Dedicated Herms Guide, Problems And Solution Thread

[Rieewoldt]

It's the volume of wort that is left behind after you have drained your runnings from the mash tun. The HERMS does not effect this.

Yep. I was overthinking it.

 

[Truman42]

Beersmith uses mash tun dead space to calculate your final volumes. So using herms wont matter.

 

[Rieewoldt]

Beersmith uses mash tun dead space to calculate your final volumes. So using herms wont matter.

Yep. I was thinking maybe it could have something to do with more dead space, thicker mash due to less water being in direct contact with the grain.

 

[lmccrone]

So i had the worst brew day yesterday, many problems!

It was my first go at a HERMS arrangement, my day went like this...

Fill the mash tun with water, pump it through the heat exchanger and back into the mash tun via a sparge arm ( As a side note I fond the gentle babbling of the strike water as it was pumped around very relaxing as i milled my grain.) I had programmed it to get to 55 then i'd dough in, unfortunately the brew controller blew up after 10 min, not as relaxing. As my 12 V pump was running through the controller i had to get my car battery out to keep it going, i plugged the heating element into the wall and used the temp probe from my fermenting fridge to give me a digital read on the temp of the mash water, I will be my own PID controller,.

I dough in when the water hits 55, then attempt to recirculate the mash, no good. It worked for a bout 5 min and then the flow rate of the wort dropped to about nothing (i think i can call it wort once the grain is added right?) I assume its a blockage somewhere between the pump and the sparge arm, wrong no liquid is getting out of the mash tun, its a stuck mash.

So i weigh up my options, my best bet is to cut my losses, I dump the lot into the compost. I figure i had a problem with the setting on the mill, i adjust the mill and crush another 10 kg of malt. This time I dispense with the protein rest and crank the temp up to 70 then dough in, I start the pump and this time it looks like I'm in business we are getting a good flow for about 5 mins until it all grinds to a halt again. #@#$%! Turn off the pump put a lid on the mash tun and leave it for an hour to calm down. So this time when i open the tap to collect the wort via gravity and it works fine. I then add some water to batch sparge. My problems don't end there but future issues can not be attributed to the HERMS they include hop flowers clogging up my system and cubes full of mould and pointed questions from the minister of war an finance about why i was still up at 11 pm brewing beer?

Assuming the therapy is a success and i ever venture back into the brewery can anyone help me out with why the pump would not pull the wort through the mash? FYI my grain bill was 10 kg of pils malt in about 40 L of water.

Any help would be very much appreciated

 

[dent]

What kind of pump are you running? Often if you try to pull the wort through too fast, the mash will clag up against whatever lautering screen/tube/braid/whatever and that will be that. Try to run your pump as slow as possible when you're just starting out, just enough to get the heat into the mash. Once you have an idea of how it runs, you can experiment and try to get your flow rate up faster.

If you jam it up again, get your garden hose out or whatever and push some water back up in reverse through the (switched off) pump to de-clag your system, then give it another shot.

 

[Truman42]

What is your mill gap set at? Unfortunately there is a fine line between good efficiency and a stuck mash with some of our systems.
With my system over 1mm gap I don't get a stuck mash but I do get poorer efficiency, 60-65%. Under 1mm gap I manage 70-75% but end up with a stuck mash. YMMV

Put a ball valve on your MLT inlet just before your sparge arm, ( or just past the outlet on your pump if that's easier) and when you first start to recirculate just have it cracked open a touch for 5 mins until you set your grain bed. Then slowly open it up a bit more and so on and see how you go. It may not work though (it didn't for me). So I just use rice hulls every brew and don't seem to have problems anymore.

Also try to have your brown pump mounted so the body is vertical and pointing down so the body of the pump is upper most. These pumps are notorious for getting wort in behind the impeller and seizing the pump. (Lots of threads on here about it)
It can be fixed but it's a PITA during brew day. It seems to happen more at sparge temps. Happened to me a few times and after I cleaned out the pump and remounted it, I never had the problem again.

 

[TheWiggman]

I had EXACTLY the same issue with the stuck mash. My advice is turn off off pump and HERMS, dough in, and wait 5 mins. Give the grain a chance to the clean a bit.
Close off the return valve (if you have one), turn the pump back on and open it up to a trickle ~1l/min for a bit. Then gradually open the valve 'til it's going at whatever rate you want.

If you get a stuck mash again don't give up. Turn the pump off, stir around your braid or false bottom and get the grain off it. Follow the above (choke off flow) and you should be back in business.

