Killer RIMS
Like many homebrewers, I came to a point with my partial-mash brewing that provided great beers but didn’t allow for the full creative control of the process that I wanted. Of course the next logical step is all-grain brewing. There are numerous methods to choose from for this style of brewing, but which was right for me?
I already owned a propane-fueled King Kooker and a converted 15.5-gallon stainless steel boil kettle to handle 12 gallons of wort. To avoid wasting money already spent, I wanted to incorporate these pieces with any new setup I bought.
My decision on what method to use was made for me at a home-brew club meeting in a fellow member’s basement.
In that basement was a one-half barrel RIM (recirculating infusion mash) system. Natural gas was piped into the burners. Two faucets from an overhead water pipe poured water directly into awaiting vessels. Two linked boil kettles accepted the lautered run-off for a true half-barrel output. Ventilation was provided by a restaurant-grade hood.
After I picked my jaw off of the floor and stopped drooling, I began gathering as much information about RIMS as I could. I talked to homebrewers and shop owners, and scoured books and magazines. I began drawing diagrams and sketches of different potential system setups. This helped me resolve questions about possible construction and operational problems before I built or bought anything else. I made a list of wants and needs. This RIM system had to be safe, strong, back saving, portable, storable, expandable, and versatile. Low cost wouldn’t hurt, either.
What I finally envisioned on paper was an open-frame steel table on which to place two kettles. Rails placed lower on the table would hold the burner and allow it to slide from under one kettle to another. A pump would first recirculate the mash liquid and then be used to transfer sparge water from the boil kettle to the mash/lauter tun. After collection, the pump would transfer the wort back to the boil kettle.
Now that the system is built, I must admit that I have achieved my goals. This system is very safe by virtue of its incredible sturdiness and strength. An engineering friend calculated that the table can hold 800 pounds in the center without flexing. He refused to be quoted because he fears somebody will make one, max the load with something hot and heavy, and get hurt in the process. He doesn’t want a lawsuit, and neither do I. So don’t park your car on it. In reality, two very full 15.5-gallon kettles would weigh a maximum of 400 pounds combined. With an even weight distribution across the entire table and its low center of gravity, a tipover would be very hard to initiate (at the dimensions of my table and with similar steel).
The strength of the table actually comes from the construction of the upper corners and the bolts. In each corner three rails meet to create six joining faces. Three bolts are used per corner, yet each rail receives two bolts at each corner. This interlocking makes for an extremely rigid structure. The bolts used in my table are anti-shear bolts, the same type used in suspensions and undercarriages of large vehicles. Technically, they are termed ASTM A325 Slip Critical Bolts. It may be overkill, but I’d rather be safe than sorry.
Using a pump to transfer liquid eliminates the height requirement found in many gravity-feed systems. When handling 10 to 15 gallons of liquid at a time, this is a back saver. The chances of a nasty liquid burn are greatly reduced, increasing the safety factor. Also, the minimal height allows the operating system to tuck under spaces a gravity feed can’t, which was a major construction concern at my South Philadelphia row home.
The table can be taken apart for transport or storage in several different ways. Removing the end rails and loosening the remaining bolts allows the two separated sides to scissor to a convenient size. Complete disassembly gives me a bundle of metal 36 inches long and 6 inches high, weighing 70 pounds. For speed and ease the entire assembled table can actually fit into the back of a standard station wagon.
The table was built with the potential to expand to a larger system, if needed. The table’s height was determined by the relationship between my kettle’s plumbing and the height of my fermentation bucket. I wanted gravity feed for the cool wort transfer to my buckets, so the low point of the interior plumbing needed to be higher than the bucket’s top-off point. If I ever get a taller primary fermentation vessel, perhaps a demi-john, all I need to do is increase the height of my table legs. The width of my table was determined by the burners, so if they change, so can the table. It is very important to stress that structural integrity must always be kept in mind, so any changes in dimension must be carefully thought out before the hacksaw begins its work.
The versatility of this RIM system is tremendous. Since the mash tun is heated along with the strike water, accurate resting temperatures after doughing in can be calculated. The mash tun capacity is huge. I used the parti-gyle method to make a barleywine and a Scotch ale from the same grain bill. There were 29 pounds of crushed grain and 10 gallons of water in the mash tun with room to spare. The mash didn’t stick.
