RIMS-HERMS, Which is Right for You?

RIMS-HERMS – Advanced Homebrew Systems

Building a RIMS-HERMS system requires many difficult decisions to be made before you can begin building your advanced brewing system. Many of these decisions come down to how much money you want to spend on your system, or whether you want to use some of your existing equipment, and whether or not you have any building skills, such as welding, electronics, wiring, etc.

The more you can do yourself, the less you will ultimately spend outsourcing your work. Before we get into the brewing sculpture, lets take a moment to discuss the basis of the two most popular systems, RIMS-HERMS.

RIMS, or Recirculating Infusion Mash System and HERMS or Heat Exchange Recirculating Mash System are the two most popular systems for homebrewers. There are many variations of the two so you must decide which you like most before you can design your system.
Follow along as I build my RIMS System.

RIMS: Recirculating Infusion Mash System

The Sabco Brew-Magic System

First the RIMS System: RIMS systems utilize a pump to recirculate the mash in the mash tun over some sort of direct heat. This direct heat may be an electric heating element which is suspended in either a copper or stainless tube.

Most people define a RIMS by this type of heat but I think that as long as the wort is removed from the mash tun while recirculating it over any heat source, then returning it to the top of the mash tun, then it is a RIMS system.

The other most popular method involves applying direct heat to the mash tun from a burner, either fueled by propane or natural gas. The pump keeps the wort recirculating fast enough so that there are no worries about scorching the wort.

In either configuration, the pump runs continuously during the mash and the heat, either the flame or heating element, is cycled on and off by a controller to maintain the set temperature in the mash. There are several places you can place the temperature sensor in this system, but I think the best is coming out of the MLT just past the valve.

HERMS: Heat Exchanged Recirculating Mash System

In a HERMS system, the wort is passed through a heat exchanger, usually in the form of an immersion chiller-type set-up inside the Hot Liquor Tank. The HLT is usually used since the water will be heated up and used for the sparge anyway, so why not utilize the energy for heating the mash.

The wort temperature is maintained in two ways. Either the wort is recirculated continuously and the heat source to the HLT is cycled on and off to maintain the set temperature of the mash, or the pump is cycled on and off to pump the wort through the heat exchanger when it needs to be heated up.

In this case, the water in the HLT is usually kept a few degrees above the set temperature of your mash to minimize the time it takes to heat the wort. A temperature sensor is usually placed in the flowline of the wort just past the heat exchanger in this case.

Benefits of a RIMS-HERMS
Advanced Brewing System

Here are the main benefits of using a RIMS-HERMS brewing system:

  1. When the wort is constantly recirculated through the grain bed, you end up with a much clearer wort than you would by simply performing a manual vorlauf. There isn’t much empirical evidence that this is truly better, but it just seems self-evident to most homebrewers that a clearer wort going into the boil kettle is better than a cloudy one.
  2. The mash temperature can be controlled much more precisely with a RIMS-HERMS than is possible when using a cooler for your Mash Tun.

    With better temperature control you are assured of getting the same wort you planned on when you designed the recipe you are brewing. With a cooler for your mash tun, there can be a three of four (or more) degree temperature drift and it is more difficult to control which enzymes are working on your beer.

    Your final beer may or may not end up as you had hoped when you designed the mash schedule. I’d much rather have precise temperature control over the mash so that if the beer ends up different than you had hoped, you can tweak the mash temp next time you brew and have confidence in your results.

  3. The idea of repeatability is one of the main reasons most people upgrade to a RIMS-HERMS system. At some point as you advance in the hobby of homebrewing, you will begin to design recipes or you will have quite a few that are favorites. Being able to tweak a recipe and get predictable results is a major reason for switching.

    Another is simply being able to attain consistent results, ie. being able to repeat last year’s Christmas beer that was such a big hit with the family. When used as a pilot system for a small brewery, repeatability is paramount.

     If the brewer can’t even repeat the recipe on a small scale, how can he know what he will end up with when he scales the recipe up to production volumes.

  4. Another benefit of a RIMS-HERMS system is that you can perform complex mash schedules. Single infusion mashes work well for most homebrewers, but there may be times when you want to perform a more complex mash schedule.

    The RIMS-HERMS systems allow you to easily step through your temperature stops with little effort on your part. No more boiling water infusions, or decoction mash additions to raise your mash temperatures to the next stop.

Possible Problems:

The main problems discussed on the forums regarding a RIMS-HERMS system deal with the possibility of scorching the wort when your pump goes out on a RIMS system (you never have to worry about scorching your wort in a HERMS system, since the wort never sees direct heat).

Another downside of these RIMS-HERMS systems is the cost. You can easily spend a thousand dollars on a simple system, and on up from there. Complexity may be a downside for beginning brewers. That’s why I recommend that you walk before you try to run. Get the basics down before you jump into these advanced systems, it will only make you a better brewer in the long-run.


And now it’s time for a discussion about RIMS-HERMS brewing sculptures.

A brewing sculpture is the structural component that not only holds the brewing vessels, but also houses all the various accessories used on the systems (such as pumps, burners, chillers, plumbing, etc.). Brewing on a sculpture allows you to manage all the processes easily and effortlessly.

There are basically three popular designs for RIMS-HERMS brewing sculptures. The Three Tier RIMS-HERMS, the Two Tier RIMS-HERMS, and the Single TierRIMS-HERMS system.

The design you choose will depend on how you want to brew, and just how complicated you want to get (or can afford). All three designs share some common traits. Burners are usually mounted to the frame with wind guards.

