HERMS Questions

[atoughram]

Not sure if this is in the right forum - Move it as you see fit.

About ten years ago I built a triple sanke keg RIMS system, single pump, 2400W element running on 120V (So probably closer to 1000W), PID Controller, with the thermocouple in the MT. False bottom in the MT, out to the pump inlet, from pump into RIMS Chamber, through a ball valve to control flow, and back up to the top of the mash.

I can easily control mash temperatures to within a half a degree or better and can brew some really light colored beers.

BUT - It wont step mash in an acceptable amount of time. I can only get the temperature to raise at between 0.5 to 1.0 degrees f per minute. So, no protein rest, and no mash out. I've been really happy with the beers I've made, so I don't know if either step is really necessary.

I'm thinking about upgrading to HERMS operation. The thermocouple will stay in the same place, but instead of modulating the heating element, I'll modulate a pump. I'll run a copper coil in my HLT, pumping the mash through it to heat it. I'll add a element to my HLT and another PID controller to hold it's temp constant.

How fast will a HERMS setup like this raise the temperature of a mash totaling 10 gallons?

What temperature do you hold the HLT at? I assume 170f.

Would it be better for me to rewire my system and run the element on 220v?

Or.... I'm making good beer so don't change a thing...

 

[jeffmeh]

It's generally better to run the pump constantly and have the PID control the heat to the HLT. I don't run a HERMS, so I cannot really answer your question about the time required.

 

[PLOVE]

Why do you want to step mash? It's easy enough to do two infusions for protein rest and mash/starch conversion. Decoction mashing isn't really necessary with today's modified pilsner 2-row, though I'm sure I'll get an argument. If you are already brewing good light colored brews along the lines of a good european pilsner than I'd leave well enough alone and enjoy the beer you do brew.

FWIW I do have a 15 gal HERMS setup (6500W in the HLT with 1/2" copper coil). I'm not sure I can do much better than 1°/minute. Maybe with a smaller vessel it would be possible, but a HERMS is a heat-"Exchanger" and that's exactly what happens, your recirculating wort gets hotter, and your HEX get's cooler - towards an equilibrium. If you could add heat really quickly to your HEX it might work, but if your HEX is 10-11 gallons not so much. I actually thought this was one of the reason folks chose RIMS over HERMS; faster heating times. HERMS seems much better for stabilizing and holding temps for long periods of time.

Just my two cents.
P

 

[Yooper]

With such a small element, ramping up the temperature will take forever, sorry to say.

I had a 1500w element in my HLT, and it took way too long to even ramp up to mash out temperatures with a 5 gallon batch.

I changed it out to a 5500w element, and now it works perfectly! (It's a HERMS with the HEX in the HLT). I can ramp from 150 to 168 in less than 15 minutes for the entire (usually 25 pounds of grain + water) mash.

 

[BWN]

With such a small element, ramping up the temperature will take forever, sorry to say.

I had a 1500w element in my HLT, and it took way too long to even ramp up to mash out temperatures with a 5 gallon batch.

I changed it out to a 5500w element, and now it works perfectly! (It's a HERMS with the HEX in the HLT). I can ramp from 150 to 168 in less than 15 minutes for the entire (usually 25 pounds of grain + water) mash.

Are you saying you ramp up for you sparge? Or are you putting your whole volume in and increasing temperature after you mash? Sorry to hijack the thread. I always batch sparged before I went electric and am trying to get a handle on having such a sophisticated system. Just trying to figure out how everyone does this.

 

[mattd2]

... 2400W element running on 120V (So probably closer to 1000W),...
Would it be better for me to rewire my system and run the element on 220v?
...

It is more likely closer to 600W. I would expect this is the reason for the slow step changes.
You could either rewire for 240V or through a 5500W element in there (if it fits) = 1375W

 

[Yooper]

Are you saying you ramp up for you sparge? Or are you putting your whole volume in and increasing temperature after you mash? Sorry to hijack the thread. I always batch sparged before I went electric and am trying to get a handle on having such a sophisticated system. Just trying to figure out how everyone does this.

I usually do a mash out, before fly sparging. Since it's a HERMS, it's easy to just continuously recirculate and since fly sparging takes a long time, you want to "lock in" the mash profile. I'll ramp the temperature in the MLT to 168 by recirculating with the water in the HLT at 170 (I have a two degree differential between the temperature of the HLT and the temperature of the mash).

Even so, I still batch sparge sometimes! I go back and forth depending on how much time I have for the brewday and what I feel like doing. You certainly don't have to mash out with batch sparging but it's easy to do since I'm raising the temperature of the sparge water anyway and I'm recirculating anyway also.

 

[atoughram]

I made beer yesterday and it took four minutes to ramp up five degrees F. I guess the main thing I'd like to be able to do is mash out to 168-170f.

