Dedicated Herms Guide, Problems And Solution Thread

[TheWiggman]

Not a derail at all, I think it's critical to know what's going on and is an issue unique to HERMS. For instance, I've been having stuck sparge issues recently (turns out my braid was blocked with filth) which has been limiting pumping rate. Result was a sloooooow step change in the MT and thus high attenuation on a handful of recipes.
I now have the recirc tap opened 100% following initially settling of the mash bed and don't touch it.

 

[fraser_john]

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.

Yup, this is what happens.

Have to note that each HERMS configuration is different and it will take time and experimentation on your own HERMS system to find out what step temperatures and times result in the attenuation you are seeking.

I have two programs for Ales, two programs for Pils and one Weizen program in my Ramp/Soak PID. For the Ale/Pils, one of the programs results in a drier (well attenuated) beer, the other a sweeter beer.

I typically just use the drier program and add more crystal to each recipe as required.

 

[Tahoose]

Have had an idea for my Hi-Flow HERMs theory, it's basically a HLT/MT/HX.

Thinking big batch size here so for arguemets sake lets say that it's a 100ltr pot nested inside a 150 litre pot.

The mash pot is the inner pot and containes; a domed false bottom, a threaded pipe wort overflow return and an outlet which drains to the pump. This sits off the base of the outside pot by 100mm.

The outside pot holds the inner pot, and the coil/wort return. It also has an element and a drain to the pump.

The theory is simple:

The mash drains and re-circulates through the pump and up the coil back into the top of the mash. The flow is high so whatever doesn't drain through the mash finds the point of least resistance being the "wort overflow return".

The element is controlled by either an stc-1000 or pid and heats a body of water that sits around the inner pot, this acts as a water jacket and heats the coil.

At the end of the mash out the the wort will be drained to the brew kettle, the element switched off and the body of water in between the pots will become the sparge water, initial thought is batch sparge with a 10min recirculation.

The mash will re-circulate of it's own accord and with a loose water to grain ratio stuck sparges will not happen. By design you're not expecting all of the of the wort to flow through the grain bed anyway. Different sized batches will be determined by the length of the wort overflow return.

I anticipate that the HERMs crowd might say that the body of water is too much to heat up the coil properly. However think of it more as heating up the HLT full of sparge water rather than a dedicated HX.

Because of the amount of space taken up by the inner pot I'm not sure what sort of volume the sparge water would be but I'm taking a punt at 20-25% of the total volume.

So without a seperate HLT to sparge from this is looking more like a BIAB mash with a mini sparge.

Credit for inspiration see this thread.
http://aussiehomebrewer.com/topic/83760-adding-recirculation-my-easy-urn-upgrade/#entry1240432

 

[Tahoose]

Sketch relating to previous post

 

[Kingy]

I was wondering before I drill the holes in my hex. if the inlet and outlet of the unit are both at the top (inlet top left, outlet top right) does all the liquid after brewing still drain out with the gravity if I was to drain at the lowest point of the pump. Or am i to try get the inlet at the bottom left and the outlet at the top right.
I think the latter is achievable but gunna be hard to get the copper to not touch the element or is that not a problem?

 

[TheWiggman]

Kingy, no not all the water will drain. For the most part it will (as having the pump below the coil will act like a siphon) but when the air begins to work up the pipe/coil under the water, some water will fall and thus air will bubble up. The liquid that falls will settle.

 

[Tahoose]

Well HERMs setup is halfway built. Won't be in a permanent position for a couple more months but should see a HERMs brew this week (fingers crossed)

 

[j-dunn]

Hi All.
I currently do BIAB. I have a 60 lt boil kettle with a basket for the bag. Simple and works a treat. I have about 20 brews down and most have been great.

I am wanting to make a HERMS using a 30lt Urn with an 18 mt coil in it. I have a temp control that I was going to have the probe in the mash tun.

Is a 30 lt HLT with the coil in it ok for the 60 lt MT and 60LT boiler? I will have a gas fired boil kettle .
cheers
Joe

 

[razz]

I had a 14 mt coil in a 40lt HLT Joe and that worked just fine. 18mtrs will be plenty, what size is the element?
With the placement of the probe in the mash tun, you will find that at the outlet of the herms return is a popular location.

 

[TheWiggman]

Are you looking at the best option or do you have the gear already? If you have the gear then yes it will work, but I wouldn't use all 18m nor all 30 litres. It'd be more efficient as a standalone HERMS if you only had 3m of copper in the bottom and only filled enough water to cover it.

