Dedicated Herms Guide, Problems And Solution Thread

[Mr B]

I wasnt interested in this hobby when I thought it was mixing a can of goop with water to make standard tasting beer with a nasty homebrew twang.

Then I found out about pumps, stainless, chemistry, recipes, timing, yeast, cleaning, sanitisation, gas burners, build design, brewrig options and much more.

Now I'm hooked.

And have made some mighty fine beers, peer reviewed as 'holy fark', and 'just thought i'd drop in'.

But I just BIAB so far.

And its all good, simple or complex.

(I'm going to herms soon, planning, planning..........)

 

[Tahoose]

Ok guys have read half of this thread but need to ask this before my mind gets ahead of me.

I'm basically looking to looking to move to a 150ltr brew system.
The only things I don't have are;
copper coil
Pump
Couple of camlocks

Now my biggest query is, how big should my coil be for a 25kg grain bill? Most of the info in this thread is saying 3m is a good length. But I'm thinking that given the size I'm going to need a bit more.

 

[QldKev]

I think the coil length will need to be in relation to the heating potential of the elements required. For a 150L brew (is that final vol?) you will need more than 2400w in the HERMS. So my guess would be a min of 4800w and 5m of coil. But the HERM-IT coil is only 3m, and being stainless has no where as good as a heat transfer coefficient as copper, people run 3,000w in them. Maybe with copper you could get away with 3m and 4800w?

edit.
Actually I was thinking of my sized system with 4800w. 4800w on your system would be more 0.5c per min.

 

[mofox1]

Double the tube length, double the power... Does that mean also double the flow rate? Always wanted a reason for a centre inlet chugger!

Good thing I'm only doing up to 70's with my crappy little kaixin's!

 

[Yob]

Always wanted a reason for a centre inlet chugger!

keep in mind the centre inlets head also fit March pumps... and also...

you have plenty of reasons in that shed of yours... :super:

 

[TheWiggman]

Agree in principle with QldKev. Considering most do 23l batches and use a Chugger or Kaxian, I'd imagine to maintain the same performance you would need to scale up accordingly - by a factor of 5. That is if you want to do step mashing at a rate of 1°C/min.

Two things matter here in this order - amount of heat/energy input and conversely flow rate.
Upping the energy is all well and good but if you have a low flow you will apply a lot of heat to the wort in the coil, and won't be transferring much energy into the mash. You need lots of flow AND heat input to raise the temp of the mash bed.

If you don't want custom pumps this can be acheived by running a number of pumps in parallel with a few HERMS coils in parallel. Or, go a larger diameter single HERMS coils (i.e 3/4" instead of 1/2") and make it longer to accomodate for the reduced transfer efficiency of the larger diameter. Then plumb the parallel pumps into the one coil.

Gut feel tells me a minimim of 3 x March 809 pumps and 5m of 3/4" pipe, with 6000W of heat power.
Might seem excessive but you are increasing the mash volume by a factor of 5 compared to single batches. If I were you I would go a single March 821 or similar running at the 45l/min mark. In reality it will do less than this due to pipe restictions but will be much easier to manage than a few individual pumps.

 

[QldKev]

I run a 112L batch (beer output) on my 3V. With a 2000w HERMS and 2400w Internal RIMS I can get just under 1c per min. That's just running a single standard March 809 with all valves fully open. Pushing that to 150L would be probably down to 0.5c per min.

 

[TheWiggman]

How far does the mash bed follow behind? i.e. difference between HERMS out and mash bed once target temp is hit at the HERMS.

 

[Tahoose]

Yes it will be 150ltrs post boil. I'm not concerned too much about if I get 1c/minute or .05c...

The system I have in mind is a longer coil and I plan to have a hi-flow rate. Will have a bypass return so the wort that doesn't filter through the grain bed will pass down straight back to the bottom of the manifold. In theory (in my head anyway), this along with a loose mash will not cause any grain bed compaction.

The 2 things that I look to gain from the system are semi automation and better control over stepping up temperature rests. Also it will be a fire and forget system. It has fails safes in mind so you can mash in and walk away. I also have long mashes mind, maybe overnight like some of the braumiester guys do.

Maybe I'm living in my own little brewing dream world?? Hahaha

I'm hearby coining the term "Hi-Flow HERMs"

The full build won't be for a about 4 months (move into the new place) but I'll be thinking and tinkering until then.

 

[QldKev]

How far does the mash bed follow behind? i.e. difference between HERMS out and mash bed once target temp is hit at the HERMS.

I've only tested the HERMS outlet vs the bottom of the mash bad under the false bottom. On a 10c ramp I've seen up to 7c difference, but within 5mins or so it balances out.

 

[Mardoo]

So would there be an advantage to going by mash bed temperature for timing mash steps? It seems like that would make sense since the grain is what you want to convert. Brain hurt now.

