Rodney Morris [75046,350] Recirculating Infusion Mashing System by Rodney Morris Introduction I developed this mashing system because I was dissatisfied with the ¨ traditional "pot on a stove" which I had used previously. This system was developed to have the following features: 1. Precise temperature control to within +/- 0.1! C so as to give repeatable ¨ mashing conditions from batch to batch. If a particular beer made with this¨ system is a bit too dry, I could precisely adjust the mash temperature a few¨ degrees on the next batch to change the ratio of fermentable to non­ fermentable carbohydrates. 2. Uniform temperature throughout the mash. The old system heated the malt¨ in the pot in a non-uniform manner, with precise temperature control¨ difficult. 3. Reduction of labor in mashing. There is no need to stir the pot during a¨ temperature boost. 4. Faster mashing than the old method. 5. Recirculation of the wort in the new method produces a brilliantly clear¨ liquid by the end of the final temperature rest. Formerly, it was necessary¨ to transfer the mash to a lauter vessel and then drain and recycle some of the¨ wort repeatedly until the wort ran clear. 6. Mashing and sparging is done in one vessel. Items Required Igloo Legend 36 quart cooler- If you mash 8 to 10 gallon batches, use a 48¨ quart cooler. A stainless steel open bottomed box which just fits in the cooler. I bought a¨ sheet of 20 guage stainless steel, nine inches wide and long enough to bend¨ into the box shape for $12 from a local sheet metal supplier. A flange 3/8"¨ wide was bent inwards on the bottom of the box to support an 18 mesh stainless¨ steel screen which was held in place by pop rivets. Two 5/16" diameter rods were run lengthwise of the box below the screen and¨ welded to the bottom of the box to hold it just above the cooler surface. The¨ bolting grade type 304 stainless steel screen has 70% open area, allowing a¨ very fast recirculation of the wort. If you use any other type of mash¨ support, be certain it allows rapid recirculation. The screening is available¨ from : McMaster-Carr (main office) P. O. Box 4355 Chicago Il 60680-4355 Orders: 312-833-0300 Los Angeles, CA office sales 213-692-5911 Dayton, NJ office sales 201-329-3200 Catalog # 9230T72, $4.42 per square foot The screening comes in 3 or 4 foot wide rolls and is sold in linear feet. I¨ bought enough to make several mash boxes. This company prefers purchase¨ orders. Ask for their 1000 page catalog of industrial products, which has¨ many items useful for microbrewery construction. A small magnetic drive pump with a heat resistant pump housing was used to¨ recirculate the wort. Check surplus dealers in your city for such pumps. The¨ selection criteria are: 1. Magnetic drive, no shaft to leak wort into the motor. 2. Pump housing connections for 1/2" diameter hose. 3. Pump capacity of four to eight gallons per minute at a one foot head. 4. Universal type motor capable of being speed controlled by a triac motor¨ controller. All pumps I have examined can be speed controlled. 5. Motor power of 1/50 to 1/20 horse power, with 1500 to 3000 RPM. 6. Shut off pressure of pumping at 6 to 20 feet of head. 7.Heat resistant pump head. Companies which make suitable pumps include March Manufacturing Co., Milton¨ Roy, and Little Giant. I recommend those made by March if possible. The original recirculating pump was bought from: Edmund Scientific Co. 101 E. Gloucester Pike Barrington, NJ 08007-1380 Orders: 609-573-6250 The surplus pump, which cost $24, is no longer available. After searching for some time, I found that a similar low-cost surplus pump¨ was available from: H&R Corporation 401 E. Erie Ave. Philadelphia, PA 19134 Orders: 214-425-8870 Unfortunately, this pump has also been sold out. They do get in additional¨ surplus pumps from time to time, so you might request a catalog from them¨ which has pumps listed in it. I have finally located two companies which routinely carry such pumps, but not¨ at surplus prices. Cole Palmer Instrument Co. 7425 North Oak Park Ave. Chicago, Il 60648 Orders 800-323-4340 They have the biggest variety of pumps anywhere at full retail price. They¨ also sell service kits for the magnetic drive pumps. A March MDX pump, Cat.