RIMS Controversy
Although the latest issue of BrewingTechniques contains the usual plethora of excellent articles and ideas (kudos to Fal Allen for his excellent article - I can't wait for parts II-IV!), Dave Miller's column (at page 22) contains a world-class airball.
Contrary to his understanding, RIMS systems do clarify wort by recirculating it through a grain bed, and they do not pump the grain through the pump or heating element tube. Indeed, the false bottom and use of a well-developed filter bed are the real hallmarks and advantages of the RIMS system, as they promote quick and thorough conversion and a sparklingly clear wort.
Nor is it that constant agitation produces excessive tannin extraction in RIMS systems - excessive tannin extraction is due almost always to (1) excessive sparging, (2) not keeping the pH of the mash/sparge water below 5.7, or (3) hot-side aeration (which is not a problem with a properly designed and used RIMS system). I've never had any problems with huskiness or astringency on any of my batches (I use a modified prototype of the Brew Magic RIMS from Sabco [Toledo, Ohio]).
Louis K. Bonham
Houston, Texas
In the recent issue of BrewingTechniques, Dave Miller says, "As I understand it, the RIMS design does not clarify wort. It pumps the whole mash - grain and all - around and around through a tube."
This is completely wrong. A RIMS system uses a false bottom and pumps wort out from under the grain and deposits it back at the top of the grain bed, having heated it as it passes through the tube. One of the great advantages of a RIMS system is that it produces brilliantly clear wort, usually by about halfway through the saccharification rest.
Dave goes on to mention how the bad rap of excessive agitation in RIMS has been corrected by later systems. Thanks to him for dispelling this myth. Wort properly returned to the top of the grain bed through a manifold will not disturb the grain bed at all and causes no agitation of the grain at all throughout the entire mash. I cannot imagine any other system which could agitate the grain less.
Miller says, "My own view of the RIMS approach is that it seems to be a solution in search of a problem. The system's claimed advantage is precise temperature control . . . impressive . . . but not really necessary."
The advantage of a RIMS system is in its ease of use. I agree that 0.1 °F control is overkill, but still, it cannot hurt. The advantage is that I can do an upward step infusion mash with no more effort than turning the dial to the right temperature at the correct time. I never have to worry about scorching, raising temperature too quickly or too slowly, or overshooting a temperature for a particular conversion rest.
In fact, I liked the idea of precise temperature control with no hassle so much, I waited to convert from extract recipes to all-grain until I had my RIMS system working. It is a delight to use and allows me to "relax, and have a homebrew" while I am brewing, not run around like crazy between stove and ice water bath trying to control the temperature of a mash.
Dion Hollenbeck
San Diego, California
Just a note to correct Dave Miller's possible misunderstanding of RIMS designs and how they work. . . . He goes on to describe a "system" with ±0.1 °F precision temperature control. One might assume he's attempting to describe the very successful Brew Magic Brewing System, which uses the RIMS technology and is used both as a pilot system in commercial breweries and as a self-
contained small-batch brewhouse for the advanced home user.
With the Brew Magic, the whole mash, grain and all, does not get pumped around an around as he suggests. Only the wort is transported, very gently at that, through stainless tubing, at a regulated speed, past a microprocessor-controlled heating element and back to the top of a static mash filter bed. There is virtually no agitation whatsoever. Furthermore, hot-side aeration, caramelization, and frothing and foaming are negligible with this design. Yield efficiency is vastly improved with RIMS, and yet at the same time the variables inherent with the typical mash-mixing, air-pushing, hot-spot methods have all but been eliminated.
Five years of development and brewing on this system have passed without any apparent fermentation difficulties resulting from an almost crystal clear wort. For large batch sizes (beyond this system's capacity), perfect temperature control becomes progressively more difficult, and minor changes in product appearance and flavor become less obvious. However, with decreased volume pilot recipe testing and smaller batch homebrew production, subtle changes in methodology, temperature, and equipment handling become more serious threats to accurate, repeatable brews.
All in all, I feel that any technique, RIMS or otherwise, that improves consistency in brewing is a welcome "necessary" topic for major brewers, microbrewers, and home brewers alike.
Bob Sulier
Sabco Industries
Toledo, Ohio
As the person who wrote the question to Dave Miller regarding RIMS and lipids, I feel that I should address some inaccuracies in his reply. I think that he has a basic misunderstanding of the way in which RIMS works. In a RIMS system, only the wort is recirculated.
Essentially, RIMS is a modified lauter tun. The wort is collected from underneath a false bottom and is recirculated with a pump. En route, it passes by an in-line heating element that maintains the wort at a specified temperature. Although not all brewers may heat the first runnings during recirculation, it is thus far the same procedure about which Mr. Miller was writing in the March/April issue ("Wort Recirculation Questioned," BrewingTechniques 2 [2], 14-16 [1994]).
The differences between RIMS and a traditional vorlauf are that in RIMS the wort is recirculated during the actual mash, and the heating element and flow rate are used to maintain and adjust the temperature. As you can see, a well-designed RIMS system would call for minimal disturbance of the grain bed.
This technique is attractive for three reasons: accurate temperature control within ±0.1 °F, a higher extract yield, and a brilliantly clear wort. The latter is achieved because the wort is continuously clarified by the natural filter bed that the grains create.
What this all amounts to is a really long modified vorlauf of sorts. In his March/April article, Miller suggests that overzealous clarification might result in a lipid-poor wort which could contribute to fermentation problems. Given that assumption, it seems natural to me that a RIMS produced wort would, indeed, be deficient in lipids. Could you please re-address this question, and could you also explain how a RIMS system designed to minimize agitation of the grain could extract more tannins than a standard infusion mash? Does the mere action of the water flowing through the grain bed extract more tannins when taken to this extreme?
Samuel Lloyd Kinsey
New York, New York
Miller responds: I am sorry for muddying this issue with old information. Some years ago, I saw a prototype RIMS system and talked about it with Rodney Morris, its inventor. Subject to his correction, my recollection of that conversation was that the prototype did circulate the mash - not just the wort. If that is the case, then the newer versions now on the market represent a fairly major redesign. Such a redesign would make the system less prone to tannin extraction. As for overclarifying the wort, I find it difficult to believe that this is possible for most small-scale brewers, regardless of how long it is recirculated.
Dave Miller
St. Louis, Missouri
