which a sample of with the press; the grower’s particular crop can be Figure 4. AgOil 70 press at 40 RPM, pressing soybeans. they can be shipped to the facility for testing. swapped out for

Press 2. Keller KEK P0020

The German-designed Keller KEK P0020, which is approximately 51”x12”x27”, is simple, with very few adjustments (Figure 6). Only the screw speed and the distance or gap between the head and the collar leave room for fine-tuning, making the press streamlined and effective.

Operator Lloyd Byers in Liverpool, PA, purchased the press for $8300 in 2010, with freight included and an installation cost of about $600. Byers reports that the Keller is easy to set up for pressing, and requires very little supervision once running. When the press is running for long periods of time, he checks a few times a day to make sure seed flow Figure 6. The Keller press has a single barrel and drive. and press operation are optimal, but can generally leave it unattended begin. Byers generally operates the the day of the press evaluation, nei- with a large quantity of seed to press at approximately 32 RPMs, ther soybeans nor canola could be press. and uses the number of visible pressed through the mill. Byers has threads between the screw end and pressed canola with great success in Unlike many other small-scale press- the nozzle as a reference for setting the past, but difficulties with soy- es, the Keller requires no “pre- the gap. Oil is extracted through the beans remain a problem. Customer heating” with band heaters to start. crush barrel, and the meal produced service, however, has been prompt Operators simply turn on the motor, is in a “flake” form (Figure 7). Byers and thorough. load the hopper with seed, and looks for flakes about the size and shape of potato chips to indicate that DISTRIBUTOR the press is operating as it should. CONTACT INFORMATION The consistency and speed of the meal is the most reliable indicator of problems with press operation. Man- [made in Germany] ufacturers promise that the use of “hard-wearing” steel reduces costly www.keller-kek.de maintenance and repair issues.

Distributor in the U.S.: In this trial, the average mass oil Elwyn Beck fraction for sunflowers was 40.7%, Figure 7. This was the only press Sioux Falls, South Dakota and capacity averaged 130 lbs in 24 evaluated in this study that produces (605) 354-1323 hours. Byers has used the Keller meal in the form of flakes, rather mainly for sunflower seed, and on than pellets.

Press 3. KernKraft 40

The KernKraft 40 (KK40), owned and operated by Roger Rainville at Borderview Research Farm in Al- burgh, VT, is a workhorse design with high capacity and little supervision required (Figure 8). Rainville’s model was purchased in 2010 and has been used to press over 60 tons of seed since then. A large hopper built into the press allows for smooth flow of seed into the two screw chambers. There is a slide closure between the hopper and screw to stop seed flow if necessary.

DISTRIBUTOR CONTACT INFORMATION

Figure 8. KernKraft 40 at Borderview Research Farm in Alburgh, VT. [made in Germany] in the other before operation. When Eric Hamilton at Circle Energy has Distributor in the U.S.: the screw becomes scuffed, polishing been integral in the setup, mainte- it will help draw more seed through nance, and operation of Rainville’s Circle Energy the barrel and increase overall flow KK40. Hamilton has been easily ac- Dodgeville, Wisconsin (Figure 9). cessible by phone or email and has helped troubleshoot and work Eric Hamilton, (608) 574-7449 The KK40 has twin barrels, which through problems with the press, increases the capacity of the press [email protected] even traveling to Vermont to help set overall. In 2013 trials, average ca- it up initially. pacity for varying crops and settings Many adjustments are possible with was 1033 lbs in 24 hours. Average the KK40: operators can modify oil mass fraction was 24.8% over- screw speed, nozzle/die size, the dis- all (23.8% for canola, 8.2% for tance between the screw end and the soybeans, and 38.0% for sunflow- nozzle, and the heat of the barrel ers). (with removable band heaters). There are also two available screw types In research trials and based small (hard/deep groove or soft/shallow batches, the dual barrels and mul- groove). The soft seed screw comes tiple possible adjustments some- with the purchase of the press; the times led to frustration. Often, one hard seed screw (useful for soybean, barrel would become clogged and flax, and other crops) must be pur- backed up while the other would Figure 9. Scuffed screws (left) need to be chased separately. A small “key” is continue extracting oil and meal polished (right) to increase press efficacy. removed from one screw and placed effectively.