I'll have to measure the current flow on my element and see how much it's drawing to figure the actual wattage.

What I'm hearing is that a HERMS system wont raise mash temperatures any faster than than my current RIMS and since I don't have trouble with caramelization in my RIMS, I should leave it alone. I get more caramelization in the BK than in the MT.

 

[atoughram]

Why do you want to step mash?

HERMS seems much better for stabilizing and holding temps for long periods of time.

Just my two cents.
P

I'd like the ability to mash out. Currently it takes over ten minutes to raise the temperature from 148f to 168f. I'm not sure if it's all that important though.

My RIM's will hold the grain bed to within a degree, the thermocouple for the PID controller is in the grain bed, not the heater outlet.

 

[atoughram]

I changed it out to a 5500w element, and now it works perfectly! (It's a HERMS with the HEX in the HLT). I can ramp from 150 to 168 in less than 15 minutes for the entire (usually 25 pounds of grain + water) mash.

Is that the temperature of the grain bed? If so, what temperature are you running in the HLT? Are you modulating the HLT Temp or the pump with the PID controller?

In a perfect world, I'd run a motor operated valve off of the 4-20ma output of the PID controller and modulate the flow of wort to the HEX, but that valve is very expensive.

 

[atoughram]

It is more likely closer to 600W. I would expect this is the reason for the slow step changes.
You could either rewire for 240V or through a 5500W element in there (if it fits) = 1375W

How are you determining these wattage numbers?

 

[Yooper]

Is that the temperature of the grain bed? If so, what temperature are you running in the HLT? Are you modulating the HLT Temp or the pump with the PID controller?

In a perfect world, I'd run a motor operated valve off of the 4-20ma output of the PID controller and modulate the flow of wort to the HEX, but that valve is very expensive.

Yes, grainbed temperature. I'm ramping the temp in the HLT to 170 (which is fast with a 5500 w element) and then recirculating wide open. I use a PID for the HLT. I just use a ball valve on the output of my pump to control the recirculation speed, and to set the speed for the sparge.

My HEX coil is an old immersion chiller, 25' in length and coiled just above the element. I also have a stirrer with a little motor to circulate the water in the HLT.

 

[atoughram]

Yes, grainbed temperature. I'm ramping the temp in the HLT to 170 (which is fast with a 5500 w element) and then recirculating wide open. I use a PID for the HLT. I just use a ball valve on the output of my pump to control the recirculation speed, and to set the speed for the sparge.

My HEX coil is an old immersion chiller, 25' in length and coiled just above the element. I also have a stirrer with a little motor to circulate the water in the HLT.

Thanks! Good info!

 

[mattd2]

How are you determining these wattage numbers?

It is the way electrcity works If you half the Voltage you also get half the current flowing which results in a quarter of the power.

 

[atoughram]

It is the way electrcity works If you half the Voltage you also get half the current flowing which results in a quarter of the power.

Yes, in a DC circuit you are correct.

Works a bit different in an AC circuit - purely resistive loads versus capacitive and inductive loads screw up Ohms law. You have to determine the impedance before using Ohms law.

BUT - I wont argue with you, thats a good rule of thumb, thanks!

Next time I brew beer, I'll stick a clamp-on ammeter on my element and measure how much current is being drawn. I looked at 5500 watt elements and they look like they might fit in my RIMS tube. I've already got a 25A SSR controlling the element which ought to be adequate.

 

[mattd2]

Yes, in a DC circuit you are correct.

Works a bit different in an AC circuit - purely resistive loads versus capacitive and inductive loads screw up Ohms law. You have to determine the impedance before using Ohms law.

BUT - I wont argue with you, thats a good rule of thumb, thanks!

Next time I brew beer, I'll stick a clamp-on ammeter on my element and measure how much current is being drawn. I looked at 5500 watt elements and they look like they might fit in my RIMS tube. I've already got a 25A SSR controlling the element which ought to be adequate.

But isn't a resistive heating element a good approximation of a resitive load only. Would be intereting to see the acutal real world values for voltage and current compared with what is usually taken as the theoretical value on here.

 

[Yooper]

Next time I brew beer, I'll stick a clamp-on ammeter on my element and measure how much current is being drawn. I looked at 5500 watt elements and they look like they might fit in my RIMS tube. I've already got a 25A SSR controlling the element which ought to be adequate.

I don't have a RIMS, so this may be a different ballgame. But if you run a 5500 watt element wide open in a RIMS, I'd expect the wort to get over 170 as it goes through the RIMS (which you don't want) or still be slow to heat the whole batch unless you can hit 170 exactly and recirculate quickly. Scorching of the wort could be an issue in a RIMS with a 5500 w element!

