Herms build advice

[Lockwood16]

I would very much welcome your advice on a proposed budget HERMS build. I have tried to get up to speed before posting, but appologise for any dumb questions I may ask!

My system currently is a single S/S vessel used for heating mash water and boiling wort. I have a Colemans 33L coolbox serving as a mash tun.

I realise that I am putting the cart before the horse, and should wait and save up to purchase a nice shiny thermopot complete with taps screens etc, but having spent a bit on building my control panel etc, I will have to put that on hold for now.

I have cracked water and wort control with PID's, and fermentation control with STC and fridge, so now looking to improve consistancy on my mash temperatures.

I have just purchased a 4.5L S/S pot and intend to fit a 2.4Kw kettle element and coil and need another PID, SSR etc to control it, and have some questions on the actual mechanics of the HERMS.

1. Is there an optimum coil length ? I can get around 8or 9 coils of 5 inch diameter in my pot

2. I would love a S/S coil, but I understand they can be difficult to bend properly, apart from the aesthetics, is there another reason for going all stainless? as the heat transfer is poor compared to copper.

3. Can anybody recommend a pump and ways to control this, (ie,12V or 24V,) suitable for small 23 L brews,

4. Does the return from the pump to the mash tun need some sort of sparging arm to distribute the water over the grain evenly?

5. Best way to minimise stuck pipes etc when running HERMS, (I presume it would be best fitting the pump below the level of the mash tun for this?)

6. I am currently jugging in the required amount of mash water into coobox, what is needed to use the pump for this purpose?

7. Once the temp from the exit of the heat exchanger is up to mash temp, is that the time to set timer for mashing?

8. Best way to fit a sensor to a 3 way tee pipe for monitoring exit temperature of mash water

Sorry for long post. There may be other potential problems I have not thought through yet, therefore any advice you can offer would be very much appreciated, especially help on what kit you used for pumps, controls etc

Best regards, and look forward to your help and replies,
Lockwood 16

[fego]

This might help...

viewtopic.php?f=60&t=65732

[och29]

I have a fully stainless HERMS so:
1. / 2. Stainless does have relatively poor heat transfer compared to copper but copper dissolves in acidic solutions such as wort so I and many others don't use copper in our kit. You can buy pre-coiled stainless tube as an immersion wort chiller.
3. I use a 24V pump for 60L batches
4. I get best results if you use a thinner mash (more water) so that there is a good layer of liquid on top of the grain. I then had a section of tube with holes drilled in the sides as the output on top of the grain. Cheaper than a sparge arm and reduces oxidation of the hot wort.
5. Most pumps don't self prime i.e. won't pump air so have to be below the level of the mash tun. Prime the pump by letting gravity take its course then switch on.
6. You can use a process called under letting where you add the grain to the mash tun and pump water in through the outlet at the bottom. If done slowly then you shouldn't get any doughballs and is a brilliant way of adding strike water. You'll need an outlet on your HLT, one on your mash tun and two hoses to connect (NB you'll need an extra one when using the HERMS pot).

[och29]

7. That's what I do
8. Use a three way Tee, have the output of the HERMS and the sensor in the two opposing sides, put the connector that will take the wort back to the mash tun on the other side... so it comes out at a right angle. This prevents clearance issues with the probe and the tee. Connect that to PID to control the relay for the element.

[Lockwood16]

Thank you och29 and fego for your replies, they were indeed helpful.

I have some additional questions you may be able to help me with prior to plunging in and purchasing gear.

1. Do you monitor the temperature exiting the mash tun alongside the exit of the HERMS?

2. Are you able to expand a little on whether you control the flow of the mash fluids either by manual valve control or by controlling the speed of the pump

3. If you are using electronic pump control on either solar or mag pumps, what type, ie a PWM controller etc etc? if so can you point me in the direction of such?

4. Are you using a simple compression type fitting on the tee piece to hold the PT100 sensor in place?

5. Again, are you using the standard PT100 sensors from the usual suppliers ie Mr Lard, Angel home brew? or using the cheaper ones from ebay?