Press 4. Komet CA59G3

This has been determined through experience with the press on different crops. Another indicator of smooth operation is the temperature of the oil being extracted; when it gets too hot, it may be because a blockage inside the crush barrel is creating friction. Once the press is running well, there is little fine- tuning or supervision required. After the seed has been run through com- pletely, the nozzle is removed from the press and cleaned thoroughly.

Though Penn State University never received installation and operation manuals from the manufacturer, Figure 10. The Komet CA59G3 is small but reliable. email response from customer ser- The Komet CA59G3 is made by the 5 mm nozzle for both sunflower vice has been prompt and thorough. IBG Monforts in Germany. It is an and canola. Because the press is a The Komet press is used at Penn electrically-driven model that is European model, all units are metric, State University for small batches of small in size (approximately including bolts and threads. Opera- seed, processing approximately 500 26”x22”x23”) and capacity (Figure tors can adjust the speed of the lbs of seed per year. “This has been 10). The Komet is a typical screw- drive. a real reliable, real consistent ma- type press, with a screw bringing chine,” asserts Schaufler. The press seed through the shaft to press oil During pressing, Schaufler looks for has actually been used to demon- out of it. a reasonable output when pressing to strate oilseed processing at farm be sure the mill is operating well. shows and outreach events, being The Komet is pre-heated to approxi- sent to various locations with little mately 130°F with a removable band DISTRIBUTOR more than a one-page instruction heater prior to pressing (for approxi- CONTACT INFORMATION manual on its operation. mately 10 minutes). Operators can adjust the screw speed; agricultural [made in Germany] The advertised capacity of the mill is engineer Doug Schaufler at Penn www.oekotec.ibg-monforts.de/ 3-5 kg of seed per hour, which State University generally begins would equal up to 260 lbs of seed in pressing at approximately 55-60 Distributor in the U.S.: 24 hours. Though the Komet was RPMs. unable to be used for soybeans dur- Nebraska Screw Press ing these trials, the average oil mass While there is no adjustment in the Lyons, Nebraska fraction for canola was 34.4%, and gap between the tip of the nozzle sunflower seed averaged 45.1% oil. and the screw, there are multiple (402) 307-0280 The average capacity for these two nozzles, with varying diameters for crops, across speed setting, was 193 specific crops, though Schaufler uses [email protected] lbs in 24 hours.

Press 5. Oil Prince (KernKraft 20F) The Oil Prince, as it is sometimes of dripping oil indicates effective DISTRIBUTOR called, is another name for the Kern- operation. CONTACT INFORMATION Kraft 20F (Figure 11). This is a When the press slows down, Bou- smaller, single-screw KernKraft cher adjusts the sliding gate to mini- model with similar adjustability and mize seed flow until the machine [made in Germany] operation to the KK40 (page 5). works well again. Operators find that The Oil Prince has adjustable screw the press clogs less frequently when Distributor in the U.S.: speed, nozzle diameter, and two run at a lower speed. Clean seed go- available screw types (for hard seed ing into the hopper makes for more Circle Energy and soft seed). A sliding gate be- trouble-free pressing, and the built-in Dodgeville, Wisconsin tween the hopper and the screw al- magnet on the seed hopper prevents lows operators to control seed flow metal from entering the mill. Eric Hamilton, (608) 574-7449 at the throat of the press. Operators Average capacity of the press was [email protected] John Hutton and Meghan Boucher at calculated at 928 lbs per 24 hours. Coppal House Farm in Lee, NH heat Sunflower averaged 38.3% oil mass sometimes be a moving target. the collar with removable band heat- fraction during the trial, and canola ers and then add seed. For them, 2-3 This press, relatively new to its oper- averaged 26.6% across speed set- rows of holes in the crush barrel full ators, has a learning curve. During tings. On the day of the process of troubleshooting, the the press trial, oper- team also discovered a fracture in the ators could not press collar which may have been linked to soybeans effective- a prior issue with a ball bearing be- ly, despite an all- ing passed through the machine; this day attempt at data damage may have been preventing collection. The effective pressing of soybeans. problem could have While it runs extremely well and is been in the moisture reliable with canola and sunflower, level of the soy- other crops may take some adjust- beans; the Oil ment. Prince at Coppal House Farm has not yet been used to successfully press soy (Figure 12). Eric Hamilton at Circle Energy in WI, when called to troubleshoot this soybean problem, suggested adjustments and modifica- tions, but said that press operation can Figure 12. Close-up of collar head Figure 11. Oil Prince at Coppal House Farm in Lee, NH. and nozzle with too-hot soy meal.

