Stepping with a HERMS

I'm guessing you're right on the need to mix the mash if you're going to jacket the MT... I was originally thinking that you wouldn't need to because you would be increasing temp from two sources... 1) the jacket that would get the outter edges and 2) continuously recircing through a HEX in the MLT that would heat the rest.

Under this scenario... as long as you're recircing and turning the entire volume over reasonably quickly, I wasn't thinking you would need to mix anything.
The overall flow of wort through the grainbed would do the mixing.

caskconditioned said:

Just to throw another wild idea into the mix...

What about a heated mash mixer? .

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Nah... that's stupid.

I'm joking! How would you heat a mash mixer? Make the rakes out of copper 1/2" and then actually recirc through it like a submerged sparge arm?

I think someone tossed that out there.

caskconditioned said:

Just to throw another wild idea into the mix...

What about a heated mash mixer? You could mix and heat the mash while recirculating. Once the steps are completed, you recirculate as normal to clear the wort and set the grain bed.

I do step mashes so rarely that I'm really following this post (and the others) out of sheer curiosity.

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Oooo, that's an interesting idea. I'm envisioning not a round-and-round mixer, but more of an vertical eliptical motion - a rigid coil connected to an arm on a motor similar to a piston connecting rod. Anyone follow?

Lil' Sparky said:

What I don't know is how much higher is safe/advisable.

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... and that seems to be the million dollar question on any thread that has to do with this topic.

For the purpose of this thread, I've been simply assuming that you don't want to overshoot at all... (again... just for arguments sake) and then seeing what folks have for ideas to acheive the step in the quickest way possible.

- control the HLT temp via a measurement of the wort exiting the HEX..
- my crazy jacket idea
- coils in the MT/coils in the HLT/coils in both
- screw it.. just overshoot
- heated mash mixer
- why make it complicated... just do an infusion...

they've all been tossed out there... I think it's been helpful to at least kick ideas around.

Cape Brewing said:

I'm guessing you're right on the need to mix the mash if you're going to jacket the MT... I was originally thinking that you wouldn't need to because you would be increasing temp from two sources... 1) the jacket that would get the outter edges and 2) continuously recircing through a HEX in the MLT that would heat the rest.

Under this scenario... as long as you're recircing and turning the entire volume over reasonably quickly, I wasn't thinking you would need to mix anything.
The overall flow of wort through the grainbed would do the mixing.

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I agree that circulating the wort continuously largely eliminates the need to stir the mash. I also agree that turning over the entire mash volume reasonably quickly is important. I will go even further and say the faster the better short of a stuck mash. I'm using a direct fired RIMS though.

The jacketed tun should operate much the same way regarding the circulation of heated wort keeping the mash temp uniform and stable. The large surface area of the wrapped coils should be able to distribute a lot of heat gently over a large area. That might be the biggest advantage of all. I think it would work, but might be also be a big hassle to deal with overall. It's an interesting idea.

It looks like the big question is where is the enzyme activity, the circulating wort or the mash. If it is in the circulating wort then the leaving temperature is all that is critical, if it is in the mash then long steps might be a problem.

The enzyme activity is in both the mash grain bed and the circulating wort. They are in solution and move with the wort. So does everything else that is soluble. I avoid overheating the wort by monitoring the return temperature. I simply apply heat while circulating for ramp ups and monitoring the return temp adjusting the flame as needed which isn't usually much. I circulate fast.

With no overshoot, a HERMS will never be able to step quickly enough to justify step mashing. This is just the way control theory works... I haven't crunched the math so I can't say how much overshoot you would need to make it viable.

The biggest pita with this setup would be the need to heat and cool your HEX in order to reign in a certain temp. It seems no one ever mentions the need to cool the HEX in these discussions...

This is why The_Pol strongly objects to the HERMS step mash. His HEX is fully insulated and is meant to hold a certain temp. Any overshoot in his system would lead to catastrophic control system failure.

I also agree that this is most likely more trouble than it's worth. You would have to compensate for too many variables. I built a fluid heating control system back in the day and it was a real challenge to keep overshoot within our lab's specs to meet decent temp rise times. The HERMS brewer has much more on their plate to deal with with the intermediate HEX and then the wort being an intermediate HEX with the grain mass....

Tom

leboeuf said:

The biggest pita with this setup would be the need to heat and cool your HEX in order to reign in a certain temp. It seems no one ever mentions the need to cool the HEX in these discussions...

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The need to cool your hex would result from a large volume, i only have about 1.5 gallons of water in my entire hot side of my hex, so any contained heat is rapidly absorbed with very little overshoot, plus PID control also avoids overshoot. If you have a giant vessel and differential control, well that's going to end differently.

Okay, Now I'm getting lost in all the details of this thread, but I want to ask a question... Why is heating the wort so bad, if the common german practice of decoctions is so popular... they BOIL the freaking wort and readd it to the mix... meaning they take out a small sample, boil it, and add boiling wort back into the mash... How is that NOT heating past the temps you want to mash at? I use HERMS, and the beer I've got from it tastes awesome, and like beer... what's wrong w/ it? I didn't do a step, but I'm pumping 150ish wort into a 180ish HLT and dumping it back in the top at hot temps maybe 170? And it still works great... so what am I missing from this concept?

I'll let the decoctionists deal with that question.

I've been thinking of inserting coils into the mash like my iHERMS idea, but instead of using two pumps, using just one and pumping the mash liquid though the hex and the MLT coils and then though the sparge arm to heat more evenly. While I think with the iHERMS you could heat faster as you really have two heat sources, I think this would help keep the mash temp even.