 

[mattd2]

I don't have a RIMS, so this may be a different ballgame. But if you run a 5500 watt element wide open in a RIMS, I'd expect the wort to get over 170 as it goes through the RIMS (which you don't want) or still be slow to heat the whole batch unless you can hit 170 exactly and recirculate quickly. Scorching of the wort could be an issue in a RIMS with a 5500 w element!

Yeah, at a flowrate of 2qt/min (approx. 1 volume recirc'd in >10 mins - average 5 gallon batch) and 5500W I think you would see a 75 °F rise over the tube, @ 1375W that would be an 18°F rise. But remember that most electric RIMS tubes do have control over the output temperature though. But I hear what you are saying that 5500W might be overkill (unless you use it as a sparge water heater for fly sparging )

 

[atoughram]

But isn't a resistive heating element a good approximation of a resitive load only. Would be intereting to see the acutal real world values for voltage and current compared with what is usually taken as the theoretical value on here.

A carbon resistor is a purely resistive load. Wound wire heating elements tend to be inductive.

 

[mattd2]

A carbon resistor is a purely resistive load. Wound wire heating elements tend to be inductive.

I am very keen to see the results

 

[atoughram]

I am very keen to see the results

The results would be interesting - like I said - I'll measure the current on my element. But that doesn't tell the whole story either, the current lags the voltage. At least it did when I received my degree in electronics engineering...

But as I mentioned - Ohm's law comes close in an AC circuit at 60hz. I have a feeling that the impedance will be a bit higher than the measured resistance at 60hz therefore the wattage will even be less than 1/4 of 2400w and my assumption of near 1000w was flawed.

 

[mattd2]

The results would be interesting - like I said - I'll measure the current on my element. But that doesn't tell the whole story either, the current lags the voltage. At least it did when I received my degree in electronics engineering...

But as I mentioned - Ohm's law comes close in an AC circuit at 60hz. I have a feeling that the impedance will be a bit higher than the measured resistance at 60hz therefore the wattage will even be less than 1/4 of 2400w and my assumption of near 1000w was flawed.

Now you are just making me look like a dick for trying to explain how electricity works to an EE
Now this is coming from a Mech engineer, I would imagine that the impedence would be very low for a resistive heating element. the heat coming from the resistance of the wire, but having some impendence due to it being wound to fit more in. Would the manufacturers not try and minimise this impendence as much as possible to reduce the phase shift and thus the loss in power?
Now take me to school...

 

[atoughram]

Now you are just making me look like a dick for trying to explain how electricity works to an EE

I'm sorry.... That really wasn't my intention.

But you are right, I was making an assumption on the wattage of my element at 120vac without sitting down and figuring it out. Your numbers are obviously closer to reality than my assumption.

 

[atoughram]

Now take me to school...

Inductance reactance Calculation

Xl (Inductance Reactance) = 2(pie)fl

f = Frequency
l = Inductance in Henry's

Xc (Capacitive Reactance) = 1/(2(pie)fc)

c = capacitance in Farad's

So, total impedance is calculated using Pythagorean's Theorem

Z^2 = R^2 + X^2

X = Xc - Xl or Xl - Xc (Whichever gives a positive result)

Now that I've had to break out the books, I think I'll have a beer!

If you're ever in the states near Seattle, stop in for a beer, my treat!

 

[PLOVE]

I'd like the ability to mash out. Currently it takes over ten minutes to raise the temperature from 148f to 168f. I'm not sure if it's all that important though.

That's about how long it takes my HERMS to reach mash out temps. Seems to work fine. Would obviously like it to reach temps much faster, since I typically hold at 168 for another 10 min before starting sparge, but it is what it is. . .

P

 

[atoughram]

That's about how long it takes my HERMS to reach mash out temps. Seems to work fine. Would obviously like it to reach temps much faster, since I typically hold at 168 for another 10 min before starting sparge, but it is what it is. . .

P

So you have the same problem I do, slow temperature rise. I think I'll first try and wire my element for 220V and see how it effects my brew. If I remember correctly, I can set my temp controller to a PWM output so when it's holding a steady state, it might not scorch the wort.

 

[jeffmeh]

So you have the same problem I do, slow temperature rise. I think I'll first try and wire my element for 220V and see how it effects my brew. If I remember correctly, I can set my temp controller to a PWM output so when it's holding a steady state, it might not scorch the wort.

If you do increase the power to the RIMS, you should consider having the controller monitor temperature at the RIMS output. That will significantly reduce the likelihood of scorching.

 

[atoughram]

If you do increase the power to the RIMS, you should consider having the controller monitor temperature at the RIMS output. That will significantly reduce the likelihood of scorching.

Hmm... You just gave me an idea.... Build a second RIMS tube and put another identical element in there - two stage RIMS. That might get the temps up faster without scorching...