HERMS Rise Time

Hey everybody,

I built a HERMS system to brew 5 gallon batches. It consists of a 50ft length of 1/2" copper tubing mounted in an 8 gallon stainless steel pot with a 1500w heating element hooked up to a Johnson temperature controller that measures the temperature at the outflow of my 10gal igloo cooler mash tun. Yesterday I brewed a 5 gallon batch of a Belgian Golden Strong Ale with a 3 step mash profile (the first at 140°, the second at 154°, and a mashout at 168°). However, the rise time between the three steps was 52 minutes, which is wayyyyyyyy too long. I have been told that 1500w should be sufficient for a system of that size, but I am wondering if that was bad advice. If it is not the heating element, could it be that I am losing heat via the silicone tubing? I have quite a lot of it, as it basically is a 3 tiered system and I use silicone tubing to connect everything together (I would estimate that the wort has to travel through 20 feet of tubing to make a full cycle through the system). If that is the case, would it help for me to cover them in aluminum tape to act as insulation and if not, what would you recommend? Are there any other things that might contribute to this that I can change? Thanks everybody for all the help!

1500W is fine for maintaining, but it's definitely a bit slow for raising 8gal quickly. Insulating the pot and hose would help, sure. For the hose you could run to Home Depot and buy those black pipe insulators.

Honestly though step-mash/rising with HERMS just isn't very quick, even if you have a stronger element.

iijakii said:

1500W is fine for maintaining, but it's definitely a bit slow for raising 8gal quickly. Insulating the pot and hose would help, sure. For the hose you could run to Home Depot and buy those black pipe insulators.

Honestly though step-mash/rising with HERMS just isn't very quick, even if you have a stronger element.

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Thanks for the reply. would I be better off abandoning the HERMS system and going to RIMS instead or doing something else entirely? Also, is there a problem with having such lengthy rise times (aside from the obvious one of it lengthening my brew day)?

My old system had a similar external HERMs coil and I was able to raise temps sufficiently for step mashes with a 2000 watt element. You'll never get blazing speed but a degree per 1-2 minutes. have the shortest run of non insulated hose you can and things will get much better, insulate that hose and you'll see a huge difference

edit.... if I get you right, you're using an 8 gallon pot with the HERMS coil separate?

Bellybuster said:

My old system had a similar external HERMs coil and I was able to raise temps sufficiently for step mashes with a 2000 watt element. You'll never get blazing speed but a degree per 1-2 minutes. have the shortest run of non insulated hose you can and things will get much better, insulate that hose and you'll see a huge difference

edit.... if I get you right, you're using an 8 gallon pot with the HERMS coil separate?

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No, my 8 gallon pot is my HLT and my HERMS coil is mounted inside of it

Normans54 said:

Thanks for the reply. would I be better off abandoning the HERMS system and going to RIMS instead or doing something else entirely? Also, is there a problem with having such lengthy rise times (aside from the obvious one of it lengthening my brew day)?

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I'd like to know this too as I have been debating between HERMS and RIMS about be using a 1500w or 2000w heater in a similar amount of water.

8 gallons is about 30 litres of water.
Specific heat capacity of water 4200 J per deg C per litre.
1 Watt = 1J/s

So, to raise 30 litres of water 1 deg C, you'd need to apply 4200*30 = 126000 J.
Divide this by 1.8 to get to Fahrenheit (126000 / 1.8 = 70000 J).

You have a 1500 Watt heater, that means it takes 70000 / 1500 = 46 seconds to heat the 8 gallons 1 deg F, not including any losses.
The losses however will be significant (both from the mashtun, HLT and hoses), so you'd probably be well over a minute per deg F.

As previously stated, a HERMS setup might not be ideal for step mashing, but on the other hand, why step mash? And if you really want to step mash, then infusions might be the answer. HERMS and RIMS, while possible to design to do step mashes, are really about maintaining a constant temperature through the entire grain bed.

alphaomega said:

why step mash?

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Hefeweizens are enough reason for me, personally.

alphaomega said:

HERMS and RIMS, while possible to design to do step mashes, are really about maintaining a constant temperature through the entire grain bed.

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I feel like this gets said a lot, but I don't see the logic in it. It's entirely reasonable to step up a recirculating mash with a RIMS tube if you don't have enough height below your false bottom to cram one in there. The regulator just does whatever it needs to do to get the exit temp to be the target. It can adjust the duty cycle to raise just as easy as it can adjust it to maintain, no?

Not trying to be snarky or rude, apologies if it comes off that way. Thanks for the math!

Fair enough. Still, infusions are easy and fast.

I also said it is possible.
You just need to balance on the edge of putting in as much heat as possible, with as high flow as possible, without scorching or denaturing enzymes by overshooting too much or compacting the grain bed. Still, you won't be able to 'step' mash, but may have an acceptable 'ramp' mash.

What would be your acceptable rise in degrees per minute? The math is quite easy.
I would gues that if you do steps on a regular basis you're gonna want at least 3500 watts or switch to RIMS

I used to have a 1500w element in my first electric system. It took 90 minutes to get to strike temperatures (usually 4-5 gallons). I could never step mash or mash out with that.

Now I have a 5500w element, and it heats fast, if I want it to. I have a PID on it, so I can go very fast to a step temperature, or slower to a mash out. I normally don't turn it down, and just heat it at 100% power, so it's not really that important to have the PID.

I found that step mashing was impossible with a 1500w element, even with a smaller batch size. It just took way too long to reach the next temperature.

If step mashing is important to you, then a bigger element has to be the way to go in a HERMS. I never used a RIMS but that would be fine, if you made sure to recirculate well and not scorch the wort in the RIMS or otherwise get it too hot.

Yooper said:

I used to have a 1500w element in my first electric system. It took 90 minutes to get to strike temperatures (usually 4-5 gallons). I could never step mash or mash out with that.

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Out of curiosity, was this system RIMS or HERMS?

angrybits said:

Out of curiosity, was this system RIMS or HERMS?

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HERMS. I always have had HERMS, and never tried a RIMS.