Temperature step infusions are handled with ease. There is a liquid volume of three cups under my mash tun’s false bottom. With a low flame and the burner’s baffle plate swung into place to help spread the heat, grain scorching is eliminated during recirculation. Since a small volume of hot wort is briefly exposed to a cooler environment during recirculation, slight downward drifts of resting temperatures may occur. These drifts are eliminated with periodic applications of flame.
I like to get a lot of beer out of a brewing session. Occasionally, I will make 10 gallons of all-grain and five gallons of partial mash during the same brew day. The day can be surprisingly short if it is structured well. I start by using my boil kettle to make the partial-mash batch. While this is cooking, I prepare the mash tun for the grain batch. By the time I dough in, I am cooling the first batch. During recirculation, the cooled wort from the boil kettle is put into a fermenter. The boil kettle is cleaned, filled with sparge water, and heated. Starch conversion with RIM-ing is fast. Lauter, boil, and chill as normal and 15 gallons are done in a day. Pitch the grain batch with two different yeast strains, and three separate beers have been made. Of course 10 gallons of extract could be made, but I like the shorter heating and cooling times that a five-gallon batch provides.
This system will last a very long time for what I need. The pump is the only thing that can malfunction, and that is covered by warranty. Besides, this system can work in the manual mode if necessary. It is fabulous for ales and with experimentation could be used as a decoction system for lagers.
A system like this can be integrated with existing pieces as mine was, or it could be designed from scratch. Sketching details, talking to fellow brewers, sourcing materials, and reading everything I could get my hands on helped me custom fit this practical and efficient RIM system to what I wanted, needed, and could afford.
The Table
When I was done diagramming my complete setup, I wrote out a shopping list: metal for the brewing table, a pump for recirculation, a 15.5-gallon converted stainless steel mash/lauter tun.
My local homebrew shop provided me with the kettle, pump, and directions to the best steel distributor in the region. My table required close to 30 feet of 2-inch by 2-inch by 3/8-inch angle steel, which they cut in lengths to size for me on a mammoth industrial pinch cutter for a nominal fee. The price for the nuts, bolts, steel, and cuts was less than $35.
There are three important measurements to obtain before metal is cut for the table: the diameter of the kettles, the height of the burners, and the height of the collection or fermentation buckets. I allowed for a small amount of extra space around my kettles for extra stability.
Parts:
The following list of parts represents the pieces cut to size to fit my components; your sizes may vary. Remember, unlike lumber, the listed size of metal is accurate. This means that a 2-inch by 2-inch by 3/8-inch angle is 2 inches wide, 2 inches high on the outside of the angle, and 3/8-inch thick throughout. I suggest that you get your metal cut at the point of purchase. This steel is tough, heavy material, and having it cut there will make things much easier. All rails are 2-inch by 2-inch by 3/8-inch angle steel.
• Two long kettle support rails, 36 inches long
• Four short kettle support rails,
173/4 inches long
• Two burner support rails, 36 inches long
• Four table leg rails, 18 inches long
• Two side rails, 223/4 inches long
• 16 bolts, washers, and nuts, 11/2 inch by 1/4 inch
• One or two pieces scrap two-by-four lumber
Tools:
• Drill with 5/16-inch, high-speed steel bit
• Oil for drill bit lubrication
• Hammer
• Center punch
• Two to four C-clamps
• Paper towels
• Permanent marker
• Measuring tape
Putting It Together
For clarity I will use the terms left, right, front, and back as if you are looking at the table from the same point at all times. I built my table on the ground, but a decent size work bench will do.
Study the photographs accompanying this article. The stability and strength of the table come from the interlocking construction of the corners. It is of great importance that this design be replicated. Of equal importance is the quality of bolt used. Use strong, high-grade anti-shear bolts with this project because its structural integrity relies on them. They are not expensive and are easy to find.
Begin with the front left corner. Place a side rail on the ground, positioned from front to back. The interior opening of the angle should be facing down and to the left. A piece of two-by-four can be used to hold the rail in the proper position. Measure two inches in from the front end of the side rail and place a mark on the top. Place a long kettle support rail from left to right on top of the side rail, the left end of the kettle rail equal with the upper left edge of the side rail at the mark. The interior opening of the angle of the kettle support rail should be facing up and back. Clamp these two rails together.
Take a leg rail and hold it with the opening of the angle facing out and to the right. Place the leg in front of the kettle rail and to the immediate right of the side rail. The top of the leg should be flush with the top of the kettle rail, and the front edge of the leg should be flush with the front end of the side rail. Clamp the leg to either other rail. Loosen the clamps slightly and adjust the rails so everything is square, then retighten. The corner should look like what is shown in the diagram on page 37. There should be an empty space the size of a two-inch cube at the upper left front corner.