The fuel (propane or natural gas) is usually fed from a manifold to control valves for each burner. One popular way to plumb the burners
(click here to learn all about propane burners) is to use a dual furnace valve with intermittent pilot control which will turn off the main gas when the sensor senses that the flames have been blown out. It is a safety feature and not necessary, but still nice to have.

Plumbing for the wort and water can either be hard-plumed with valves controlling the flow to the various vessels, or you can use what is often referred to as a “quick disconnect” system.

This system was popularized by Lonnie McAllister and his Brutus 10 build. In this system, a pair of silicone hoses are moved from vessel to vessel, usually connected to a lid, to facilitate the transfer of fluid at one stage or another in the brewing process. It is a very simple and ingenious system and can save you a lot of money over the more complex piping and valves in a hard-plumbed system.

Most brewing sculptures are made of steel and are either welded or bolted together. Many of my clubmates collect old steel bed frames for their sculptures thereby saving a lot of money on raw materials at the onset.

There are many others, however, who construct their sculpture of wood. This can be fine if you can assure plenty of insulation from the heat and don’t mind the weight and bulk.

Let’s discuss each system in depth.

Three Tier Brewing System

First the Three Tier Rims-Herms Brewing Sculpture. A three-tier RIMS-HERMS system uses gravity to move the fluids from one vessel to another and eliminates the need for pumps. This can be a definite advantage when brewing where there is no electricity.

All three vessels are mounted at different heights so water and wort can be drained to each subsequent vessel as the brewing processes progresses.

The top vessel is usualy the HLT (Hot Liquor Tank) where water is heated for strike water and sparge water.  The middle vessel is the MLT (Mash/Lauter Tun) and the lowest vessel is the Boil Kettle (BK). Water is heated in the HLT and drained into the MLT for the mash and for sparging.

The wort is then drained into the Boil Kettle below during sparging and subsequently boiled. Some brewers have the boil kettle high enough to place a fermenter on the ground below the BK to facilitate draining the wort into its final vessel for fermentation.

There are two popular designs for three tier systems:

  • The Brew Tree type design where the vessels are all mounted off of a single straight pole at the same graduated heights needed for gravity draining
  • The three-level step design which can take quite a few different forms.

Some ways of getting the step design are by using a ladder or building the three steps into a
sculpture. Another is to use whatever natural or man-made devices you have available, such as countertops, tables, ice chests, etc.

The Brew-Tree style design uses a very small footprint and can be very
portable. It is inexpensive to build and should use very little if any plumbing. You should be able to employ either type of sparge (batch or fly) with this system.

The drawbacks for these types of systems are:

  • The HLT is above your head and the MLT is high enough that you must use a ladder when doughing in.
  • You will still need a pump and plumbing if you want to recirculate the wort.
  • Most of the time you will have to brew outside since the system is quite high.

Two Tier Brewing System

Two-Tier RIMS-HERMS Brewing Sculpture will have two vessels at the same height and one below or above. In this system, one of the transfers can be done by gravity, but the other will need a pump (or some manual means of transfer).

Sabco’s Brew-Magic system is one example of a two tier brewing system. It is popular because it is not as tall as a three-tier system.

You can have the MLT low so it does not require a ladder to dough-in or when stirring the mash, but, it still requires a pump to move either water for sparging or the wort to the BK (however you set it up).

Of note as well is MoreBeer.com’s Tippy Dump system which is a modified two-tier system with gravity feed and pump. Check out the picture for more details.

Single Tier Brewing System

Blichmann's 20 Gallon Batch Electric RIMS Brewing System
Blichmann’s 20 Gallon Batch Electric RIMS Brewing System

A Single Tier Brewing Sculpture is very popular for many reasons. In this system, all three vessels are at the same height and that height is usually designed to be low so the brewer can look into the vessels to monitor the action and a ladder is not required for doughing in or stirring.  It is much safer than the three tier set-up since there is not vessel above the brewer’s head.

The downsides are that it is usually more expensive to build since it will require a pump or two to work and it can be much larger than the brew-tree design.

With this system, a single pump will facilitate a batch sparge but you must have two pumps to fly sparge (one to move the sparge water to the MLT, and one to move the hot wort to the BK).

My RIMS System

I know this is a very simplified description of these systems. I’ll talk about automation later and give you a much more detailed idea of the thought process that goes into designing your RIMS or HERMS system. I chose to build a single tier, direct-fired RIMS system with two pumps.

The Mash temperature and HLT temperature will be controlled by two Love controllers. I will use three 10″ Hurricane burners on the all stainless steel frame which will be controlled by three dual control gas valves with intermittent pilot lights. I plan on hard plumbing everything with 1/2″ stainless steel tubing, using swagelok fittings and stainless pipe fittings when needed along with 8 stainless steel valves for controlling the flow of fluids.

For the MLT, I plan on installing a
Blichmann Engineering AutoSparge for the wort return during recirculation as well as the sparge water inlet during the fly sparge. For the Boil Kettle, I plan on installing a
Blichmann Engineering HopBlocker when draining the wort to the fermenter to keep the wort as clean as possible.

For the chiller, I will place an immersion chiller made with 40′ of 3/8″ copper tubing inside the BK and pump ice water from the HLT through the chiller while recirculating the hot wort through a whirlpool tube attached to the chiller. This should facilitate a quick cool down of the wort as well as channel most of the hot break and hop matter to the center of the BK allowing the Blichmann HopBlocker to pick-up as much clean clear wort as possible.   Keep an eye out on this site for updates as I build my system. 

References: Information for this article on RIMS-HERMS was adapted from the articles in Homebrewtalk’s BrewWiki written by Bobby M. entitled Brewing Sculptures and Rims-Herms.

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