As for overheating the outlet. I've been doing some reading as to how long it takes to denature. Much longer than most think. The problem isn't really denaturing. Its that even a 1 deg diff in Temp effects beta and alpha amylase activity.

If you are returning mash at 160 but your target is 150 and your mash bed is at 140 (say stepping from a gum rest for a wheat), then what ever enzymes in the exchanger are working like it's 160 (alpha range), and the bottom of your mash bed is working at 140 (beta).

How does this effect the finished product?

Denny's Evil Concoctions said:

If you are returning mash at 160 but your target is 150 and your mash bed is at 140 (say stepping from a gum rest for a wheat), then what ever enzymes in the exchanger are working like it's 160 (alpha range), and the bottom of your mash bed is working at 140 (beta).

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Man, that's a huge spread from 160 down to 140! I never have that much of a difference. When doing a ramp up from 140 to 150 I would just turn up the flame and watch the returning wort temp climb the target in about five or six minutes. No big deal. I know that I am able to turn over the entire mash volume in a couple of minutes or less and it's easy to maintain a stable mash temp at a very, very low flame once it gets there. I can see how overheating the wort in the HEX could be a problem with a HERMS and that is one of the reasons I haven't built one. I've never quite been sold on the design principle.

pompeiisneaks said:

Okay, Now I'm getting lost in all the details of this thread, but I want to ask a question... Why is heating the wort so bad, if the common german practice of decoctions is so popular... they BOIL the freaking wort and readd it to the mix... meaning they take out a small sample, boil it, and add boiling wort back into the mash... How is that NOT heating past the temps you want to mash at? I use HERMS, and the beer I've got from it tastes awesome, and like beer... what's wrong w/ it? I didn't do a step, but I'm pumping 150ish wort into a 180ish HLT and dumping it back in the top at hot temps maybe 170? And it still works great... so what am I missing from this concept?

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If you consider the smaller portion of the mash that is removed during a decoction you'll see that the bulk of the enzymes are not denatured. We're talking about running the entire volume of wort through the HEX at least a few times. In any case, I think that the short time that the wort temp stays elevated says that the overall effect on the enzymes is negligible.

There is still a valid point raised about halting the heating process in the presence of elevated HLT temps. I threw out the idea that a second controller could halt recirculation by killing the pump when the output of the MLT reaches the setpoint. It adds complexity and cost for sure. If your HLT is where your HEX is and you're concerned about dropping the temp for the sparge, you can add a gallon of cold water but now you're killing some of your automation.

Man... You guys are all nutz. JK

I don't see how dumping 160 wort on top of a 145 grain bed is that much different from dumping 3 or 4 quarts of boiling water on the grain bed. Beta and alpha aside there needs to be SOME overshooting to get the step done.

If a coil were jacketing the MLT then the water running through it would have to overshoot the target temp to get the mash where it needs to be. The outside walls of the MLT would then be 2-3-5-8-10? degrees higher than the target and that much hotter than the wort in the middle. Even with good stirring the walls would still be at a higher temp.

I step with my HERMS all the time and my beer tastes just fine. I just think if you have a HERMS and want to step, then use it accordingly.

silvervan83 - I'm right there with you. If you want to do this with HERMS/RIMS/PICK_YOUR_FAVORITE_SYSTEM, then you have to overshoot a little (or maybe a lot in some cases), and guess what - your beer will be just fine. Ask all the brewers that do it all the time.

Yah, like I have said, you CAN step with a HERMS, RIMS or by placing the MLT in the sun. If you are willing to accept the variables, you can do anything. If I step I want a couple things:

#1. A step from 122F to 155F in 10 minutes or less
#2. I want my MLT temp. homogenous, I mean, it is a HERMS, that is important to me.
#3. I want to be able to assure the same step up time/profile across different brews. (read grain bills/mash volumes)

I couldnt make this happen, so for ME it was easier to flip a light switch and watch a sight guage and infuse the MLT with a couple gallons of water.

I used to mash in a single cooler in my kitchen too, but I didnt like some of the variables in that process either, so I have HERMS. Single infusion mashing is great, but again, I didnt want to settle on the variables.

Bobby_M said:

There is still a valid point raised about halting the heating process in the presence of elevated HLT temps. I threw out the idea that a second controller could halt recirculation by killing the pump when the output of the MLT reaches the setpoint. It adds complexity and cost for sure. If your HLT is where your HEX is and you're concerned about dropping the temp for the sparge, you can add a gallon of cold water but now you're killing some of your automation.

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Nobody said this stuff HAS to be automated. I think we've got several guys around here w/ non-automated HERMS/DF-RIMS that do this stuff w/out any problems.

Lil' Sparky said:

Nobody said this stuff HAS to be automated. I think we've got several guys around here w/ non-automated HERMS/DF-RIMS that do this stuff w/out any problems.

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Absolutely right! My RIMS is manual control all the way and w/out any problems and it's versatile. I haven't seen the need to automate things. Manual control is easy and effective. I like to stay a little more involved in the process. A robotic brewery just isn't my style.

My whole plan was to set it and forget it... I am as close to that as I will ever get. I dont like to be overly involved, because I make mistakes, A LOT of them. The less involved I am, the better my beer tastes!

The Pol said:

My whole plan was to set it and forget it... I am as close to that as I will ever get. I dont like to be overly involved, because I make mistakes, A LOT of them. The less involved I am, the better my beer tastes!

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Sure you shouldn't change your username to Lazy Brewer?

Or perhaps Midas Touch?