The core of an all grain homebrewing system is arguably how the mash process is completed. Here I describe and compare 7 popular homebrewery designs based on this property, all of which are capable of making great beer.
BIAB (Brew In A Bag)
Description: Strike water is heated in the lone brewing vessel, and a special bag or basket containing the grist steeps in this vessel for the duration of the mash at the target temperature. Temperature may be carefully adjusted or regulated with an electrical element (E-BIAB) or through direct firing of the brewing vessel. Sparging does not typically occur, but some set ups allow for it.
Rationale: Cost and simplicity are king.
Comments: The low cost and high simplicity makes this an excellent method for new brewers.
BIAC (Brew In A Conical)
Description: In comparison to BIAB, a modified conical fermenter is used for the lone brewing vessel. At the end of the brew, the beer can ferment in the same vessel it was mashed and boiled it.
Rationale: Combination of one of the most advanced and expensive pieces of equipment a brewer may have (a conical fermenter) with the simplest all grain brewing method (BIAB). Reduces clean up to a minimum.
Comments: Relatively new method, which may gain popularity in the coming years. A version of this has been commercialized by Brewha equipment.
Description: Strike water, heated by a hot liquor tank, and the grist are mixed in a mash lauter tun. The mash is stirred occasionally throughout the mashing process and may be heated directly in some cases to adjust the temperature.
Rationale: The strike water temperature is calculated such that when it mixes fully with the grist, the target mash temperature is obtained. This is typically a 3 vessel design, which requires minimal further equipment. Emphasis is placed on mash lauter tun insulation such that the temperature drop through the mashing process is minimized.
Comments: Often a cooler mash tun is utilized. A 3 tiered, “pump-less” brewery is possible with this system. Easily upgraded to any of the recirculating mash systems if the brewer sees fit. Fly sparging is possible with two pumps on a single tiered brew stand, one pump on a two tiered, or zero pumps on a three tiered.
HERMS (Heat Exchanged Recirculating Mash System)
Description: Mash is recirculated through a coil immersed in the hot liquor tank. The hot liquor tank temperature is used to regulate the mash temperature.
Rationale: The immersed coil gently heats the mash, maintaining enzyme activity. Mash enzymes denature at temperatures around 170F, so this method provides added safety in comparison to a mash design which applies heat directly to the mash. Recirculation yields high clarity wort.
Comments: Unless hot liquor tank water is in movement (recirculation or stirring), heat transfer efficiency will be poor. Many report difficulty in performing stepped mashes as a result. Highly popular brewery design.
C-HERMS (Counterflow – HERMS)
Description: In comparison to a standard HERMS design, both the mash and hot liquor tank water are recirculated through an external counterflow heat exchanger.
Rationale: This HERMS variant results in more efficient heat transfer than standard HERMS, resulting in quicker mash temperature control. The counterflow heat exchanger also serves as a wort chiller.
Comments: Two pumps are required in this design, but the counterflow heat exchanger replaces two HERMS brewery items – the HERMS coil and a wort chiller. The cost differences are not likely to be significant as a result. There are other benefits of having dual pumps such as fly sparging ability in a single tiered brewery and the ability to pump chilling water in breweries without running water. Plumbing is “more complex” than in a standard HERMS design. I personally use this design.
RIMS (Recirculating Infusion Mash System)
Description: Mash is recirculated through a specialized tube (“RIMS tube”) which contains an electrical heating element OR the mash is otherwise heated directly and recirculated.
Rationale: Does not utilize a heat exchanger for mash control, as the denaturing of enzymes should not be an issue with a sufficiently low density heat source, and constantly recirculating mash. The recirculation yields high clarity wort.
Comments: Only a single pump is required. Constant recirculation yields accurate temperature readings in a RIMS tube if it is utilized. An additional element or other heating source will be necessary in the hot liquor tank if traditional sparging methods are to be used. If used in conjunction with the no sparge method, only two vessels are necessary (boil kettle and mash lauter tun)
K-RIMS (Kettle – RIMS)
Description: In comparison to a standard RIMS design, the boil kettle and its heating source (electric element, induction kettle or gas fired) is utilized to heat the mash directly. The mash recirculates through the boil kettle in this process.
Rationale: In addition to the standard RIMS rationale, this design is an economical response to the overstated concerns of hot side aeration in homebrewing.
Comments: Unless a two tiered system is utilized (which it often is), two pumps are necessary. This is popularly used in conjunction with the “no sparge” method, requiring only two vessels (boil kettle and mash lauter tun) and one heating source. A version of this has been commercialized by Blichmann.