Stepping with a HERMS

[The Pol]

yeah... ultimately my educated guess is I'll do the exact same thing... but I'm still curious.

You said something earlier I wanted to ask you about though.... why does stirring the mash during recirculation defeat the purpose of a HERMS? Reflecting my probable ignorance... I thought the whole point of a HERMS was to simply constantly "mix" the mash by circulating the wort through it to get a more even and complete conversion. Why would actually mixing the mash during that process hurt?

Or are you simply saying you shouldn't have to mix it in the first place given the HERMS process?

I don't have a decent sparge arm yet (the ONE freakin thing I just haven't bothered to build) so two or three times during my mashing I'll give it a bit of a stir just to make sure I'm not channeling through it anywhere.

I am not certain, but I think I said it defeats some of the benefit. One great benefit to HERMS or RIMS is setting up a stellar grain bed and having crystal clear wort to start with. Obviously if you are stirring the grain bed, this will not occur.

 

[Cape Brewing]

Gotcha... makes sense.

I think I'm getting around that problem slightly with the manifold mounted underneath a false bottom. My false bottom doesn't fit my MT EXACTLY so I used some heat/food safe tubing to act as a gasket around the false bottom... and that doesn't fit exactly either so while 99% of my grain bed is held up by the false bottom, I do get grains around my manifold filtering as well.

It's a decent point though and I'll probably stop stirring as I get clsoe to finishing up the mash.. just so it'll clear completely.

 

[Liquidicem]

Do you think a jacketed MT might get MY set-up a bit closer to actually being able to do it?

Will it get you closer? Absolutely. Will it be enough? There is know why to know without going through a very detailed design and testing.

I work with several people who have spent the better part of 30 years designing jackets and jacket loops. It is not generally something you can just eyeball.

I think you are on the right path but you need to define a few more of you parameters or start building and actually test it before you'll get much closer to anything resembling an answer.

Good luck!

 

[The Pol]

There are a lot of great ideas... Id just like to see people build something. There are probably several rigs that could be built from this one thread alone... and maybe there would be a "better" HERMS solution.

Face it, stepping with a HERMS, though possible, aint easy, or there would not be this much discussion here or elsewhere about it.

 

[np0x]

IMHO a jacketed MLT will work if you get the jacket hot enough. Though I think that you will need a mash mixer to get the mash away from the hot walls of the MLT, I am not sure that a simple recirc of the wort will do it. Again, I dont know because I have never done it. But this is not a HERMS, this is a jacketed MLT.

I would do steam injection if I cared to actually do it...use an old pressure cooker, much more straightforward than building a jacketed MLT, albeit with it's own risks...kaboom...

 

[Lil' Sparky]

My $0.02

With past experience with step mashing it was easy to get 80% of the way to the next step but the last 20% takes time if you hold the wort temp to target + 2 degrees. Temperature stratification was not a big issue as the ramp up to the 80% of step temperature was in about 6-8 minutes, the next 5 minutes were taken up with the last 20% of the step.

I completely agree with this. Who cares if the mash is temporarily stratified during the step. We're only talking about a few minutes. As you get close to the target, there's not much stratification. This really bothers some people. Not me.

I agree with Bobby and some of the others that overshooting the target temp on the HEX is critical for quick steps. I don't think you'd want to overshoot by much, though, for the denaturing issue. What I don't know is how much higher is safe/advisable. Also, the closer the mash gets to the target, the less you should overshoot. This could be done in an automated manner, but it would take some custom programming for each system and probably some trial and error. Amazingly, it's pretty simple to do in an unautomated manner (as long as you can measure the out-temp from the HEX), and is one reason I'm considering NOT automating my system.

Stirring the mash. Why not during the step? I only see benefits here - such as reducing the stratification problem (if that's really a problem). The mash will reset and clear again after you stop stirring.

Jacketed MLT idea. It might work, but actually, I think using a coil inside the mash, like the iHERMS idea, would work better. A jacketed MLT will only apply heat to the outside of the mash. You would need a really good mash mixer, not just a go-round-and-round, design to help with this. A coil inside the mash is going to distribute the heat faster and more evenly. I still think you need a good mash mixer with this design, too, but it wouldn't be so critical to exchange the mash in a center-to-outside manner like with the jacket.

 

[The Pol]

See, then step mashing in a HERMS works for you. You are willing to accept the limitations that it inherently has. I mean, they may have no effect at all on a brew session.

But for me, being paranoid, a simple infusion that will bypass all of the possible limitations of a HERMS recirculating step, makes more sense.

Actual mileage may vary.

Results not typical.

Some limitations apply.

For a limited time only.


Etc.

 

[Seveneer]

I saw you mentioning this on the other thread... and that would be a much easier modification to my system then this jacketed idea. All I would have to do is change my PID to control temp exiting the HEX instead of the HLT itself.

... it just sounds counterintuitive..... that you would be be able to, at a slow flow rate, just heat to the desired temp as it exits the HEX and be able to step quickly. On what size batches?? (sorry.. you probably mentioned that in another thread and I missed)

I didn't say a "Slow flow rate", I said, "Reasonable flow". The reason I said this is that too fast a flow will result in a stuck/set mash

I make 10 imperial gallon batches and I recirculate continously throughout the mash.

If the mash bed is at 50C and I dial in 66C to the PID, the element in the heat exchanger will come on and heat the water bath up to what ever temperature is required to result in the wort exiting the HEX at 66C. Then it will maintain that temperature.

The element will bring the temperature of the recirculated wort to 66C in about 2 minutes while recirculating at my typical flow rate. At this point 66C wort is being deposited just beneath the surface of the mash.

Now assuming the flow is sufficient to recirculate the entire wort in 2-3 minutes that gives roughly 2.5 changes of wort at the 66C within a 10 minute period.

This is where you have to decide whether or not this is fast enough of a step for you. I suppose it's more of a ramp but don't tell The Pol

In my experience this is enough to raise the temperature of the mash to the desired 66C.

/Phil.

 

[lamarguy]

Jacketed MLT idea. It might work, but actually, I think using a coil inside the mash, like the iHERMS idea, would work better. A jacketed MLT will only apply heat to the outside of the mash. You would need a really good mash mixer, not just a go-round-and-round, design to help with this. A coil inside the mash is going to distribute the heat faster and more evenly. I still think you need a good mash mixer with this design, too.

Ya, I gave the same recommendation. Assuming the inner coil is large enough to evenly distribute the heat, you should be able to induce a large temperature differential between the HLT and MLT to achieve time efficient step mashing.

And, like you said, stirring during step-ups will be necessary to evenly heat the inner mash. That is, unless you go with a "rib cage" style copper heat exchanger and/or add a second pump to just recirculate the mash.

 

[caskconditioned]

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.

 

[Cape Brewing]

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.

 

[Cape Brewing]

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

What about a heated mash mixer? .

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.

 

[Lil' Sparky]

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.

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?

 

[Cape Brewing]

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

... 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.

 

[Catt22]

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.

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.

 

[kladue]

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.

 

[Catt22]

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.

 

[leboeuf]

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

 

[np0x]

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...

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.

 

[pompeiisneaks]

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?

 

[Denny's Evil Concoctions]

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?

 

[Catt22]

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).

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.

 

[Bobby_M]

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?

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.

 

[silvervan83]

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.

 

[Lil' Sparky]

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.

 

[The Pol]

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.

 

[Lil' Sparky]

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.

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.

 

[Catt22]

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.

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.

 

[The Pol]

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!

 

[Denny's Evil Concoctions]

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!

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

Or perhaps Midas Touch?