¨ No. N-07004-10 sells for $104.00. If you mash 8-10 gallon batches in a 48 quart cooler, use the higher capacity¨ MDX-3 pump, Cat. No. N-07004-30, price $111.00. Cole Palmer accepts credit¨ card phone orders. W. W. Grainger, Inc. 5959 W. Howard St. Chicago, Il 60648 800-323-0620 They sell pumps and many industrial items at wholesale prices. They have over¨ 225 branches nationwide. Call them for the nearest branch to you. Also ask¨ for their 1600 page catalog, which has many items of use to microbreweries. ¨ They sell the March MDX pump, Cat. No. 1P676 for $60.87, and the MDX-3 pump,¨ Cat. No. 1P677 for $66.82. The mash heating element, R5 in the circuit diagram, is a nickel alloy low¨ density 240 volt, 4500 watt heating element for electric water heaters. It is¨ run at 120 volts, giving 1100 watts of heat. Use only this type of heater,¨ with a 15" long element, with the loop folded back most of its length to have¨ a low heat density. Tin plated copper heating elements are not recommended¨ because of their high heat density which can scorch the wort on the heating¨ element. I purchased the heating element form a local building¨ supply/hardware store for $11.78. Use the screw-in type. If you mash 8-10¨ gallon batches of beer, use a 5500 watt heater with a March MDX-3 pump and a¨ 48 quart cooler. Use a 1-1/2" diameter by 15-1/2" long copper plumbing pipe to hold the heater. ¨ The ends of the pipe are closed with copper pipe caps. One cap has a 1" hole¨ to admit the heating element. A 1" copper threaded coupling is mounted on this end to accept the screw-in heating element. At one end, a copper 1/2" T is¨ attached to receive the wort from the pump. The other end has a 1/2" elbow¨ attached at the top to carry the heated wort back to the top of the grain in¨ the cooler. All of the copper parts cost me a total of $12. Some plumber's¨ suppliers quoted me much more than the one from which I finally bought the¨ copper items. See figures 3 and 4 for construction details of the heater¨ tube. Do not use a larger diameter tube, since it would result in the wort¨ flowing more slowly past the heater element and being over heated. Figure 1 is a circuit diagram of the temperature controller. At points A and¨ B you may connect either of the two power indicator circuits shown at the top. ¨ The meter circuit will show the average power being used to heat the mash. ¨ H&R corporation sells surplus meters for about $5. If you use this meter¨ power circuit, the scale must be recalibrated to show the average power¨ accurately. The motor speed controller circuit shown in figure 2 may be¨ constructed using the components shown or a similar controller may be¨ purchased from H&R Corporation for $4. Do not use a light dimmer since the¨ inductive load may cause it to fail. You can convert a light dimmer to a¨ motor speed controller by connecting a snubber consisting of R15 and C7 across¨ the triac. Use only a low power CMOS type 555 timer in the circuit, since the current available from the CA3059 is insufficient to power a conventional 555¨ timer. The TLC 555 CMOS timer is available from Radio Shack. The 120 volt¨ neon indicator is also available from Radio Shack. Most of the components are available from: Digi-Key Corporation 701 Brooks Ave South P. O. Box 677 Thief River Falls, MN 56701-0677 800-344-4539 GFCI is a 15 ampere ground fault circuit interruptor wall outlet which I¨ obtained from a local hardware store for $8. Do not pay more than $20 for this¨ item. R3 may be a single turn potentiometer (Radio Shack) or a 10-turn precision¨ potentiometer and counter knob from a surplus dealer ($5 each). The 10-turn¨ potentiometer allows one to precisely set the desired temperature, but is¨ expensive unless purchased from a surplus dealer. R4 is the thermistor which¨ allows the CA 3059 to control the temperature of the wort. Use a small size¨ (0.1" diameter) bead type thermistor available from Digi-Key. Solder the¨ leads of the thermistor to two small wires. Coat the thermistor and bare¨ leads with a thin layer of epoxy cement. When the epoxy has hardened, insert¨ the thermistor into a short piece of thin wall brass tubing which is slightly¨ larger in diameter than the thermistor bead. The brass tubing is filled with¨ epoxy and allowed to harden. Use only brass tubing which is slightly larger¨ than the thermistor bead so