Herms Question

[KHB]

Well i tested out my new HERMS system today and i have a few questions for the folk out there who have had more experience than I. My grain bed was sitting at 65.c and my HLT was at 85.c, i started recurculating through the HERMS and noticed my HLT temp dropped to 82.c. After 10mins my grain bed had raised to 70.c. After another 3mins it hadnt raised any higher, so i stopped there. I noticed if i ran the wort through the HERMS faster it was hotter coming out. The hottest i noticed it coming out was 75.c with the HLT at 82.c. My question is does this sound about right?? How can i get it to get my grain bed up to the 75.c mark. I am using 3/8copper piping from what used to be my CFC.

Cheers KHB

 

[Thirsty Boy]

I dont get why the wort would come out hotter when it was pumped through the HLT faster... thats got me buggered.

As for the rest, I think we need a little more info on your system - what controllers you are using, where you are measuring your temps etc.

Basically, if the wort isn't hot enough to raise the temps... you have to increase the temperature of the herms vessel, in this case your HLT. You can do it manually, or via a temperature control system of some description. But it works the same anyway. The mash tun sucks heat out of the HERMS vessel via the heat exchange coil, and eventually they would equalise if you re-circulated long enough... want more heat, you need to add it to the HLT

if the wort was coming out at 75C - evetually the grain bed would have gotten there, or pretty close. Depends on where you measured your 75C.. was there a chance of heat loss between the measuring point and the Mash tun?

The other thing is what is your flow rate? say its 5L per minute, then it would take several minutes just to re-circulate the whole volume of liquid in your mash tun... its going to take a while to raise the temps, and as teh temp of the mash tun and the HLT get closer together, the rate of change is going to slow down.

Give it another burl, try measuring the temperatures in different places, try adding more heat to your HLT. Your initial ramp was good, so your system is working, its just a matter of fine tuning it till you get what you want. You HERMS is a complex way to brew, it'll take a while to work out. Just keep re-circulating, that mash bed temp will get up there eventually.

Cheers

Thirsty

 

[KHB]

I was just using a simple on off switch to control the HLT, i was measuring the temperature with a digital thermometer in the hose connected to the out post of the herms, there was only bout 30cm of hose transferring Herms to Mash tun. Not quite sure on flow rate may have been between 2 and 3 litre per minute. For some reason i could not get it flowing real fast

 

[Thirsty Boy]

Cool, I ran a HERMS as simply as that for a long time - I didn't constantly re-circulate, only used it when I wanted to make a temperature step.

What I used to do, was to switch the pump and the element in my HLT on at the same time, that way the element was adding heat at the same time that the heat-exchanger was taking it away.

I would measure the grain bed by moving around a thermometer in the mash tun, and just turn the pump etc off when I hit the right temperature. I worked well for ages, but.... without stirring the mash tun, I found that I suffered from quite a bit of overshoot if I actually waited till the mash tun thermo hit the target temp. A bit of experience and I learned how to sneak up on the target temp and get what I was aiming for.

But - that overshoot etc was why I ended up going with controllers and stuff.. its a slippery slope of technology in th eHERMS stake.

If I were to recommend a relatively simple upgrade for you that would make life simpler operationally, if not equipment wise.

I would say grab a simple on/off temp controller like a mashmate - and use it to control your HLT temperature. Then all you have to do is run through a few trial brews till you work out what the difference between the HLT and the mash tun is when they equalize. So you might have to set your HLT to say 73 to get your mash tun to sit at 67... you just have to trial and error it till you know the differential. Then its set, re-circulate constantly and walk away.

That's probably the "simplest" way to automate it a bit, not necessarily the best or the most elegant or accurate, but certainly acceptable and pretty damn easy.

Or you could do the same thing with eyeballs and an on off switch... you will still need to know the differential when the vessels equalize. So just keep on re-circulating and measure the difference between the vessels - it will depend on flow rate though, so pick one that you can achieve - say your 2-3L per minute and stick to it, you can measure it by just timing how long it takes to fill up a litre jug.

The flow rate you can get may well depend on the false bottom you are using - I was using a braid falsie for years, but I have recently changed from HERMS to RIMS and the flow rate isn't high enough for the RIMS... so I about to upgrade my system to a 12inch false bottom to increase my surface area and thus flowrate.

You need to start your re-circ nice and slowly, and build up a nice grain bed without compacting it before you try for a higher flow rate. Think about it like sparging... but all through the mash instead. If you get a "stuck" mash... it makes the whole HERMS/RIMS thing a bloody nightmare. Rice hulls are your friends and consider crushing a little more coarsely. You will lose a little efficiency from the coarser crush.. but re-circulating mash systems give you a higher efficiency anyway, and stuck mashes are a bitch.

Good luck

Thirtys

 

[Tony]

I dont use my HERMS for temperature change. I use it to holdthe mash temp at a constant temp and to clear the wort at teh same time.

If i do a temp step its an infusion or a decoction.

cheers

 

[KHB]

I have a false bottom so not to worried on stuck mashes as i havnt had one since i got it!! So are you saying you stir the mash while recurculating?? Then rest for ten minutes??

Cheers KHB

 

[Thirsty Boy]

not quite - I'm just saying that I trouble getting stable temp readings without stirring. Because you are only re-circing a few litres per minute, the top of the mash is hotter than the bottom, and when you think you have reached your target.... the mash will probably change considerably as that heat distributes itself throughout the mash.

Stirring the mash during your ramp will solve this, but it also destroys the grainbed and a fair few of the perceived benefits of using a HERMS. Not that it really matters until you are ready to sparge and you can get your grainbed back in a minute or two or re-circing at the end of the mash

I just learned that when the thermo read x during the ramp, if I stopped the ramp at that point, it would result in temp y after the mash temp had time to settle down - took a bit of trial and error.

