How to Recirculate the Mash (And Why You Should)

In all-grain brewing, there are a lot more factors in the brewers control. Many of these factors can make a significant difference in the quality of the beer being made. One of these that often go unnoticed by the beginning all-grain brewer is recirculating the mash.

Recirculating the mash is a simple step that can really make a big difference in the clarity and quality of your brew. Making the time or investment to perform this step correctly will help you to set up a proper filter bed in your mash, which will remove unwanted solids and proteins from your beer. When done right, the reduction in haze-inducing proteins alone will make a huge difference in the appearance of your beer.

Here, we will discuss several methods of recirculating your mash, as well as the benefits you should expect from doing so. All but one of these methods requires the use of a pump.

The No-Pump Method

If you can’t afford to drop money on that mash pump right away, you can still recirculate your mash with this method. The pros of using this technique are that it is practically free to do and it incredibly easy to set up. The cons are that it is labor intensive and it can be very hard to maintain the mash temperature while you do it.

First, you’ll mash completely. With a cooler setup and no pump, recirculating during the mash will result in too much temperature loss to truly be effective, and may result in stuck sparges or very low conversion rates.

If you have room in your mash tun to add enough hot water to hit your mash out temperature, you should do so before recirculating.

Once you are ready, you will use a pitcher or two and slowly drain the wort from the bottom of your mash tun into a pitcher until it is nearly full. Then, without slowing the wort flow, swap out the pitchers and pour the first pitcher gently into the top of the mash tun, being very careful not to disturb the grain bed.

As you go, you will repeat this process until the wort is running very clear. Once it it very clear, you can then move your drain hose into your brewing kettle and let it drain. If you use continuous sparging, you can then begin allowing the sparge water to flow in through the top as you drain from the bottom. If you batch sparge, you should be performing this recirculation every time you add more hot water, as stirring will disrupt your grain bed and cause clarity or quality issues.

Using A Pump to Recirculate the Mash

Investing in a mash pump is a great way to improve this process. To recirculate the mash using a pump, you can hook the output of your mash tun to the input of the pump, and then feed the output of the pump into the top of the mash tun. It helps to utilize a sparge arm or similar tool for ensuring the wort coming back in the top does not disrupt the grain bed.

To adapt the previous “no-pump” method to the use of the pump, you’ll ditch the pitchers. Let the wort flow down into the pump and then turn the pump on. Most brewing pumps aren’t self-priming, so you’ll need to keep the pump below the liquid level and make sure the pump has wort in it before turning it on or you could burn your pump out.

To restrict the flow of the pump, you will need to add a ball valve to the outlet side of the pump. You will want to open the ball valve on your mash tun completely and use the pump’s ball valve to regulate the flow.

For most setups, I would recommend not running this during the actual mash, as you could reduce the temperature of the mash significantly, reducing your conversion rate. If you insulate the hoses and have a very short run, however, it could be conceivable that you could reduce the impact of this. Ideally, however, you would have a way to heat the wort as it recirculates. Which is where the next type of recirculation system comes in.

RIMS Systems

The ultimate step for recirculating the mash while retaining temperature is building a RIMS or HERMS system. A RIMS system, the short name for Recirculating Infusion Mash System, utilizes a heating element that comes into direct contact with the wort during the recirculation process. A HERMS system, also known as Heat Exchanged Recirculating Mash System, uses indirect heating through a heat exchanger to accomplish the same goal.

In an example RIMS system, for instance, you may have your mash tun drain into a kettle with a heating element in it. Based on the temperature in the mash tun, the heating element may turn on and off to heat the wort being circulated through the kettle.

A good example of this system is the BrewMagic by Sabco, which uses an in-line heating element to heat the wort as it passes through the tubing. An alternative is the Blichmann Breweasy system which utilizes a Two-Tier no sparge brewing system. Instead of having a third vessel holding sparge water, you would add the full volume of liquid at the beginning and then skip the sparging step. This method is a lot like brewing in a bag.

The BrewMagic system uses an in-line heating element in the recirculation tubing. When the mash tun’s temperature gets too low, the element fires and heats the recirculating wort, raising the temperature little by little until it is back where it needs to be.

Both of these systems are RIMS systems, and they are very effective at recirculating the mash while controlling the temperature in the mash tun. The advantage of these systems is that they are time saving and allow for constant recirculation during the entire mashing process, which makes a much clearer beer.

HERMS Systems

The close cousin to the RIMS system is the HERMS system, which relies on an indirect heating element to aid in the maintenance of the mash temperature during recirculation.

A great example of a HERMS system is The Electric Brewery. This DIY brewery system utilizes the hot liquor tank as a heat source and a stainless steel coil of tubing in the mash tun through which your mash will cycle. Since the body of liquid inside the hot liquor tank is held at a constant temperature, it is often just set at the mash temperature and the liquid is constantly cycled through it. Alternately, these mash systems can be set up to kick the pump on and off while the hot liquor tank is set at a higher temperature.

Whichever way it is implemented, the HERMS system can be a very effective way to recirculate the mash during the conversion process.

Takeaways

Recirculating the mash during the conversion process is the optimal way to save time while also greatly improving the clarity and quality of your beer. However, if you are unable to recirculate during the starch conversion process, doing so immediately afterwards will also greatly increase the quality of your beer, though it will take a bit longer.

Regardless, if you are an all-grain brewer and you are not recirculating your beer, you are not making the best beer you can make.

Cheers!

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