that a rapid response to temperature changes in¨ the wort is possible. Make certain that the wire leads of the thermistor are¨ not shorted to the brass tubing. A convenient source of small size brass¨ tubing is from ball point pens. The thermistor is inserted through a small¨ hole in a rubber stopper at the inlet to the heater. An accurate digital¨ temperature display is available from Radio Shack, Cat. No. 63-841 for $13. ¨ Remove the circuit board from the case and unsolder the tiny thermistor bead¨ which is located underneath the slots in the front panel of the unit. Mount¨ this thermistor in another piece of brass tubing as was done with the other¨ thermistor. Mount this thermistor in another hole in the rubber stopper. Run¨ the wire leads back to the themometer board and solder the ends to the¨ location from which you removed the thermistor. This thermometer will display¨ Celsius or Fahrenheit. It will also show the time with a push of a button. ¨ My unit has an error of of 0.3! C. There is no temperature calibration¨ adjustment in this unit. The maximum temperature displayed is 69.9! C. A¨ larger digital thermometer with a remote probe included is available from¨ Edmund Scientific for $20. This unit reads to 199.9! (Fahrenheit only) and¨ has a temperature calibration potentiometer on the circuit board. Parts List All resistors are 1/4 watt, 10% unless indicated otherwise. R1 8.2 K, 2 watt film type R2 5.6 K R3 50 K linear potentiometer, single or 10 turn R4 100 K NTC thermistor, Digi-Key Cat. No. KC009N-ND, $2.04 R5 4500 watt, 240 volt nickel alloy (Incoloy) low heat density hot water heater element R6 130 K R7 100 ohm R8 47 K R9 10 M ohm R10 1.8 K R11 510 K, adjust for full scale on meter at maximum heating R12 2.2 K, 1/2 watt R13 100 K linear potentiometer R14 15 K R15 1 K, 1/2 watt C1 220 uF, 16 volt electrolytic C2 22 uF, 16 volt low leakage electrolytic or tantalum type C3 .01 uF, 50 volt ceramic C4 10 pF, 50 volt ceramic C5 0.1 uf, 200 volt mylar C6 0.1 uf, 100 volt mylar C7 0.1 uf, 250 volt mylar C8 0.1 uf, 250 volt mylar C9 2200 uf, 6 volt electrolytic D1 1 amp, 600 volt rectifier D2 Diac trigger for triac, or use a triac with a built in diac (quadrac) S1 15 amp SPST switch T1 15 amp, 400 volt triac with an isolated tab, Digi-Key Cat. No. Q4015L5, $2.25 T2 4 amp, 400 volt triac or quadrac, Digi-Key Cat. No. Q4004LT, $1.75 M1 100 uA DC meter MOT pump motor L1 100 uH choke (200 turns of 20 ga. wire wound on 1- 1/2" x 1/2" ferrite rod) Neon 120 volt panel mount neon indicator with built-in resistor GFCI 15 amp Ground Fault Circuit Interruptor Outlet CA 3059 Temperature controller, Digi-Key Cat. No. CA3059, $1.53 TLC 555 CMOS type 555 timer, Radio Shack Cat. No. 276-1723, $1.19 Mount the T1 triac on a 2" x 4" finned aluminum heat sink with thermal¨ compound between the triac and the heat sink, since it dissipates considerable¨ heat. Use an isolated tab type of triac so that the heat sink does not become¨ electrically live. The CA 3059 temperature controller uses zero voltage¨ switching to eliminate radio frequency interference. It operates directly of¨ of the 120 volt AC line, with no transformer power supply needed. The¨ temperature controller circuit uses proportional control to hold the wort¨ temperature within +/- 0.1! C, actually better than is necessary. The¨ controller anticipates the set point temperature when you boost it after a¨ mash rest, and automatically starts to reduce the heating power at 1.5! C¨ before the set point, preventing over shooting the desired wort temperature. ¨ At the set point, the average power needed to maintain temperature is about 60¨ watts. The wort should be recirculated at least 2.5 gallons per minute during¨ maximum heating in the temperature boost periods. The temperature¨ differential between the input and output of the heater should be 2! C. or¨ less with maximum power. Recirculation may be slowed during the rest periods. ¨ A sheet of 1/8" thick styrene plastic with 250 1/8" holes drilled in it is cut¨ to just fit the box and is laid on top of the mash. This prevents the stream¨ of wort from the heater from stirring up the mash. Figure 6 shows the connector made from copper tubing to replace the plastic¨ spigot which comes with the cooler. Safety Considerations Use this RIMS unit only