Send your  technical questions  about Mashmate here J-Parker@woh.rr.com

Send your RIMS brewing questions to the "Brew Master"  Bradley.Duncan@notes.udayton.edu

     In the Fall of 1991, soon after finishing graduate school in Electrical Engineering, I found myself with enough spare time on my hands to take on a new hobby. I had always wanted to learn to brew beer, so one afternoon I looked in the local yellow pages. To my amazement there was a "homebrew" shop in town. I had never heard of such a place, but after my first visit I returned home with about $130 worth of equipment and ingredients, a copy of "The New Complete Joy of Homebrewing" [1] and a big grin on my face.

     Later that evening, in true engineer fashion, I got out my roll of duct tape (just in case), ignored all the "So You Want to Homebrew" instructions the nice guy at the homebrew shop gave me, and jumped right into making my first "kit" beer. That night I learned the truth in the old cliché, "A watched pot never boils." I also learned that when you stop watching just long enough to go to the bathroom (one must always drink a fine beer or two while brewing, you know), a boil over will surely occur.  DISASTER!! The sight of my hissing cat standing on the kitchen counter, back arched, watching the sweet, thick, brown liquid roll out of the pot and onto the floor is not one I’ll soon forget.  What a mess!

     So I practiced, and practiced, and practiced. Pretty soon I was brewing exceptional beers and had converted some of my non-beer drinking friends into homebrew (and good microbrew) lovers. I even taught some of my friends to brew from extracts, always being amazed at how easy it was to make really good beer. All it takes is attention to sanitation, fresh ingredients and modest skill. Nevertheless, though my taste buds were happy, I remained somehow unsatisfied. I had found myself getting into studying the more technical side of brewing and brewing procedures, and decided to take my now two year old hobby to the next level. "There are no differential equations to be solved, so how hard can all-grain brewing be," I asked myself. Dumb question - kind of.

     Becoming an all-grain brewer is a bit like climbing a small mountain. The view from the top is outstanding, but it takes some effort to get there. The sense of accomplishment I now feel when a friend nods and smiles silently after tasting my latest all-grain brew is beyond compare. It has been well worth the effort to learn my craft. I feel almost like I’m an artist, my creation having come from a bucket of crushed grain, a few gallons of bottled water (my local water is lousy for brewing), some hops and several hundred million of my favorite one cell yeast friends.

     For me the most challenging, though not difficult by any means, aspect of learning all-grain brewing was learning to mash and sparge my grains effectively. It took me several tries to get it right. One and two step infusion mashing (I’ve never tried decoction mashing) is simple enough that everyone ought to try it. However, I have found that careful attention must to be paid to mashing and sparging procedures in order to ensure rapid and complete starch conversion, optimum extraction rates, and in order to later avoid having to boil unnecessarily large volumes of wort.

     I also want to be as lazy as possible on brewing day, because it’s usually Saturday. When my grains are mashing I watch TV, drink a homebrew, look for my duct tape, read my latest book on brewing, or just play with the cat. Mashing is boring, folks. It mostly involves lots of waiting while the little enzymes work their magic. But there is a catch. You can’t take a nap or go out for pizza. With simple infusion mashing, you really can’t leave your grains fully unattended. Every now and then you need to look in on them and make sure the temperature is stable and make any needed adjustments. Now, If you always start your saccharification rests at a high temperature, say 156 °F, no problem. As your mash cools, starch conversion will proceed nicely and will be finished in about an hour, even as the mash temperature begins to fall. However, if you prefer to mash at lower temperatures, say 152 °F, and attempt to produce a and more alcoholic and drier brew in the process, you will need to watch your mash temperature much more carefully. I’ve found that if the mash cools below 149 °F, mashing to full conversion can take forever. Frankly, I’d rather be doing something other than tending to my mash.

     If you are already an all-grain brewer, you have also probably noticed that sparging your grains after mashing often results in lots of fine particulate matter (i.e., the fine "flour" produced when you initially ground/crushed your grains) making it into the boiler, and maybe into your primary fermenter, if you don’t incorporate some sort of filtering process. This sludge is not harmful to your beer, but because it’s volume is hard to account for, you may find yourself actually loosing 2-3 pints of beer in additional sediment waste (on top of what you lose anyway due to yeast sedimentation and trub) when racking your beer after primary fermentation. Well, many homebrewers have figured out that if they collect the initial sparge runoff and pour it back on top of the grain bed, repeating the process a few times till the wort runs clear, they can eliminate this "flour" sediment problem altogether. Sounds easy enough (it is), and it does work quite well, so why not automate the process? Ah!, you can - read on.
 
     In my opinion, all grain brewing via simple infusion mashing is simple enough to be tried by all homebrewers. It doesn’t take a lot of equipment or skill (though practice is essential), yet it does have some practical difficulties which can be improved upon. If you are serious about fine tuning your all-grain brewing skills, or if you are new to all-grain brewing and are simply interested in avoiding the difficulties I mentioned above and want to "do it right the first time," a Recirculating Infusion Mash System (RIMS) is something you should really consider. The RIMS process was invented by Rodney Morris and was first reported in Zymurgy in 1988 [2]. His follow-on Zymurgy article in 1992 outlines in detail the steps involved in building and using a simple RIMS system for homebrewers [3]. For his pioneering work in the RIMS area, Rodney Morris is owed a great deal of praise and gratitude from the homebrewing community.

