As an all-grain home brewer, I'm always looking for ways to make my brewing process and my beer better. One way to improve process it to reduce the length of a brew day. All grain brewing takes hours and can easily consume an entire weekend day. I'm not as obsessed with optimizing total brew time, though, as reducing the tedious and error-prone aspects of brewing that can lead to mistakes and delays. Among the most tedious of brewing activities is monitoring mash water temp as it heats, trying to avoid overshooting the target temperature. It's also the critical path activity at the beginning of a brew day. I recently built a simple solution to this problem that is both inexpensive and effective while requiring minimal equipment. Even if, like me, you are using a basic cooler-based mash tun and kettle setup, you already have most of the equipment you need. For about $100 (less if you already have some of the necessary equipment) you can wake up to hot strike water and be mashed in within minutes of starting your brew day.

Equipment Needed

Mash Tun : If you brew all-grain, you already have this. It works even better if you mash in an insulated cooler, such as an igloo cooler.

: If you brew all-grain, you already have this. It works even better if you mash in an insulated cooler, such as an igloo cooler. Temperature Controller with waterproof probe: I used this pre-wired controller by InkBird, the ITC-308. Since it's pre-wired, there's no need for a project box or additional wiring. This controller is dual-stage, so it can be used for fermentation temperature control as well. It's also significantly cheaper than many competitive options. The waterproof probe is the killer feature for this project as the probe can be submerged directly in the mash water.

I used this pre-wired controller by InkBird, the ITC-308. Since it's pre-wired, there's no need for a project box or additional wiring. This controller is dual-stage, so it can be used for fermentation temperature control as well. It's also significantly cheaper than many competitive options. The waterproof probe is the killer feature for this project as the probe can be submerged directly in the mash water. Bucket Heater : This 1000 W bucket heater comes prewired to plug in directly to the temperature controller heating stage and features important safety measures including a guard around the heating element to prevent burns and a thermal fail-safe to prevent fires.

: This 1000 W bucket heater comes prewired to plug in directly to the temperature controller heating stage and features important safety measures including a guard around the heating element to prevent burns and a thermal fail-safe to prevent fires. Submersible, High Temperature Pump: A pump is used to recirculate the water during heating. I used this small, inexpensive (~$20) pump placed directly in the mash tun. This ensures no temperature gradients develop and increases heating efficiency as the water is constantly flowing over the heating element. The submersible pump is both cheaper than typical brewing pumps and simpler to use. Just drop it in the water and turn it on. There's also no risk of air bubbles leading to pump burnout. This pump requires a 12 V, 1.1 A power supply. I used this cheap power supply (~$5) connected directly to the pump leads.

Setup and Use

Connect the bucket heater to the heating stage output of the temperature controller. It plugs directly into the ITC-308. 1 Place the bucket heater in your mash tun filled with the correct volume of strike water for your recipe. Submerge the recirculation pump in the water and connect it to a GFCI outlet. Ensure it is recirculating the water. The one I used above is more than adequate to maintain a constant whirlpool in several gallons of water. Connect the temperature controller to a GFCI outlet and set the desired mash temperature. Go to sleep. 2 Wake up to perfectly-heated strike water. Mash in!

Set up is simple:

I used this setup for my last brew day and mashed in within 15 minutes of waking up. If you adjust the water chemistry for your beer, you can even add salts the night before and the pump will ensure they dissolve fully. Previously, it would often be up to 45 minutes to set up equipment and heat water to strike temperatures with the occasional annoyance of overshooting strike temps. There's also no need to preheat the mash tun as it has already equalized with the hot water.

In addition to a more efficient brew day, preheating strike water has reduced my propane usage and trips to refill propane tanks. I use the bucket heater to reduce the propane cost of heating my mash water: as soon as I mash in I filter the required sparge water volume and place the bucket heater in. It's not powerful enough to heat the 10 gallons of sparge water to I typically need for my 10 gallon batches in the hour it takes to mash but it helps.

1. It's safety-critical to ensure that the temperature controller can switch the current being used by the heating element. The ITC-308 is rated for 1000 W, the same as the power draw of the bucket heater I used. Even so, the power cord of the temperature controller was warm to the touch while heating. Failure to use a correctly-rated controller may cause a fire.↩

2. "Isn't it wasteful to run the heater for hours while you sleep?" When I first designed this heater setup I included a timer upstream from the temperature controller to turn it on a couple hours before I planned to begin brewing. I use a well-insulated cooler-style mash tun, though, which means that the heating element will run very little once the water reaches the set temperature. If you plan to use this setup with an uninsulated mash tun such as a stainless steel pot, you may want to add a timer. However, by my estimation, running the heater for 8+ hours in an insulated mash tun wasted less than a kilowatt-hour of electricity.↩