Three matching 2-inch-square areas along the rails have been created at the intersection of the side rail and kettle rail, side rail and leg rail, and the leg rail and kettle rail. The holes will be drilled here. From one side only, find and mark the center of each area with the center punch. Be sure to pick which side will be easiest for you to drill from. Using ample oil for lubrication, drill one hole. It will be a slow process. Clean out the hole and wipe away metal debris. Place a bolt and tighten down the nut. Move on to the second and third locations, repeating the process. When finished you should have a solid, uneven-length tripod. The remaining three upper corners are completed in the same fashion, in mirror image.
The installation of the burner rail is an easier process. Decide on the clearance for your burner(s) under your kettle rail, remembering the kettles will be approximately two inches higher than the bottom of the kettle rail when the table is complete. Combine your clearance, burner height, and three-eighths of an inch for rail thickness. Use this measurement and mark the four table legs from the bottom of the kettle rail. Holding the burner rail in the same alignment as the kettle rail, place the bottom of the rail against the new marks and clamp. I suggest that you clamp both rails at the same time and try to place your burner. You want to be sure it fits before you drill. Mine was a very tight fit, which takes a bit of twisting to get in place with the table in one piece. If the table is partially assembled, burner installation is easier. You decide what you want. Make sure the top of the burner is below the bottom of the kettle rails.
Find and mark the center of the overlapped areas of the leg rail and burner support rail and drill.
Insert the bolts, tighten, and the major construction is finished.
At this point I suggest marking the rails in some permanent manner to make sure all the pieces are matched from this time on. If your drill holes were not perfectly centered, marking it will make reassembly easier by tenfold.
Take the table apart to the component pieces and give the metal a good washing to remove remnant oil and metal fragments. Coat the table pieces with a high-temperature paint of your color choice. I may recoat mine with Chevy Orange or stripe it with yellow and black caution lines.
After the paint has dried, put the table back together. Install the burner(s). Take one of the four unpainted short kettle support rails and hold it like an inverted V. Place this rail from front to back across the long kettle support rail at the left end of the table. The second short kettle support rail is placed in a similar fashion across the long kettle support rails at the right end of the table. The remaining two short kettle support rails are placed side by side across the long kettle support rails at the center of the table. There should be a four- or five-inch gap between the center short kettle support rails. These support rails were cut one-quarter of an inch shorter than the interior distance between the upper rail sides. This gives the supports more than adequate room for heat expansion.
Place your kettles on the short support rails, two rails per kettle. Adjust the short supports side to side to make a nice, stable platform on which the kettles will rest. The short rails should be spaced far enough apart so they won’t block the burner’s flame but not far enough away to allow a wobble in the kettle. The table is now complete.
The Pump
The pump I use for my RIM system is a March MDX-MT3. It is a magnetic drive pump that eliminates the conventional shaft seals found in most pumps. This means there is no leaking or fluid contact with metal surfaces, a plus for brewing. The pump can handle temperatures up to 200° F. This pump runs at a constant 3,000 RPM. It will pump water at eight gallons per minute (GPM) at a 1-foot head (height) and pump six GPM at a 6-foot head (height). There is plenty of power for this system.
The pump housing contains the impeller magnet assembly. The impeller spins on a ceramic spindle and pushes the fluid. The housing has one inlet and one outlet port for liquid to enter and exit.
These ports are threaded with 1/2-inch MPT threads, the same as used on a common garden hose. A trip to the home store netted the pieces I needed to reduce the ports to the 3/8-inch barbed plumbing common on my system. Because the pump runs at one speed, I placed an adjustable ball valve between the port and 3/8-inch barb on the outflow side.
The impeller should not run for more than 30 seconds dry, or it will bind to the spindle. Placing the valve on the outflow greatly reduces the chance of the housing running dry. The impeller can spin forever with fluid, so a closed ball valve with a running pump is no concern.
Making a base for the pump is not necessary, but it makes things a lot easier to handle when all of your brew equipment is out. The possibilities of shape, size, and location are completely up to you. I created a large L-shaped wooden structure. The pump was bolted to the base of the L. An on/off switch and safety features were attached to the vertical part of the L. For carrying ease, a hinged handle was placed on the back of the vertical L piece.
Starting and stopping the pump safely is the next issue to be addressed. The pump as purchased has only an electrical cord. It is up to the buyer what type of on/off switch and plug to use. The on/off switch I purchased has a pilot light to indicate the switch’s status. This is very handy. The plug I purchased is a good quality, heavy-duty piece.