Press 6. Täby 70 John Williamson runs State Line the plate, then back- Biofuels in North Bennington, VT ing off to leave a gap and relies mainly on a Täby model of approximately 2 70 oil press as the center of his oper- mm between the head ation (Figure 13). John has pressed and the screw. numerous crops (including sunflower, soybeans, canola, camelina, flax, In 2013 trials, the cranbe, safflower, mustard, and pen- average mass oil frac- nycress) with the Täby, which re- tion was 25.3% quires minimal adjustments and has (25.8% for canola, proven reliable over the last eight 7.5% for soy, and years. 38.3% for sunflower). The average capacity The Täby 70 was designed specifi- was 934 lbs per 24 cally for small-scale use, and to ex- hours. tract oil from a wide range of crops. A 2.2 kW motor drives the press, As with other press- Figure 13. Täby 70 oil press with custom-made oil pan. forcing seed through the crush barrel es, only clean seed at (or “press tube”) and nozzle. The the proper moisture should be Täby 70 is the language barrier. press has a thermostat and speed pressed, in order to extrude the max- Manufactured in Sweden, Täby control built into it (Figure 14), so imum amount of oil possible. The presses come with an instruction that the drive shaft rotates at variable Täby’s seed hopper has a built-in manual (installation instructions, speeds (maximum speed is 80 Hz or magnet to prevent any metal from safety warnings, and technical ad- 149 RPM). Operating instructions flowing into the press. A heater con- vice on troubleshooting and mainte- stress the importance of tightening trol on the gear housing stops the nance) in broken English and cus- the press collar all the way against press from running if the collar tem- tomer service can be delayed with peratures exceed 302°F. minimal domestic support.

Maintenance requirements are DISTRIBUTOR minimal with this machine. CONTACT INFORMATION Approximately every 10,000

operating hours, the gear oil should be changed. The spiral [made in Sweden] seed screw can become worn www.oilpress.com over time, and Täby suggests shipping the screw in for repair (re-hardening), rather than pur- Distributor in the U.S.: chasing a new one. Using only Magic Mill clean seed reduces and slows Upper Saddle River, NJ the wearing-out of multiple parts. (201) 785-8840 [email protected] Figure 14. Side-mounted control panel. One stumbling block with the

General Findings During the course of these evalua- pounds of seed in a 24-hour period Table 3. Capacity (lbs per 24 hr) based tions we assessed individual presses (Table 3). Not all crops were run at on press and crop, 2013 study data. and observed general trends in re- all screw speeds. Those selected gards to pressing capacity and net oil were based on operator insight and yield relative to speed, as well as whether or not seed could actually be quality characteristics of oil. pressed at the given speed.

As expected, the faster the press is Press Setup run, the more seed that is run through it. The press is, after all, a pump with It should be noted that these results the movement of material through it represent data from a single nozzle dictated by the speed of the screw and screw setup of each press for that pushes the material through. each specific crop (Table 2). However, the measured capacities vary notably by oilseed crop. Table 2. Nozzle and screw type setup by press, 2013 evaluations.

