Brautag: HERMS Trio Standard

Brew Day with the HERMS Trio Standard

In this post we'll have a look at what it's like to brew with the HERMS Trio (Standard Version). I'll be brewing a lighter batch of my Tropicana IPA, just in time for the warm weather.

The HERMS Trio Standard is a traditional 3 vessel HERMS (Heat Exchange Recirculating Mash System). During the mash we recirculate the wort through a heat exchanger in our hot liquor tank. This type of system provides very good control over mash parameters and a very clear wort in the kettle. And the design is fairly simple:

HLT on the left
MLT in the middle
BK on the right

On the left we have our hot liquor tank (HLT), including a heating element and the heat exchanger coil. There is also a dip tube (out), whirlpool tube (in), and a thermowell. The thermowell is not strictly necessary because we will be using a different temperature sensor to control the mash temperature, but it is nice to have. In the middle is the mash/lauter tun. The false bottom sits on the low stand, the adjustable height sparge arm returns the wort gently onto the grain bed. There is also a thermometer installed, this is just for quick reference and again, is not strictly necessary. On the right is the boil kettle, here we have the second heating element, a dip tube, whirlpool tube, thermowell, and port for the steam condenser.

The position of the HLT and BK can be switched so that the HLT is on the right of the MLT.

The HERMS Trio Standard setup for mashing.

The first step (after assembling everything) is to add your strike water to the MLT, the sparge water to the HLT, and turn on the pumps and heater in the HLT. For strike water volume, I calculate my desired volume using 2.5L/KG and added 3L to that to account for what is underneath the false bottom and in the coil while recirculating.

After the system has reached my target setpoint - desired mash rest temperature plus 2C - it's time to add the milled grains. I like to remove the sparge arm to help while stirring in the grains. Don't forget to turn off MLT pump and the heating element in the HLT; when the wort is not recirculating there is no accurate temperature control.

Doughing In
Start of recirculation
End of mash


I let the grains rest for a few minutes before slowly turning on the pump again, and then the HLT heating element. You can see how clear the wort is at the end of the 60 mash rest (picture on the right).

Now it's time for the first hose change. We want to put the output of the MLT pump onto the boil kettle whirlpool inlet, and the output of the HLT pump onto the input of the HERMS coil. By sparging with clear water through the HERMS coil, the coil will be more or less clean when we are done.

sparge water is pumped slowly over the grain bed in the MLT

We maintain the same flow rate while pumping wort out of the MLT into the brew kettle.

A sparge flow rate of about 1 L/min is pretty standard when sparging. We use the ball valves on the output side of the pump to control the flow rate of sparge water into the MLT as well as wort into the brew kettle. I keep about 5cm of water over the grain bed when I am sparging. As soon as the heating element in the boil kettle is covered, I start heating the wort to boil temperature. There is a lot more water in the HLT than I need for brewing, so I pretty much just sparge until I hit my desired brew kettle volume.

When the kettle volume is reached, it's time to turn off the pumps and start with some preliminary clean up. But first another hose change to prepare for after the boil: this time we move the pump group from the MLT to the boil kettle, so we can use it to whirlpool the wort. The pump including the elbow is clamped onto the boil kettle output valve. If you want to use the pump to fill your fermenter, take one of the ball valves from the HLT and clamp it to the pump output. This way, you can disconnect the whirlpool hose and use it to fill your fermenter, while still having flow rate control out of the pump.

What about those hose changes? Well, they keep the design very simple. And with Tri-Clamp its also very easy to do! A short video demonstrates making the changes:

While the wort is boiling, I prepare the hop additions and finish the initial cleanup. The HLT with its attached pump and fittings is clean, and only needs to be drained and dried. I still like to remove all the fittings from the outside of the kettle to make sure it dries completely, but I do tend to leave the HERMS coil mounted in the kettle. The MLT can be removed for cleaning now too. When that's done all that's left at the end of the brew day is the clean the boil kettle with its pump and fittings.

Boiling the wort. the optional steam condenser is attached to the kettle sidewall.


After a 90 minute boil I turned off the heater, placed my immersion chiller in the kettle, and recirculated briefly to disinfect the pump and attached fittings. Try not to run boiling wort through the pump, this can cause cavitation and is not good for the pump! Wait until the temp reaches 96-97C to begin recirculation. I cooled the wort to 80C and added a hefty hop addition for whirlpooling. After letting the whirlpool run for 20 minutes I finished cooling the wort to 20C, removed the immersion chiller, and let everything settle out. Then it was just a matter of filling my fermenter and finishing the cleanup.

Keg fermenter (right) fitted with blow off tube to the serving keg (left) which will be purged with CO2 during fermentation. Temperature control is done via the thermowell in a converted freezer.

Without going into much detail, suffice to say I really like fermenting in corny kegs. My plan is to add a dry hop charge at about 1-2P above my target finishing gravity, and install a spunding valve to begin carbonation. At this point it is a completely closed system. When fermentation is done, a cold crash helps settle everything out. The fermenter has a floating dip tube installed (top draw) to help keep trub and hops out of the serving keg when transferring (using counterpressure to reduce foaming) in the serving keg. Once the transfer is done, the beer is ready to enjoy. I promise a full blog article in the future on fermentation using corny kegs!

Another successful brew day is complete! I really enjoyed this one today on the HERMS Trio Standard, because I used to brew on a system exactly like this one for well over a year.


Back to blog

Leave a comment

Please note, comments need to be approved before they are published.