     In essence, a RIMS mashing system simply involves using a food grade liquid pump to continuously recirculate sweet wort, drawn from the bottom of a mash tun, first through a temperature controlled heating element, and then back to the to the top of the mash. The concept is quite simple, though constructing a RIMS homebrewery from scratch requires a fair amount of time. Most homebrewers will find that the most challenging and time consuming part of building their first RIMS system is building a properly functional control unit. The control unit is that portion of the RIMS hardware which provides for precise electronic control of the pump speed (i.e., recirculation rate) and wort temperature. Now, the second Morris article [3] provides the schematic for a simple control circuit, though after having built and tested this circuit for myself, speaking as an expert in the field (I have a Ph.D. in Electrical Engineering, and am an Electrical Engineering Professor), I regret to say that I have found this circuit to be quite crude and only marginally functional. I really don’t suggest you invest your time in constructing it.

     Alas, the punch line. After engaging in a full fledged RIMS controller design effort, Paragon Brewing has developed a first class control unit which can be directly incorporated into any RIMS system. We call it the Mashmate 1600, and it works absolutely flawlessly! Functionally, with my Mashmate 1600 I have been able to consistently achieve ~2 °F/min. heating rates (for typical 5 gallon batches) when using multi-step mashing procedures, with an estimated 0.05 °F holding temperature accuracy once a particular mash rest temperature has been established. The Mashmate 1600 provides for a simple set-and-forget mashing process that makes brewing day a lot more fun and a whole lot less taxing. In fact, I believe our control unit will set the standard for home built RIMS systems. If you are considering adding a RIMS system to your own homebrewery, make sure to contact us (if you haven’t already) about supplying the control unit. You will save yourself loads of construction and trouble shooting time and be assured of having a first class RIMS system that will work flawlessly the very first time.

     I now want to point out some of the general advantages of RIMS brewing, after which I will put to rest some myths I’ve heard regarding RIMS brewing procedures.

Advantage 1) Hands off mashing!  RIMS mashing procedures using the Mashmate 1600 are trivial, and once the desired mash rest temperature has been established your job is done till the rest is complete. You can indeed take a nap or go out for pizza if you wish. You no longer need to be a "pot watcher." I can easily get 30-32 gravity points/pound of grain with little or no effort other than turning the RIMS unit on. Actually, I believe RIMS mashing is so efficient that extraction efficiencies are limited only by the freshness of the grains you use and the quality of your grind.

Advantage 2) Crystal clear runoff!  Because of the continuous recirculation process, within minutes the wort will become absolutely crystal clear! You can read through it! This in turn means less sludge in your fermenter and less sediment waste at racking/bottling time.

Advantage 3) More rapid starch conversion!  As pointed out by Dave Miller in his classic homebrewing text The Complete Handbook of Home Brewing, occasionally stirring the mash assists enzyme activity, possibly reducing starch conversion times by as much as 25% [4]!! In RIMS brewing this "stirring" is automatically accomplished through the constant recirculation process.

Advantage 4) It is easy to mash large grain bills using RIMS!  Rodney Morris, for example, suggests that grain beds no deeper than 12" be used in a RIMS system [3]. In my 5 gallon Igloo® cooler/mash tun, my grain beds settle to depths of approximately 0.9"/lb. Should I want, I can easily mash slightly more than 13 lb. of grain in my little mash tun. That is a whopping grain bill, folks! There is really no need for enormous mash tuns in order to produce high gravity beers when using RIMS.

Advantage 5) Sparging is trivial!  When using RIMS, sparging is as simple as slowly adding a small amount of heated sparge water directly to the top of the mash, along with the rest of the recirculating wort. An equal amount is, of course, also drawn from the bottom of the mash tun and drained into the boiler. There is no need for fancy sparge water spraying apparatus.

Advantage 6) NO stuck runoffs!  Almost by definition, if the wort is properly recirculating, it is incapable of "sticking" during the sparging phase. This is because perfect grain/filter beds are rapidly established during the recirculation process.
 

Now to debunk some silly myths.

Myth 1) "RIMS systems work great at holding mash temperatures constant, but they don’t work well at raising mash temperatures between rests."  The reality is that using the original Morris circuit design, this was often indeed the case. This was one of the flaws, and I’ve heard similar comments regarding other commercially available small scale RIMS controllers. We have overcome this limitation in the Mashmate 1600, and can consistently increase mash temperatures at a rate of ~2 °F/min. for typical 5 gallon batches.

Myth 2) "I have heard or read [5] that RIMS mashing will make for thin or weakly flavored beers."  As I sit here with my latest India Pale Ale close at hand, I can say definitively that such claims are simply nonsense. Period! Seriously, this myth arises because of the thought that the low temperature mashing which takes place in heating the mash from, say, 122 °F to 152 °F will result in poorly flavored beers. The reality is that this jump using the Mashmate 1600 RIMS controller takes about 15 minutes. This is just not enough time to cause substantial starch conversion. In fact it takes about 75-90 minutes at 149 °F to result in full conversion. Plus, malt starch does not fully gelatinize until it reaches approximately 149 °F [4,6]. Until this happens, most of the malt starch is just not available for conversion, and no mashing really takes place.

