The following is a description of my RIMS brewery. Jeff Berton Mash/Lauter Tun: My combination mash/lauter tun is made from a sawed-off straight-sided stainless steel pony keg and has about a 7 gallon capacity. These straight-sided kegs have domed bottoms and a steel support "ring" around the bottom that acts as a "stand" for the keg. There is a dead space underneath the keg. I drilled a hole in the bottom domed portion of the keg and inserted an elbow pipe fitting with a half-inch diameter hose barb on one end. I fastened it to the keg dome with a nut and an O ring to prevent leakage. From the elbow, I run about two inches of hose to a half-inch diameter "tee" hose barb fitting in the dead space under the keg. From this "tee," I run more hose to two ball valves mounted to the side of the keg. These ball valves are inserted through holes drilled in the ring at the keg's bottom and are secured in place by tightening hose barb fittings onto them through the steel wall. One valve leads to the pump and in-line heater assembly (described below), while the other valve is opened later for the runoff during lautering. This valve is adjusted to yield the desired runoff rate. I wrap one-inch thick foam insulation around the tun and cover it with a lid to minimize heat transfer losses. The false bottom in the tun which supports the grain is simple and inexpensive to make. It consists of a 16-inch diameter pizza pan coated with a no-stick material and is perforated with hundreds of half-inch diameter holes. These perforated pizza pans allow pizza crust to brown better and are available from many kitchen supply stores. I laid some 18x18 mesh per inch stainless steel screen over the top of the pizza pan and threaded it on using fishing line. Since both the false bottom and the keg are circular, the pan fits snugly and neatly at the bottom of the domed keg with a relatively small ullage volume underneath. No grain can work its way into the ullage space. And unlike any slit-tube manifold drain arrangement, this false bottom arrangement has enough open area to allow good pumping rates through it. Even at my maximum pumping rate (5.5 gal/minute), there is no problem with wort passage through twelve or so pounds of grain and the false bottom. It is strong enough to support as much grain that can fit in the keg and it is easily removed for cleaning afterwards. Pump: I bought a March Manufacturing seal-less magnetic drive pump, model MDX-1/2, for $47. List price of this item is about $96, so shop for a good price. The impeller is magnetically driven. This type of drive design is nice for a brewery, since only food-safe materials come into contact with the wort. It uses 115V household electricity, can withstand a rated maximum temperature of 190F, accepts half-inch inside diameter hose, and pumps 5.5 gallons per minute at zero head. I run only a couple of inches of half-inch diameter tubing from the hose barb on the main ball valve of the mash tun directly to the pump inlet. I try to keep all tubing lengths to a minimum to minimize heat transfer losses. I built the pump speed controller designed by Rodney Morris shown in the special gadgets issue of Zymurgy using just a few dollar's worth of parts ordered from Digi-Key. The controller works fine. This pump pumps flawlessly with no cavitation or foaming anywhere. It is easily disassembled for cleaning, but I've found that a simple water rinse through the system after brewing works fine. In-line Heater: I bought a 1000-Watt electric immersion heater for about $10. The type of enclosure required for the heater is entirely dependent on the geometry of the heater. With my heater, I was able to enclose the element in one-inch diameter copper pipe. Copper "tee" fittings were used at each end to provide inlet and outlet ports. Copper end caps with holes drilled in them were used to seal the device and to allow the electric terminals to exit. All fittings were connected with lead-free solder except where the electric terminals exit the end caps. These terminals were secured with nuts and O rings to prevent leakage. Half-inch diameter hose barb fittings are connected to the inlet and exit ports. Hose runs from the exit port back into the mash tun. I branch the flow using three "tee" hose barb connectors to distribute the heated wort evenly throughout the tun. I make sure each exit into the tun is slightly submerged to avoid wort aeration and foaming. The heater output is controlled with a high-load dimmer switch. My dimmer switch is rated to 1000 Watts, which matches the output of my heater. These specialty dimmer switches can be found in hardware stores for about $20. Do not use a dimmer switch that is not rated to the capacity of your heater. I've found that a 1000-Watt heater is sufficient to increase the temperature of the wort at about one degree Fahrenheit every minute or two, depending on how well heat losses are minimized. When increasing the wort temperature between rests, I operate both the heater and pump at full capacity. Pumping rates must be kept high when the heater is at maximum power or wort scorching, and possibly even heater burnout, may occur. Once the desired rest temperature is reached, I turn the dimmer switch down to a point where a relatively small amount of heat addition matches the relatively small heat loss of the system. I thought I would need a thermostat to automate this process for me, but I've found this to be unnecessary. The part-power dimmer switch setting required to maintain a constant tun temperature is easy to find. After setting the switch properly, I can even walk away for fifteen minutes at a time without worrying about deviating too far from my desired rest temperature. This was good news, since I was intimidated by the electronic thermostat design in Rodney Morris' Zymurgy RIMS article. Hot Liquor Supply Tank: Another sawed-off straight-sided pony keg rests on a shelf above the RIMS mash/lauter tun. This tank contains a supply of constant-temperature, hot sparge water for use in lautering the grain. This tank is completely optional, since hot sparge water may be added manually from a stovetop pot to the RIMS mash/lauter tun; however, I decided it would be a valuable feature to add. A liquid level sight glass tube is mounted to the side of the keg to determine water volume. A 1500-Watt water heater element is also inserted through a hole drilled in the side of the keg. Since the sparge water never needs to be brought to a boil, this relatively modest water heater element is sufficient for this application. It is switched on and off by a bimetal adjustable thermostat encased in a cylindrical brass rod. It is also mounted through the steel keg wall and is secured with a nut and an O ring. It has a screw adjustment that I set at a sparge water temperature of 170F. Since this bimetal thermostat is accurate to only three degrees, it was not suitable for operating the main mash heater. However, since maintaining an extremely precise sparge water temperature is less crucial than maintaining a mash temperature, its use in the hot liquor tank is fine. The thermostat operates at 9 VDC and triggers the water heater element through a relay switch. A half-inch diameter hose barb fitting is mounted to the side of the tank. A short piece of tubing connects it to a water-dispensing solenoid valve. This solenoid valve, costing about $12 from a surplus supply, is triggered by an adjustable-level float switch mounted in the RIMS mash/lauter tun. During sparging, as the liquor level in the tun drops, the float switch electrically opens the solenoid valve and hot sparge water flows into the tun. When the water rises, the float switch electrically shuts off the solenoid valve. This automates the time-consuming sparging process. I fill the tank with the appropriate volume of sparge water and leave it alone. Temperature Monitoring: I built several temperature sensors that I distributed throughout the system. They consist of thermistors from Radio Shack (10 kohm at 77 F) encased in plastic tubing and cemented in place with food-safe silicone aquarium sealant. The sensor mass is small and response time is very fast. I placed these sensors in the mash/lauter tun, at the heater entrance and exit ports, and in the hot liquor supply tank. All the wires from these sensors are connected to a multiple selector switch. The desired sensor is selected and the resistance is read on a digital multimeter. I use a temperature vs resistance calibration chart on the wall to determine the temperature of the liquid at the sensor.