 

[TheWiggman]

Ed: thicken, not clean. How did autocorrect stuff that up?

 

[mofox1]

Herms... Coil in HLT Vs separate hx vessel. The latest in a long line of things I've been over thinking and/or obsessing over.

I'm not sure if I'm tying to convince myself I want a separate hx, or talk myself out of it.

I know that, theoretically, a 5500w element can heat 75L of water a degree per minute. This is assuming zero heat loss. Let's say we're very well insulated, and get close-ish to this figure.

If we have a "coil in HLT" style Herms, with 16m of 1/2" coil, we should (?) be able to assume that, given sufficient HLT water agitation, the wort coming out of the coil is virtually the same temperature as the HLT temperature (also assuming that the initial differential wasn't too large).

If you need 45L to sufficiently cover the coil and there's about 15kg or so of mass in the mash tun (60 total mass to heat), then I would assume that a 1 deg/min ramp should be achievable, since theoretically it should be able to do 75 without heat loss.

Due to pumping constraints/capabilities there would also be a couple minutes difference between the bottom of the grain bed reaching the temperature of the returned wort. Although this last point would equally affect a dedicated Herms vessel setup.

So, how much of the above sounds reasonable? Would a 5500w coil in HLT herms be able to achieve a 1 degree/min ramp for a single batch size?

 

[TheWiggman]

Sounds reasonable. Your logic is right, >1°C/min will be achievable provided there is no heat loss and assuming you initial cal is correct.
With a veeeeery long coil make sure you have a pump that can keep the liquid flowing quickly. Otherwise the liquid in the coil will reach the HLT temp quickly and you might end up with a bit of overshoot.

My personal opinion is go a separate HEx. That's not based on anything really, I just think it's the most effective approach.

 

[woodfired]

Hi guys,

I just signed up today. I'm only doing 20lt batches but my very small home made copper coil modelled off the gryphon ss coil is only about 1m long and fits directly into an off the shelf bigW kettle which I control with a pid. It achieves very good ramp times. I think this is because the coil occupies a large percentage of the space in the kettle.
All of my research prior to building indicated that maximising the amount of coil in contact with the controlled water was the most important factor in a herms. This doesn't mean lots of pipe, it means matching pipe length and coil shape to vessel. In my case a $7.50 kettle. If you get your strike water temp right, your herms doesn't have much work to do, just a small adjust after dough in. Mash out with some 80 degree water adjusted to mash ph and you only need herms to hold it there.
This has been working on my system. Interested to hear your thoughts.

WFG.

 

[dent]

I think this is because the coil occupies a large percentage of the space in the kettle.

Not really. If, for example, you took your little kettle size coil and put it in a 50L vessel which could heat just as fast as your kettle (not without a shitload of power), your ramp time would be the same. Putting even more copper in that same 50L vessel wouldn't make a significant difference.

Not that I am saying your setup is suboptimal - actually it is pretty much the same as what I run.

All that matters is that you get enough heat transfer so that the HX does not boil. This heat transfer is relative to the amount of copper (which requires very little, just like you have discovered, with only a couple kW), and the flow (which just has to be adequate). After that there are quickly diminishing returns to increasing either the flow or the amount of copper.

The only way to increase ramp rate after that, is more power.

 

[Kingy]

I've come to a couple of problem/ questions which are holding my build up.
1. The inlet at the top of the mash. What sort of configuration to run. Where to put the hole. And what fittings do you guys use. I understand you don't want any splashing or oxidizing. So do you just run a 90 degree on the outside to a weldless bulkhead (ally pot) ito a height below the liquid level on the inside or something else.
2. I had a meter length of copper laying around and tried to bend it around my template for my here unit and it bent, am I better off getting some soft copper in a coil and rebending that or is there a better way to bend copper from a straight length.
Hope this makes sence.
The bock has given me a serving. Lol

 

[Burt de Ernie]

So, how much of the above sounds reasonable? Would a 5500w coil in HLT herms be able to achieve a 1 degree/min ramp for a single batch size?

I would say without doubt however, have you given thought to what is average temp that will be maintained in the HLT? Assuming its 75 degree how would you stop overshoot?

Below is a graph showing ramp times of 40 litres of water from 16 to 67 and maintenance phase. This if from a 1.9 litres HERMS set at 75 degree.