on three wire grounded circuits. The unit must have a¨ ground wire attached to the heater tube and the case of the pump motor. The¨ ground will protect against shorts in the equipment. Use a GFCI type outlet,¨ since it will trip at about 5 milliamperes, unlike a conventional circuit¨ breaker. If a GFCI is not used, touching a 120 volt wire in the RIMS unit may¨ allow enough current to flow through your body to ground to kill you without¨ tripping a conventional circuit breaker or fuse. Assemble the copper tubes with only lead free solder. KMart sells small¨ spools of lead free 96% tin/4%silver or 95%tin/5% antimony solder. Tips For a Better Beer Now that you can have precise temperature control for mashing, here are some¨ suggestions for improving your beers. The ratio of water to grain in your¨ mash will affect the mash enzymes. Measure the water and weigh the grain so¨ as to produce the style of beer you like. Check and adjust the pH of the¨ mash, as the pH level will affect the enzymatic reactions. I recommend the¨ plastic "colorpHast" strips sold in better brewing supply stores. Use Cat.¨ No. 9582, pH range of 4.0 to 7.0. The indicator dye does not wash out of the¨ test strips. With weakly buffered solutions such as wort, immerse the test¨ strip for one minute before reading. You can also buy boxes of 100 test¨ strips from scientific supply houses for $8. I do not recommend the pen type¨ pH meters which sell for about $80. They have no temperature compensation and¨ have considerable drift, making them no more accurate than pH test strips. A¨ decent pH meter with stability and temperature compensation costs about $200. The salts in your mash and sparge water will also affect the type of beer you¨ make. Adjust the sparge water to the same range as wort (around pH 5-5.5)¨ with phosphoric or lactic acid to reduce the amount of tannins leached from¨ the barley husks during runoff. Two row rather than six row barley for all¨ barley malt beers is preferred, since the high proportion of husks in the six¨ row variety produces excessive tannins in the wort. Do not grind the grain too finely in a hand mill. Excess flour slows the¨ recirculation rate too much, resulting in scorching of the wort on the heater. ¨ I use a roller mill with 8" rollers to give a medium crush. I monitor the¨ mash development with a hand-held refractometer to determine when to cease and¨ start sparging. The refractometer is faster and more convenient than a¨ hydrometer. Unfortunately, refractometers are expensive, with a price around¨ $175. A refractometer is unsuitable for determining the gravity of a¨ fermented beer, due to the dramatic effect the alcohol has on the refractive¨ index. I can use this effect to measure a fermented beer with a¨ refractometer and hydrometer to determine the residual gravity, the original¨ gravity, the alcohol content and the final gravity of a beer. Do not exceed¨ 75! C with the sparge water, since very hot water may warp the plastic of the¨ cooler and gelatinize remaining starch which could then cloud the wort runoff. ¨ A decoction mash has little problem with hot (80! C) sparging, since portions¨ of the mash are boiled and little starch remains at the end of mashing. I use¨ a 1 kilowatt stainless steel heater unit which hangs on the rim of my sparge¨ water pot and has a thermostatic probe to maintain the sparge water at 72! to¨ 75! C. I bought this nice heater from H&R Corporation for $9.95. Leave the hot break trub and cold break behind when you fill the fermenter. ¨ Aerate (rouse) the cold wort so the yeast fermentation will get a fast start.¨ Use a clean, vigorous yeast starter and do not ferment at too high a¨ temperature. Projects Underway I am now developing a boil over detector which clips on the side of the wort¨ boiling pot and sounds an alarm when the foam rises at the beginning of the¨ boil. This battery powered detector costs under $5 and should prevent¨ boilovers from unwatched brew pots. I am also developing a 2750 watt¨ immersion heater for my brew pot that has adjustable heating power from 0 to¨ 100%. This heater is expected to cost under $30. With my electric rates, it¨ will cost 10 cents an hour to operate. Good luck in your brewing! Additional information on the RIMS system 1. The circuit diagram for the system is accurate. Various homebrewers have¨ constructed the device and found it to work. Check your circuit board¨ carefully for wiring errors before turning it on and doing a smoke test. 2. Use a ground fault circuit interruptor (GFCI) type of outlet for safety,¨ since an electrical hazard will result if you spill wort onto the electronic¨ components, etc. A GFCI outlet sells for $7.88 on sale at an area hardware¨ store, so safety is not expensive. 