 

[j-dunn]

Awesome Guys, thanks for the replies.

I do have the 30lt urn, 2000w element,actually the base of my "water purification plant", an amazing device that makes 90% Alch!

I also have the 2 x 60 lt pots for the boil kettle and mash tun.

Using less coil sounds the go!

Another question I had was will the recirculating mash and sparge water coming into the mash tun while at mash temperature effect the beer, ie hot and being oxygenated?

Cheers Again!

 

[razz]

Re the liquors coming in hot and potentially adding O2, plenty of talk on here about it over the years. Lots of brewers splashing back into the mash tun and still make great beer. If you want to, make sure the return has a piece of silicon hose on it so the liquor coming back into the mash can mix without splashing.

 

[CanMan]

Seems that the best place to monitor temperature is at the return to the mash tun. I am interested to know if the wort gets slightly hotter before if reaches the return is it going to effect the wort. From a scientific perspective when talking about a certain mash temperature is the temperature circulating over the grain what is required or the temperature the wort reaches at an given point in a system during the mash process.?

 

[Yob]

Measure at the HEX outlet, this is where the critical temperature is. Easiest point to measure also...

 

[Mardoo]

In designing a HEX is it important to have the copper coil surrounded on both sides by the HEX water? Seems like it should be.

I'm working with a 3L HEX vessel and I can jam in more copper coil if I push it all the way out to the sides of the vessel. The vessel will be well insulated so heat loss to outside will be dramatically reduced. Logic and Adr_0's PID Modelling thread seem to say more coil good, less coil bad. But if by and large only one side of the coil is exposed to much thermal mass within the vessel it seems like ramp times could suffer.

If I went with the copper coil pushed out to the sides of the vessel would a higher flow rate offset the difference? But then, if I'm having to offset what's the point?

Me brain be tellin' me shorter copper coil fully surrounded by the HEX water. What says the hive mind? This is my first HEX so I don't have any experience to back it up. Max batch size will be 45 litres, 2400w element, copper coil, 3 litre HEX volume.

 

[MartinOC]

In general, a smaller HEX vessel will give better "response" to the brewer's requests for changes in temperature (up or down). The more copper you have in that small vessel the better.

If you're insulating the HEX, then the fact that the coils are touching the sides shouldn't make much difference (within a poofteenth of SFA, since copper is a great conductor & will transfer it's incoming heat to the full circumference of the coil in about 12.6th of a Femtosecond*).

Conclusion: Just build it, brew with it & learn your system around it.

* Femtosecond = The time taken for a beam of light to cover 1 metre.....

 

[Adr_0]

Well, your area won't be cut in half but it will be cut down a bit, so I would try to keep it off the sides. Apparently you can fill your coil with sand and then you can hopefully get a tighter bending radius. If you can find a smaller bit of pipe this might help?

What sort of lengths are we talking here?

 

[trevgale]

I have a 2L HEX with about 2m of 1/2" stainless coil and a 3000W element, there is about 5mm clearance at the outside although other than being easier to remove I don't think the clearance would do much for performance as the enclosure is likely to be a similar temp. My HEX works well so I would expect your proposed system should be fine given the extra coil length and copper being a better conductor than stainless.

 

[Screwtop]

Seems that the best place to monitor temperature is at the return to the mash tun. I am interested to know if the wort gets slightly hotter before if reaches the return is it going to effect the wort. From a scientific perspective when talking about a certain mash temperature is the temperature circulating over the grain what is required or the temperature the wort reaches at an given point in a system during the mash process.?

Measure at the HEX outlet, this is where the critical temperature is. Easiest point to measure also...

As Yob says the place to measure is at the hottest point in the closed system. HEX Wort out is that point, wort temp will not be higher anywhere else in the system. No point measuring in the Mash Tun if the wort temp is going to be higher somewhere else in the system. After you have been using your HERMS brewery for a while you will be able to dial in fermentability, maybe not according to traditional mash tun temps, but the temps which provide a certain body in 'your' beers using your system. Step mashes are also a cinch!

Screwy

 

[Adr_0]

The system will make delicious beer at some point regardless of how long the coil is, how powerful the element and how big the HEX is.

There is a lot to be said for understanding a few things and how they might influence time, ease of use, flexibility and predictability. It's not worth getting to the last 1% but if you're a few hundred % out to begin with it might be worth making that adjustment - if you understand why it's important, and that is important to you. A bit of thought in this stage can hopefully give you time when you're brewing, but don't do your head in thinking about it.