HERMS Strike Temp = Mash Temp?

[241]

Hi, I just built a HERMS system and completed my first brew day on it.

I noticed that when Kal gets ready to dough in, he just waits for the temp in the MLT to read the target mash temp and then mashes in.

Here's what he says:

Once both the Hot Liquor Tank and Mash/Lauter Tun PIDs read 149F (our mash temperature), it's time to add the 18 pounds of grain.

I had been so used to factoring in heat loss due to grain temp that when I mashed in at ~160F (in the MLT and HLT) for a mash temp of 153F it way overshot my temperatures because of the temperature in the HLT.

My question is - how do you HERMS guys handle your strike temp? Do you just set it to your target mash temp and once you hit it, dough in?

How long does it take you to get the mash temp back up to where you want it to be after heat loss from the grain?

Thanks!

 

[mascervesa]

For a single infusion mash, I usually have the strike water at 168 ° F or so (depending on grain weight, water volume, and temperature) in the Mash tun and add then add the grain. The mash equalizes to the mash temperature and the water in the HLT is at or slightly above mash temp. Once the wort is circulated in the HERMS coil, mash temp is quickly maintained. IMO, 160° F seem too low.

 

[mascervesa]

To clarify, I heat the strike water in the BK and pump in the mash tun. The HLT water is at 153°F in this case, so that the HLT and MLT are about equal, and the PID's take over from there.

 

[Bobby_M]

In a HERMS, you're about to start recirculating the mash through a coil that is in the HLT and that water will be whatever the strike temp was.

If you want to dough in at a higher strike temp so that you can nail your temps from go is to use that raised temp for strike (165F) and then as soon as you dough in, top up the HLT with room temp water until you hit your mash temp in that vessel as well. Then you can start recirculating.

Yes, you can use your Boil kettle for the initial strike also.

 

[GotPushrods]

Just think of all the water in your system as the strike volume.

In my case it's a full-volume 2-vessel system. Generally around 15 gallons of mash strike and 12 in the HLT/BK. Since the mash is heat-exchanging w/ the HLT, essentially I have 27 gallons water to consider.

If I'm shooting for 150, 151 or 152 is about right. It's such a small difference I can see why Kal would just use mash temp.

 

[241]

Thanks guys.

I did debate on whether or not to use the boil kettle for strike water, but the laziness kicked in and I wanted to utilize the automation as much as possible.

I also noticed a HLT temp of ~155F netted me consistent readings of ~153F in the MLT. I may just strike above my targeted mash temp by 2F next brew day and see how long it takes to get mash temp to come back up to 153F. Judging by how quickly it overshot on the last brew day, it should be pretty darn quick.

 

[bcrawfo2]

This is very timely. I'm still dialing in my HERMS system.
I heat my mash water by circulating thru my herms...just easier.
I wonder if we can develop a similar formula to what beersmith does to calculate the HLT temp?
I'm using rough numbers here...
If you have 10 gallons in your HLT...that's about 80 pounds
You also have 5 gallons in your mashtun/herms...that's about 140 pounds.
Then...you add 12 pounds of grain at 65 degrees.
Finally...if your desired mash temp was 150....can't we figure out the starting temp needed? At least close?

As I started to try to figure this out in Excel...I thought...why can't I just use a traditional strike water calculator and set my water volume to be both the mash tun and the HLT. But...the problem is the lag between the volume of HLT water ramping up the mash.
Sorry for my ramblings.

 

[241]

This is very timely. I'm still dialing in my HERMS system.
I heat my mash water by circulating thru my herms...just easier.
I wonder if we can develop a similar formula to what beersmith does to calculate the HLT temp?
I'm using rough numbers here...
If you have 10 gallons in your HLT...that's about 80 pounds
You also have 5 gallons in your mashtun/herms...that's about 140 pounds.
Then...you add 12 pounds of grain at 65 degrees.
Finally...if your desired mash temp was 150....can't we figure out the starting temp needed? At least close?

As I started to try to figure this out in Excel...I thought...why can't I just use a traditional strike water calculator and set my water volume to be both the mash tun and the HLT. But...the problem is the lag between the volume of HLT water ramping up the mash.
Sorry for my ramblings.

Hm not sure about that. I did brew again since this post and found great success with just using my target mash temp as my strike temp. After recirculating began once doughed in the temp went from 143 back up to 152 in only a few minutes

 

[Roadie]

A few times I've recirculated strike water through the mash tun to warm the kettle prior to dough in where I can have the HLT/MLT close to the same temp but usually I just aim for about an 8 degree temp differential which by the time I'm done stirring the grain brings me in about where I need to be. During the mash I keep an eye on the MLT temp on the panel and end up lowering my HLT temp a little at a time to stay where I need to be.

 

[Yooper]

My grain is generally about 55-70 degrees, and drops the temperature of the water by about 13 degrees, even with the HERMS. I'm sure the HERMS will 'catch up' but I strike with water about 13 degrees warmer, and then by the time I am all stirred up and break up all the doughballs (maris otter seems to make a bazillion doughballs), I'm right at mash temp and the HERMS keeps it there.

 

[maierhof]

Congrats on making the move to HERMS - you are going to really love this method as soon as you get to know your system.
BTW - I asked the same question when I first got mine going...

To me - it really depends on what you are brewing.
If you are doing a lager and want to do a few steps, or if you are doing an ale with a single infusion mash, etc...

It also depends on how you heat your HERMS system - is it a 110v or a 240v electric heat stick or do you have a gas powered version. The question is how fast can you move between your temp set points. Experience is your friend here - just get to know your system and run tests with plain water - that is what I did.