3. Cheap recirculating pumps are not readily available. Do not substitute a¨ pump with a slow flow rate for the suggested types, even if they are cheap¨ (for example, a pump used in evaporative coolers for homes). Check industrial¨ surplus stores for good, inexpensive pumps. I have found another surplus¨ company that sells a pump, when modified, will work. C&H Sales Co. 2176 E. Colorado Blvd. Pasadena, CA 91107 Phone 800-325-9465 Stock #PC8402 $39.95 This magnetic drive pump has a brass, heat-resistant head which pumps at 2.3¨ GPM, a little slow. You can use an autotransformer to increase the flow rate¨ sufficiently for use with the RIMS system. Buy a small 120 to 12 volt center tapped transformer rated at 2 amperes on the low voltage side. Connect the 12¨ volt windings in series with the 120 volt windings. Wire the transformer with¨ the line voltage connected to the 120 volt terminals, and connect the pump to¨ the series connected windings through a switch to select 120 volts, 126 volts,¨ or 132 volts as needed to control the speed of the pump motor. Do not use the¨ electronic speed controller with this setup. 4. Add about 1.3 quarts of water per pound of grain to the cooler and heat it¨ to about 6 degrees Celsius above the desired strike point. When you have¨ reached the desired temperature, turn off the heater, then add the grain while¨ pumping. Continue to pump for about 10 minutes, whereupon the grain will pack¨ down and the flow rate will decrease. Stir up the grain bed with a large¨ spoon, continue pumping for about 2 minutes, then turn the heater back on. I¨ do not need to stir up the grain bed more than twice during a mashing session¨ to keep a high flow rate through the grain bed. Mash out about 10-20 minutes¨ after the starch particles have digested and the recirculating liquid is¨ clear. 5. If the barley was ground too fine,the result will be a "set mash", which¨ is a mash in which the lauter run-off is slow or stopped. Crush the grain, do¨ not grind too finely. 6. If a large, strong suction pump is used without a box to hold the grain,¨ it can cause the grain bed to be compacted, reducing the flow rate¨ excessively. Also,if the pump is too far below the grain bed,it may result in¨ a strong hydrostatic head suction which compacts the grain bed and reduces the¨ flow of wort through the grain. The inlet of my pump is two inches above the¨ bottom of the screen. Also, I designed the RIMS unit so the box has a small¨ gap between the box and the walls of the cooler. The maximum hydrostatic head¨ is limited by the depth of the grain bed, never more than 9 inches. The wort¨ flows through the grain without suction into the bottom of the cooler to a¨ depth of about 1-2 inches, where it is drawn into the pump. 7. If a box is not used to hold the grain in the insulated cooler, you can¨ limit the hydrostatic head to the depth of the grain bed by vertically¨ securing a piece of 1-1/2 inch diameter by one foot long piece of PVC sink¨ tailpiece to the false bottom screen with wire to exclude grain inside the¨ tube. If the pump runs too fast, air will be drawn into the pump, but the¨ grain bed should not be compacted. 8. Use sufficient water for mashing. Various technical homebrewing books by¨ Noonan, Miller, Dr. Fix, etc. recommend a ratio of 1.25 to 1.5 quarts of water¨ per pound of grain as typical for mashes. The RIMS unit works well with about¨ 1.25 to 1.33 quarts of water per pound of grain. Miller considers 1.33 quarts¨ per pound of grain in his step infusions to be a "stiff" mash. 9. Do not have the grain bed over one foot deep. Commercial brewers may have¨ deeper beds during the lauter period, but they continually stir the top of the¨ mash beds during the lauter operation to keep the liquid flowing fast enough. 10. I have some extra CA3059 I. C.s for those who need them (until they run¨ out).