Best regards,
Lockwood16

[och29]

Yes, PID control is taken from HERMS out
I use a valve - all my pots have a valve attached to an input near the top and I have mag coupled pumps... works well for me and if I upgrade the pumps to a different voltage it will still work
.
Compression to threaded fittings on the coil the threaded tee
Yes, using the 30mm temp probe from MrLard

[Lockwood16]

Thank you so much for your reply, och29, it is very much appreciated.

I can now proceed in making this HERMS with much more confidence.

Best regards,
Lockwood16

[och29]

No worries, if you have any more questions I'd be happy to help.

[Lockwood16]

Whilst waiting for the bits to arrive, I was thinking about using the seperate HERMS and batch sparging, and how it would work together.

My current proceedure is, mash for 90 minutes, then (using Beersmith, and sparging with equal volumes) I add x amount of water, stir, wait a few minutes and then after vorlauf to ensure wort is clear, I then drain and measure batch 1.

I then repeat with xx amount of water, repeat as before, giving me a target pre boil volume made up of two equal amounts of sparge water.

Now from what I understand of HERMS, it is supposed to give you a much clearer wort after recirculating, for 90 minutes.

Question: After the 90 minutes is up, what happens then? If I follow my previous proceedure, and add the first sparge water and stir, I will have ruined the entire 90 mins recirculation, and end up no better than before, ie not entirely clear wort.

So, after the 90 mins are up, do I then drain the mash wort first? then add the first addition of sparge water and proceed as before? Or do you recirculate both additions of sparge water before draining each one to ensure the wort is clear?

I appreciate that the primary purpose of HERMS is to ensure a constant mash temperature.

Any advice would be very much appreciated.

Best regards,
Lockwood16

[och29]

I've only fly sparged... is it out of the question for you? You could still recirc in between transfers to the kettle, I believe waiting helps increase efficiency. Otherwise I'm not sure how post mash clarity will affect beer clarity. There is a lot that happens in the boil and FV that changed clarity.

[Lockwood16]

Hi och29, I could if I had to. It's just that batch sparging works for me at present. I was thinking of perhaps draining off the wort after 90 mins to the boiler, then adding the required amounts of sparge water, and just giving it a quick stir to get the sugars going and then recirculate until clear, and then drain to the boiler.

Does this sound reasonable?

Best regards,

Lockwood16

[sladeywadey]

What you could do is use as much mash water as you can get in the mash tun for mashing (Kind of like BIAB). Then, herms as normal for 60-90 mins. Then, turn the PID up to 76C (takes 7 minutes for a full system temp rise on my rig). Then, after a further 10 minutes recirculating at the 76C temp, drain half out (or the minimum amount necessary so you can fit the rest of the sparge water in). Put the drained wort into boiler. Put the rest of the preheated sparge water in to the tun at 76C, a quick stir and recirc via herms for 10 minutes or until clear again. Then run the rest off to the boiler and boil away.

That's the method that I have moved to recently. I get very clear wort into the boiler now with about 75% efficiency.

[Lockwood16]

Thanks for all your advice, it is very much appreciated. I now look forward to the parts coming and the build too.

Best regards,
Lockwood16

[sladeywadey]

Super no probs - keep us updated on the build and operation. I love my HERMS set up and will be trying to do step temp mashes again soon. Just a quick point - I use a copper HE in a small 5 litre bucket. Works fine but you do need to ensure the inside of the coil is cleaned after each use etc.

[Lockwood16]

Sladeywadey, did you use 10mm copper tubing for your heat exchanger?

I have purchased a 4.5L stainless steel pot ready for the fitting of a 2.4Kw heater. Undecided whether to fit coils coming from the pot lid, or fit these from the side.

I decided against fitting the 2.4Kw element on the bottom of the pot, instead I will fit this on the side, as low as it will fit, so the pot will be stand alone.

I have purchased a low cost PID controller complete with PT100. I was wondering what fittings you used to fit the PT100 into the "T" piece. The PT100 supplied is 5mm, so I guess I need a 5mm to 1/2" reducer, failing that, 5mm to 1/4", then 1/4" to 1/2".

Any other advice would be most welcome.

Best regards,

Lockwood16