 

[Kingy]

after reading the last few posts. if i was looking to end up with 66 litres into fermenter at end of brewing. A 5mt copper coil in an 8litre capacity unit with 2400watts would be better than a short stainless herm-it (nev ) in a pvc cylinder (2400watts also)

 

[Cocko]

So would there be an advantage to going by mash bed temperature for timing mash steps? It seems like that would make sense since the grain is what you want to convert. Brain hurt now.

I wouldn't think so, being it is the 'lagging' temp - best take the reading at the hottest point is what I have learnedid and seems to produce the beers to the desired result.

It is not the physical 'grain that is converting but the enzyme activity, as far as I understand, this can happen in liquid too....

May be WAY off here but my understanding.

 

[MartinOC]

So would there be an advantage to going by mash bed temperature for timing mash steps? It seems like that would make sense since the grain is what you want to convert. Brain hurt now.

Dear Mr Gumby (sorry, I just got the Almost Complete Monty Python collection for my birthday)..

The sugars & enzymes go into solution & get recirculated. The important temperature to monitor is at the exit of the HERMS coil (ie. the hottest point). The grain bed is inert & just provides the filter-bed & a thermal mass that buffers rapid temperature fluctuations.

Edit: Beaten to the punch by Cocko. "Sorry! I had my head stuck in the cupboard!"

 

[TheWiggman]

This thread is bloody massive now but I recall discussions about this issue earlier on. Here's my take now that I've done some reading and have more of an understanding of things. I think.
The starch from your grain goes into solution and is converted to sugars within the solution. The temperature of the solution is what matters.
If you want to heat the mash (referring to liquid, not grains) then ideally you want it to be changed instantaneously. You could do this by taking a portion of the mash, heating it above your mash temp, then putting it back in the mash a la decoction. However this will push a portion of your starch well above sacc temps and cease conversion for that portion, assuming it got above 76°C.
With HERMS you are heating the solution slowly hen trickling back into the pot. You don't want the temp to exceed your rest temp else you're converting above your desired temp. With a slow flow rate the mash tun temp will lag and will slowly convert in the mash at temps lower than desired. If this took long enough you should expect higher alpha amylase conversion than desired limiting the available starch for conversion at your target temp.
Now I'm no brew guru but my research thus far lines up with that. I would personally favour a faster ramp than a slower one because ideally I think you'll have more control of step mashing.

 

[Cocko]

This thread is bloody massive now but I recall discussions about this issue earlier on. Here's my take now that I've done some reading and have more of an understanding of things. I think.
The starch from your grain goes into solution and is converted to sugars within the solution. The temperature of the solution is what matters.
If you want to heat the mash (referring to liquid, not grains) then ideally you want it to be changed instantaneously. You could do this by taking a portion of the mash, heating it above your mash temp, then putting it back in the mash a la decoction. However this will push a portion of your starch well above sacc temps and cease conversion for that portion, assuming it got above 76°C.
With HERMS you are heating the solution slowly hen trickling back into the pot. You don't want the temp to exceed your rest temp else you're converting above your desired temp. With a slow flow rate the mash tun temp will lag and will slowly convert in the mash at temps lower than desired. If this took long enough you should expect higher alpha amylase conversion than desired limiting the available starch for conversion at your target temp.
Now I'm no brew guru but my research thus far lines up with that. I would personally favour a faster ramp than a slower one because ideally I think you'll have more control of step mashing.

These are the exact words I would have used if I could use speaking n stuff...... ^^^ Well said Wiggers.

h34r:

 

[MartinOC]

Nailed it!

 

[stux]

Which leads me to suspect that like how BIAB has trouble scaling, HERMs might too, but for different reasons

There's gotta be a reason big breweries use heated mash tuns (steam jackets)

 

[MastersBrewery]

Which leads me to suspect that like how BIAB has trouble scaling, HERMs might too, but for different reasons

There's gotta be a reason big breweries use heated mash tuns (steam jackets)

Actually a lot more use direct steam injection, which is an instant kick in heat with no chance of scorching (big reason for choosing herms) and with little actual water added to the mash. I have seen this done on a home brewing scale with a preasure cooker. Thinking about stepping larger batches, using herms and direct steam together could be the easier solution.

MB
Ed: With larger batches, the grain bed lags exponentially, even with increases in flow and heating I don't feel you'd keep up. Whilst thining the mash and proper procedures in setting the grain will mitigate stuck mashes, your pushing limits.

 

[Mardoo]

So then all that's happening in the grain bed is liquification of the starches and all the enzyme activity happens in the mashing liquor? That makes sense considering that the grain:water ratio affects enzyme efficiency.

Sorry for the derail, the differential in liquor and grain bed temperature just never occurred to me before since I'm only in the process of setting up my first HERMS. Thanks for the help guys.