HERMS HLT Temperature Question - Where To Keep It At Post- Dough In for Multi Step Mash

[awoitte]

I got my HERMS setup the way I want it (for now).

Let's say I'm mashing an altbier recipe and the starting dough-in is supposed to begin @ 100'F, and then multiple step mashes. For the sake of this discussion let's say that I have targets of 120, 140, 148, 156, and then a 170 mashout.

Is keeping the HLT water temp at 170'F for all raises altering my grain in a negative manner by having the liquid going through the coil at that temp for a brief period of time? Or is it diluting fast enough once it goes back into the mash tun that the grain isn't affected? Is there a higher/lower temp (or a specific difference) that it should be to bring the mash up to desired temps?

I feel like my process now is taking too long to bring the mash up to the temperatures I want to hit. For example, if I want to hit 140 (and maintain it for ~20 minutes), the mash sits between 120-139 for 15 minutes before hitting the next step, and then at that point I don't know if I'm supposed to be starting the clock them, or before when it was near/within range...

Additionally, if I'm using a hotter temperature in my HLT, once I hit my target 140'F, do I stop circulation for the 20 minutes so it doesn't continue to get hotter? And If I stop the circulation for the time being, what happens to the liquid that's resting in the coil in my HLT?

Suppose I'm a little confused on how to properly maintain temps the best way with HERMS.

Cheers

 

[day_trippr]

A blend valve, a pair of tees, and a bit of high temp tubing, would probably let you do exactly what you're thinking

Knowing your system specs and batch size/total grain weight might be illuminating. Or not.

I do 10 gallon batches on a 3v2p single tier rig with a 50' 1/2" ID ss hex that takes 12 gallons in the hlt to fully cover. Without being really aggressive with the hlt burner, that 12 gallons will rise at 2°F per minute. And at a flow rate between 2 and 3 gallons per minute I can get close to a +1.5°F slope in a typical, 60 point mash (roughly 20 pounds of grain). Otoh, my 44 pound imperial stout slope is well under 1°F.

I would be wary of getting cute with the recirculation through a hot hex. All of the wort in the hex would be denatured every time you stopped the pump, at the least, and it just sounds like risking a batch pretty much every time you brew.

I spitball the step duration based on the ramp to get there. If it takes 15 minutes to get to a "20 minute rest" I'll stay on temp for 10 minutes, then move on...

Cheers!

 

[awoitte]

3 vessel single tier system, most of my brews have been 5 gallon batches but I ramp them up due to loss through pumps, cf chiller, racking off trub, etc. So I usually begin my boil with about 7.5 gallons.

I went big because I plan on starting to do 10 gallon batches, so I have 20 gallon kettles. To be covered my coil requires ~17 gallons full.

Sorry, but I'm not sure what you're referencing when you say "gettin cute".

Still looking for confirmation on temp questions

A blend valve, a pair of tees, and a bit of high temp tubing, would probably let you do exactly what you're thinking

I spitball the step duration based on the ramp to get there. If it takes 15 minutes to get to a "20 minute rest" I'll stay on temp for 10 minutes, then move on...

Cheers!

How do you stay on temp for 10 minutes while recirculating unless your HLT is regulated to match the same temp as your desired rest? And if that's what you're doing, isn't it taking much longer to get up to your next rest temp?

 

[day_trippr]

I do hold the hlt ramp when "resting". There is always a ~1.5°F differential between my hex exit temperature and the mash target, so if I'm resting at 130°F I'll hold the hlt at 131.5°F. Yes, that mean moving forward means bringing the hlt bath from there up to the next step.

Cute - meaning your thoughts about just sticking the hlt at 170°F, then controlling the mlt temperature by recirculation speed.
It won't work, which is why nobody does that. Again, you stop the flow and everything in the hex denatures. Bad juju, not what we're usually going for. And it takes lots of recirculation to shift a mash, so the top of the bed is going to get cooked before the bottom reaches the next step.

fwiw, aside from the sach rest and mash-out, the only rests I do are for brews using a high wheat content - like 45-50% as in the raspberry wheat base I brewed Friday...

Cheers!

 

[awoitte]

And it takes lots of recirculation to shift a mash, so the top of the bed is going to get cooked before the bottom reaches the next step.
Cheers!

But I thought you were able to raise it 2'F per minute? That doesn't sound like a lot of recirculation time to shift the mash...

So to clarify, what you're saying is (in my above example), you'd dough in and get the mash at 100 (while keeping your HLT at 101.5 during the recirc), and then for a 20 minute rest at 120, you'd continue to recirc while raising (then keeping) your HLT to 121.5, then for the next rest raise and hold steady at 141.5, and so on?

 

[day_trippr]

Notice I conditioned my rig's mash ramp rate as a function of the grain mass - my usual beers are half the grain mass of my imperial stout - with the former enjoying the quicker ramp.

Anyway, fitting the way my system works to your series of steps, I would heat up my strike volume to the temperature BeerSmith says my equipment and grain bill temperatures would result in a 100 degree mash temperature (btw, I heat the strike volume in my bk while the hlt is getting to where it needs to be separately) while the hlt would be set to 101.5.

I'd let the strike settle for a few minutes, then give the mash one thorough stir, lid the mlt and let it sit for another 15 minutes, then heat the hlt to the next step +1.5 degrees. And so on.

That's the best my system can manage without doing something that puts the fermentability of the wort at risk...

Cheers!

 

[augiedoggy]

Mash conversion occurs in the liquid not the actual grain itself... if you exposing even some of the mash to higher temps than the conversion of that liquid will occur at those temps.. this includes denaturing of enzymes which is even easier to do if one has an incorrectly setup or used rims system. The result is lower conversion efficiency.

As day tripper mentioned the correct way to utilize herms is with controling the heat exchangers temp (AKA HLT water here) not recirculation speed which will only contribute to other issues like channeling.

Rims has a large advantage to Herms for step mashing.. They both have their strong points but this is not one for Herms compared to a well implemented Rims system..