Myth 3) "I’ll scorch my wort with RIMS techniques."  Nonsense. Even at slow recirculation rates, the wort passes by the heater element much too quickly to scorch or caramelize it. Plus, we recommend using low heat density heater elements, operated at half their rated voltage. For instance, a 5500 W, 220 V heater element run at 115 V will deliver only ~1500 W of heat to the recirculating wort. Your blow dryer likely puts out at least this much heat. When was the last time you burned yourself while drying your hair?

Myth 4) "RIMS systems are expensive and/or hard to build."  Well, you can go out and buy a $3500.oo turn key RIMS system from SABCO if you want to [5,7]. Their system is super nice, and I’m sure it is worth every penny for those whose must brew first class. But it is not for me. The simplest RIMS concept I’ve seen published is in reference [8] below, though no control unit details are provided, except to say that it has some glaring limitations which we have overcome in the Mashmate 1600. Using the Mashmate 1600, I’d imagine such a system would cost about $350.oo, complete on your first RIMS brewing day. I spent a bit more on my setup (about $475.oo) mostly because I’m a serious tinkerer. However, about $100 of my expense went into my mash tun, $40 of which was spent on the parts for a stainless steel mash screen. By comparison, I spent almost $230.oo on two stainless steel brewing kettles (one 10 gal. and one 6 gal.), with lids, when I first started all grain brewing. In the larger scheme of things, my RIMS setup was not out of line with other brewing expenses I’ve incurred, though it has made my brewing life much simpler and more enjoyable.  As for building a RIMS system based on the Mashmate 1600, all you need are modest copper soldering skills (to build the heater element housing), and some wiring ability (to properly connect in our control unit). If you are otherwise mechanically inclined, building a RIMS system is not difficult at all. The time spent on building the unit will, of course, be a direct function of how elaborate your final design is. A simple system will probably require a time investment of several evenings.  As for my own design, I built all but the final control circuit in my modest spare time over a period of about 3 months, but I really was not in a hurry at all.  For me, it made for a nice winter project when I found myself with nothing else to do.

Myth 5) "I need some sort of fancy PID temperature controller to build a RIMS system."  Nope, this is just not the case! PID stands for proportional-integral-derivative control. There is a whole field of study centered on control engineering [9], and I do not intend to give a full account of control theory here. However, it is fair to say that all properly controlled systems provide a "control signal" which is proportional to some parameter that is to be controlled – in our case the mash temperature. As such, all control circuits provide for some bit of proportional (P) control. In addition, control circuits which provide proportional AND "derivative" (PD) control seek to provide very rapid rise times, while also limiting or eliminating overshoot. In other words, if we wish to cause the mash temperature to rise from 132 °F to 152 °F, we prefer this to occur very rapidly, without overshooting our desired mash rest mark. The Mashmate 1600 was designed to provide just such PD control! On the other hand, PID controllers are designed to also control very rapidly varying phenomena – something that just does not occur in RIMS brewing. PID controllers are thus a bit of an overkill when it comes to controlling a RIMS brewery. Most commercially available PID controllers are designed as general purpose devices to suit a wide audience, whereas the Mashmate 1600 is designed specifically for RIMS usage. Plus, for the same price (often less) than a bottom of the line PID controller you will have access to the engineers at Paragon Brewing, Inc., to help you design your system! Whatta Bargain!

© Paragon Brewing, Inc.

Bradley D. Duncan, Ph.D. (©1997, revised 9/98)

References:
(Note: I've chosen references I hope most interested parties will be able to easily find.)

1) Charlie Papazian; The New Complete Joy of Homebrewing, Avon Books, New York, 1991.

2) George F. Ashley; "Profile: Rodney Morris," Zymurgy, Vol. 11, No. 4, pp. 22-25, Special Issue 1988.

3) Rodney Morris; "Recirculating Infusion Mash System Revisited," Zymurgy, Vol. 15, No. 4, pp. 49-54, Special Issue 1992.

4) Dave Miller; The Complete Handbook of Home Brewing, Garden Way Publishing, Pownal, VT, 1988.

5) Karl F. Lutzen and Mark Stevens; Brew Ware, Storey Communications, Inc., Schoolhouse Road, Pownal, VT, 1996. (Note: In my opinion, other that the comments regarding RIMS, this is otherwise a very nice book.)

6)  Dave Miller; Dave Miller’s Homebrewing Guide, Storey Communications, Inc., Schoolhouse Road, Pownal, VT, 1995.

7) "Homebrew Hardware Store," Zymurgy, Vol. 18, No. 4, p. 95, Special Issue, 1995.

8) Kerry S. Hauptli; "What about RIMS," Zymurgy, Vol. 18, No. 4, pp. 102-105, Special Issue, 1995.

9)  Benjamin C. Kuo; Automatic Control Systems, 4th ed., Prentice Hall, 1982.