 

[boybrewer]

I've come to a couple of problem/ questions which are holding my build up.
1. The inlet at the top of the mash. What sort of configuration to run. Where to put the hole. And what fittings do you guys use. I understand you don't want any splashing or oxidizing. So do you just run a 90 degree on the outside to a weldless bulkhead (ally pot) ito a height below the liquid level on the inside or something else.
2. I had a meter length of copper laying around and tried to bend it around my template for my here unit and it bent, am I better off getting some soft copper in a coil and rebending that or is there a better way to bend copper from a straight length.
Hope this makes sence.
The bock has given me a serving.

I just run silicone hose into the top of the grain bed no problems . If you are using a keggle you could always drill a hole in the inside rim of it and fit a weldless bulkhead into it and run some copper with a 90* elbow or just run some hose off it .

There are a number of ways to bend copper .

1. Fill it with salt .
2. Fill it with sand .
3. Fill it with water and freeze it .
4. Buy a pipe bender .

All three ways will work for bending copper without kinking it . If you buy the annealed copper from the big green shed , which is what I did . It is already coiled up , all I did was wrap it around a Milo tin to get a tighter coil which fitted snugly into my 7Lt pot all 6 and a bit meters .

 

[mofox1]

I would say without doubt however, have you given thought to what is average temp that will be maintained in the HLT? Assuming its 75 degree how would you stop overshoot?

Below is a graph showing ramp times of 40 litres of water from 16 to 67 and maintenance phase. This if from a 1.9 litres HERMS set at 75 degree.

post-26871-0-08688300-1399781793.jpg

I think the basic assumption is that you have a *lot* of coil in the tank - 15m worth. The wort temp coming out of the coil will match the HLT temp exactly (mostly, kinda, sort of). Possibly the larger thermal mass of the HLT will assist in self regulating, as it will take a proportional larger amount of input energy to cause the temp in the HLT to overshoot. I don't know... I haven't done it, or did enough thermodynamics/control systems engineering to be able to give an educated guess.

And if that fails, don't control based on the mash temp, but on the HLT temp instead. Which is probably safer anyway.

 

[Kingy]

1. The inlet at the top of the mash. What sort of configuration to run. Where to put the hole. And what fittings do you guys use. I understand you don't want any splashing or oxidizing. So do you just run a 90 degree on the outside to a weldless bulkhead (ally pot) ito a height below the liquid level on the inside or something

My concern is to not have any splashing so if I was to add bends and return the liquor at the inside of the pot the temp on the opposite side is always going to be different as wouldn't that mean I'm only recirculating one side if the mash?

Or does it not really make that much difference.

Is it easy to get the sand out of the copper once it's bent?

 

[QldKev]

Aim the return stream across the mash tun, and with enough flow the top layer will continuously mix.

This is my 3V mash tun a couple of years back. Although I'm always playing with the brew gear the return arm is still the same setup. The return is about 2min 15sec in.
https://www.youtube.com/watch?v=oIn48WUgZRU&list=UUDInzeelCPde0_pvzMdzhng


Get the soft annealed copper, it is easy to bend to shape, no sand etc needed.

 

[boybrewer]

My concern is to not have any splashing so if I was to add bends and return the liquor at the inside of the pot the temp on the opposite side is always going to be different as wouldn't that mean I'm only recirculating one side if the mash?

Or does it not really make that much difference.

Is it easy to get the sand out of the copper once it's bent?

Yeah it's easy to get sand out just flush it with the hose after tipping as much out as you can . I made a lid for my keggle and punched a hole in the center of it and poked the house down onto the grain bed where I sit it in an aluminium BBQ tray with slots in it .

 

[GrumpyPaul]

Built my Hex last night - 3m of copper in a 7 litre urn.



Ok so I started ready this and got to about page 7 and figured I would just ask questions rather than read all 61 pages.

1. Is there an ideal flow rate through the HX or does it vary dependant on factors such as thickness of mash, how hot the HEX gets etc?
I can slow mine down to about a litre/minute on a test run of just water with no grain in the MT. I have marked on the ball valve tap where to open it to so I get 1ltre/min.

2.Will the extent of the tap opening be the same if it is pumping through a the grain bed?
ie Will I need to figure out how much to open the tap in order to get the litre/min flow rate when there is grain in the MT

3. Is the slower the flow through the HX the quicker the ramp time (degree/min)?

4. Do I need to recirculate through the HX for the entire 60 min mash time?
If my mash tun holds temp well - is there any point running the pump and HX for the full time if it does need to heat the wort? Or can I just recirculate through the HEX at the end of the mash time in order to clarify the wort and to increase the temp for step mashing or mash out?