N/A – The Keller press has only one option for press nozzle setup. Failed test – The evaluation team was unable to successfully press soybeans on these presses during this evaluation. Press Capacity Oil Mass Fraction or Yield A common consideration among A less intuitive finding of these eval- oilseed press purchasers is the capac- uations was the relationship between ity of the press, or how many tons it oil mass fraction and press speed. Oil can press in a day. In our evaluations mass fraction is the measured pro- we explored operation of the presses portion of oil in the test sample com- at different speeds (measured as ac- pared to the meal once the seed is tual screw RPM) and measured the pressed. It is often simplified or used amount of seed pressed in a given as an indicator of oil yield. amount of time. These data are sum- marized with capacity listed as

Table 4. Oil mass fraction (%) based Press evaluations revealed a maxi- on press and crop, 2013 study data. mum of oil mass fraction in most cases when the press was run more slowly than the default speed (Table 4; see boldface figures). The conclu- sion is that if an operator is interested in extracting as much oil as possible from a given seed, a slower press speed may be preferable. This is especially true if the press is underuti- lized on an annual basis (i.e. over- sized for the current operation.)

Figure 15. Oil samples shipped to Penn Phosphorus Levels in Oil State University for quality testing. Phosphorus is used as an indicator of gum content in oils. Gums accelerate Fine-Tuning and Troubleshooting oxidation and therefore reduce shelf life due to rancidity. Gums can also A learning curve is to be expected, impede effective production of bio- especially when working with differ- diesel by disrupting the transesterifi- ent crops and conditions. With all cation process most often used to presses, there is a certain amount of make fuel from oil. In our press eval- troubleshooting and fine-tuning that uations we subsampled oil and tested each operator will undoubtedly go for equivalent phosphorus level us- through. ing AOCS Official Method 12-55 For example, when seed flow slows (Figure 15). down, as it will invariably do at times, identifying and resolving the Interestingly, phosphorus in oil is blockage is crucial to prevent caking minimized at lower speeds (Figure and overheating. Each operator in- 16). In some cases, it can be reduced volved in this project seemed to have by a factor of 3.7 by simply adjusting strategies for overcoming routine press speed. problems like this. One press manu-

Figure 16. Effect of pressing rate on phosphorus levels in oil by crop, 2013 data.

facturer suggests mounting a thermo- Table 5. General moisture recommendations and extraction rates by crop. stat and/or flow capacity controller to detect problems and automatically Ideal Pressing Average Extraction shut down the machine. Most agreed Moisture (%) Rate (%) that the press should be stopped, cleaned out, and started again in order Canola 6-9 25-30 to identify, and hopefully fix, the problem. Occasionally, turning up the Soybeans 8-12 8-12 speed of the motor can help clear a blockage. Sunflower 8-12 35-40

All operators mentioned the importance of taking time to learn the Additional resources: quirks (and strengths) of a particular press. Keeping detailed notes about Schaufler, D. 2013. Oilseed Fact Sheet: Oilseed Presses. Penn State Univ., the temperature, moisture, and cleanli- State College, PA. Available at http://www.uvm.edu/extension/cropsoil/ ness of seed going into the press, as wp-content/uploads/Oilseed-Presses.pdf well as press settings and calculated throughput, will help growers estab- Callahan, C., H. Harwood, L. Madden. 2014. Small-Scale Oilseed Presses. lish local operating procedures. It is University of Vermont Extension, Pennsylvania State Extension. our hope that this report gives pro- YouTube. http://youtu.be/4bfkb_FOn3w (accessed 27 Feb. 2014). spective oilseed processors an ad- vantage in getting started. A YouTube video complements this report and provides more information (see addi- For more information on oilseed production and processing, please visit tional resources at right). http://www.uvm.edu/extension/cropsoil/oilseeds

Acknowledgements

This research project was funded by Northeast SARE Grant 11-309 “Adding Value to Oilseed Crops by Producing Food Quality Oils.” UVM Extension and Penn State Extension would like to thank the following farmers for the willing participation in this project: Roger Rainville at Borderview Research Farm in Alburgh, VT; John Williamson at State Line Biofuels in North Bennington, VT; John Hutton and Meghan Boucher at Coppal House Farm in Lee, NH; and Lloyd Byers in Liverpool, PA. Without the time and shared experience of these press operators, this project would not have been possible.

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