Because the pump is to be used in a very wet environment, it is of great importance to include a ground fault circuit interrupter (GFCI). The GFCI, when installed correctly, senses voltage fluctuations like those seen when the bad guy dumps a plugged-in radio into an occupied bath tub, and it stops the current in a micro-second. This device can be a life saver, and it must be used.
If you are familiar and competent with electrical wiring, this hook-up should take no more than 30 minutes to complete. If you have even the slightest doubt about what you are doing with the electrical hook-up, I advise in the strongest terms possible to let somebody who does know what he is doing complete it. Pay him with a homebrew and a promise of more to come.
The operation of the pump in a RIM system is easy, but there are some items to remember. First, think ahead about where you want your fluid to go. Second, make sure the plumbing valves are closed when they are supposed to be closed. Third, gravity still works in a RIM system. That is both a good thing and a bad thing.
I use a total of three clear, 3/8-inch hoses when I brew. Hoses are attached to the plumbing with circular plastic clamps. I leave my pump in one position during the brew day, so each hose is a different length to correspond to a specific job it has in the system.
I begin my pump use with recirculation. The plumbing of my mash tun is connected by hose to the inlet port of the pump. A hose placed on the outlet pump runs up the side of the mash tun and lays coiled on top of the grain bed. I open the mash tun’s valve completely. Remember, do not restrict fluid flow into the pump. The outlet valve is then opened. Fluid will flow by gravity into the pump housing and out into the outflow hose. The pump is started, and recirculation begins. Use the outlet ball valve to adjust the flow of fluid into the grain bed. A hole can be bored into the grain bed by a high flow. This will reduce the efficiency of extraction, and that is the opposite of our intentions.
When conversion is complete, the pump is stopped and valves are closed. A new hose is placed on the sparge water kettle’s plumbing and then placed onto the inlet fitting of the pump. If the outflow valve is not closed, gravity will begin to siphon wort from the grain bed and deposit it onto the ground. Remember valve position! (Can you tell this happened to me?) The still-connected mash tun’s hose is placed into a wort collection bucket. The hose on the outlet side of the pump is attached to a sparge arm. All valves are opened, the pump started, and sparging begins. I use a flying mash, so I am always adjusting the pump’s flow to maintain an even saturation of the grain bed.
Once I have finished collection, the pump is turned off and all valves are closed. Any remaining sparge water is dumped into another bucket to clean equipment. My collection buckets have valves similar to bottling buckets. I place the bucket on a cinder block to have the fluid level higher than the pump head. I place a hose onto the collection bucket’s valve and connect it to the inlet valve of the pump. The hose is removed from the sparge arm and put into the boil kettle. All valves are opened, the pump started, and the wort transfers to the boil kettle for cooking.
Using the System
Finally, I was ready for my RIM system’s test run. This system is perfect for a single-step infusion, so I chose a pale ale to start. For this first batch I also decided to make a five-gallon batch to minimize any losses from the ever lurking Mr. Murphy. I planned a thin, wet mash of 1.5 quarts of water per pound of grain to help avoid a stuck mash.
Using a calculation to determine final resting temperature from strike temperature, I doughed in to the preheated mash tun. I hit the resting temperature within a degree. Manual recirculation set the grain bed after about one gallon. I connected a short hose to the mash tun’s plumbing and then to the inlet of the pump. I then connected a long hose to the outlet of the pump.
This hose snakes up and into the mash tun and rests on top of the grain bed. Opening the ball valve all the way on the mash tun and halfway on the pump, I turned on the power. Recirculation started with a rush of fluid boring a hole into the grain bed. I turned the pump’s ball valve back to achieve a more gentle flow. By the time the sparge water had reached temperature over a medium flame, the mash had starch conversion.
With the pump off and valves closed, I switched hoses. The short hose was placed to collect sparge water from the boil kettle’s plumbing, and the long hose was attached to a rotating sparge arm. Lautering was begun. Wort collection into a bottling bucket was easy since 45 minutes of recirculation had established a strong grain bed. Setting my bottling bucket onto a cinder block above the level of the pump head and switching hoses again, I transferred the wort to the now empty boil kettle. I began the boil with Mr. Murphy never showing up.
A year and eight batches has gone by, and I have hardly changed anything. The only improvements I have made were to add a second burner — no more sliding back and forth — and an additional bucket with a spigot to aid in large-volume wort collection.