When I do an ale - I just use the mash temp as the set point for my HERMS system and then add my water to the mash tun which is heated from my boil keggle, gas powered heater, in around 13-15*F higher to heat the cooler then I dough in as soon as the temps have settled. Then I do a single infusion while recirculating the whole mash. I use a cooler as my mash tun so I don't really have any loss of heat - after I have heated the cooler. If you use a keggle as your mash tun you will experience some loss of heat which is now going to be fixed with your new HERMS system. To account for that you may need to adjust your temp up on the HERMS system just a bit to accommodate.

If I do a lager - I strike in a my first rest temp using the above method - let it sit for the time I want to hold it there (not using the HERMS yet) - then begin the HERMS flow with my PID set at the next step or higher temp. I have to do this because I still haven't found the problem in my 240v lines and can't use them yet - so I am bound by the 110v 5500w heat stick in my 8gal HERMS. But hey - that is me... what do you have?

Good luck and Happy Testing/Brewing in the New Year!

 

[241]

Thanks maierhof and all, very useful information.

In re: the questions, I am using a Blichmann TOP to control a Blichmann burner based on the temp in the HERMS pot, which is a 10 gal stainless Update International kettle with a 50 ft 1/2" stainless coil in it, and valves for HERMS in/out and HLT in/out via pump.

The temp ramp times seem very quick, with very little overshooting. I haven't calculated the rate yet, but generally just do ales and infusion mashes without steps so the ramp rates and such aren't a huge concern to me. What is a concern is the strike temp -> mash temp rate and mash temp -> sparge temp raise which are both reasonable as currently setup.

This is the only picture I have of the setup at the moment. It was during the first fire up with just PBW running through the system and a half filled HLT. I built a little brew stand out of that metal wire rack stuff. I'm not an engineer, so the system was designed as a "HERMS build for non-engineers" and needed to be mostly plug-n-play without elaborate wiring (I don't have access to 240) or welding. As it is, the HLT and MLT are on the wire rack which has locking casters on the bottom. I call it the mash cart. The mash cart rolls out from my garage and I bring the boiler out separately.

I plan to do a little write up with pics soon. You can see the Blichmann TOP temperature probe in a T fitting on the HLT, and the propane solenoid valve on the right, but the TOP is not pictured. I modeled the components after Kal's, just of course with off-the-shelf ready-to-purchase items from Blichmann, StainlessBrewing.com and BrewHardware.com and propane instead of electric...

 

[maierhof]

Ok - you have had a month to play - we want pics now... =;>

 

[Dcpcooks]

I built the same conceptual system but started with a 25" coil. I quickly realized I may want a larger coil. Did you make your 50' coil or did you buy it? If you have the TOP TIER gas model you want you temp sensor after your HLT as it enters your mash. You really only care about your mash temp. Your HLT temp will be higher than your mash temp but that is what we want! As you ramp your HLT TEMP will just get closer to your sparge temp, then you shut it (pump/s) down and sparge.

 

[turkeygecko]

My grain is generally about 55-70 degrees, and drops the temperature of the water by about 13 degrees, even with the HERMS. I'm sure the HERMS will 'catch up' but I strike with water about 13 degrees warmer, and then by the time I am all stirred up and break up all the doughballs (maris otter seems to make a bazillion doughballs), I'm right at mash temp and the HERMS keeps it there.

Do you then let your HLT temp fall? Unless I am brewing a big beer (above 1.070) with all sugar coming from mash, my mash temp corrects to HLT temp in about 10 minutes. If my HLT was 15 degrees higher than my mash temp, my mash temp would increase to HLT temp in about 10 minutes.

That said, I heat my HLT/strike water about 5 degrees higher than intended mash temp, transfer strike water to MLT/dough-in, start recirculating and set my HLT PID to desired mash temp, so element won't kick on until I fall below mash temp target. Then I hope my HLT temp drops to target mash temp by the time my mash reaches target temp.

 

[Yooper]

Do you then let your HLT temp fall? Unless I am brewing a big beer (above 1.070) with all sugar coming from mash, my mash temp corrects to HLT temp in about 10 minutes. If my HLT was 15 degrees higher than my mash temp, my mash temp would increase to HLT temp in about 10 minutes.

That said, I heat my HLT/strike water about 5 degrees higher than intended mash temp, transfer strike water to MLT/dough-in, start recirculating and set my HLT PID to desired mash temp, so element won't kick on until I fall below mash temp target. Then I hope my HLT temp drops to target mash temp by the time my mash reaches target temp.

I usually have to refill the HLT for my 10 gallon sized batches, at least a few gallons, and that easily drops the temperature to 156 or so and that is the temperature I want for my water in the HLT. If I'm not refilling, I just don't start recirculating until it drops.

 

[turkeygecko]

I usually have to refill the HLT for my 10 gallon sized batches, at least a few gallons, and that easily drops the temperature to 156 or so and that is the temperature I want for my water in the HLT. If I'm not refilling, I just don't start recirculating until it drops.

Ah, that makes sense

 

[cantrell00]

Due to the fact that I use my HLT to heat my MLT strike water, I dough in at my mash temp.

I had issues overheating my mash when I had my MLT (& HLT) set at +13 of target mash temp...

I have a 50' 1/2" coil in a 9 gallon HLT & my system ramps pretty quickly. I can bump 10 degrees in around 5 minutes.

My preference is to come in short of my target mash temp & let the HERMS raise it up... It is too difficult to cool it on the fly. It takes 100% of my HLT water to submerge the coil so adding a lot of cold water isn't really an option..

I don't like adding to the mash water volume because of mash pH targets etc, either.