Up to you how you manage it really, you will settle on a way that works for you in your system.

 

[KHB]

ok makes sense now :lol: I remember reading somewhere that some one said the temp of there HLT was lower below there element, mine is side mounted and i had about 6 coils of copper below the element so i have now changed that to 2. See if that makes any difference. What temp do you have your HLT at and how long does it take to get from 66.c to 75.c???

Cheers KHB

 

[Justin]

Consider agitating your HLT. You would be quite surprised just how cold that water below your element will be. Where is your HLT thermometer? You also may have a temp gradient around your coil that is lower than your measured HLT temp, thus you think your HLT is one temperature but in reality your coil and the wort inside is seeing another. If nothing it will increase the efficiency of your coil picking up heat from the HLT water.

It's good that your hose from heat exchanger to mash tun is so short, no point heating your wort up in the heat exchanger just so it can get cold again on it's way back to the mash tun. By the way, how are you delivering the wort back to the mash tun? Hopefully you have it being delivered directly under the liquid level (either a manifold or just a hose) rather than sprinkling it from the lid, that's also another way to lose a bunch of heat spraying it back through the air onto the mash.

Either way, if you're wort flow out of the heat exchanger is 75C, assuming your flow rate is high enough to counter any heat loss you are getting then the mash tun temp should rise. By the way, even with a herms it's a good idea to still insulate your mash tun.

So there are a few ideas anyway. Let us know if you have any other ideas or weird observations. By the way, i can't explain your increase in temp exiting the heat exchanger with an increase flow. It should be the opposite, unless of course you stirred the HLT when you did it.

Just some information about my system: My Heat exchanger (only about 5L volume) is controlled by an Omron on/off controller and it just heats the heat exchanger to whatever temp is needed to make sure the exiting wort temp is at my desired temp (I dont even have a thermometer on the heat exchanger). My Heat exchanger temperature probe is located on the return hose into the top of the mash tun. For me I couldn't care less what my heat exchanger temp is as long as my exiting wort is at my exact desired temp. This means any changes in flow rate wont effect the temp of the wort exiting the heat exchanger as it will heat or turn off according to the wort temp. Takes all the guess work out IMO.

Just some thoughts, Justin

 

[KHB]

ok i may lenghthen my hose as the wort was returning from the top of the mash tun via the wall, the thermometer is i little bit above the height of the element bout 10cms. Sounds like i need some kind of tempretaure controller, will look into a temp mate when im more cashed up.


Cheers KHB

 

[Justin]

A longer hose may improve your set up IMO, but your current set shouldn't be too bad and it's not the source of your problem. It's more the sprinkling type that loses the most heat. Each droplet has a large surface area to volume ratio so sheds heat quite quickly. Your set up sounds ok though.

You dont necessarily need a temp controller, just make sure you stir your HLT well to get an accurate reading and an even temperature. The reason you dont need a temp controller is if you are using your HLT as your heat exchanger then there is so much water in there that the temp is not going to change up or down very quickly at all. Even with a temp controller it wont fix the temperature stratification in your vessel and the problem will remain, you need to agitate the liquid. It sounds to me like your thermometer in your HLT is reading the hot water rising up from the element giving a false, elevated reading of what the actually temp of your vessel is. Next time you brew, stir regularly and see how it goes. I wonder if your HLT temp was actually only 75C, not the 82 you think it was.

It's a possibility, but having your temp guage directly above your heating element is not really the best place for it unless you stir your vessel well.

Cheers and good luck. Justin

 

[KHB]

Well ill be brewing Wednesday so i am going to try and lenghten my hose and stir my HLT. Will report back my findings.

Cheers KHB

 

[Thirsty Boy]

good luck with it KHB - justin's given you some great tips there - if you do go for the temp controller at some stage though... I would be putting it in your HLT (the stirring of which would be a great thing..)

Not saying that Justin is wrong with his placement of the temp probe at the point of wort return to the mash tun... in fact thats exactly how I think it should be done and how my rims is set-up.... but, I think that with your coil in the HLT rather than a separate HERMS vessel, that opens you up to a bit of overshoot. Once the controller has heated your whole HLT up to the temp where the wort starts coming out at your target temp... there is now enough heat in the vessel to push the output temp even higher. This would be much less sever or possibly not a problem with a stirred HLT, but would give you curry with a non stirred vessel. Whereas, with the probe in the HLT... if its fixed, you can still do a calculation to work out the differential between the probe reading temp and the wort exit temp... one that should stay fairly consistent with a "standard" amount of water in the HLT and a constant flow rate.

There are unfortunately stacks of different ways to make it work... each one with its good and bad points. How to set up a HERMS/RIMS is one of those questions that will get you 15 different answers from only 10 different brewers. On the bright side... there are stacks of ways to make it work, so you are sure to find one that fits the bill for your situation.

You will make it work for you, you just need to play with it till you get it going the way you want.

Cheers

TB

 

[SpillsMostOfIt]

:icon_offtopic:

How to set up a HERMS/RIMS is one of those questions that will get you 15 different answers from only 10 different brewers.

Agreed. It is one of the less contentious discussion topics... :lol:

 

[Justin]

good luck with it KHB - justin's given you some great tips there - if you do go for the temp controller at some stage though... I would be putting it in your HLT (the stirring of which would be a great thing..)

Not saying that Justin is wrong with his placement of the temp probe at the point of wort return to the mash tun... in fact thats exactly how I think it should be done and how my rims is set-up.... but, I think that with your coil in the HLT rather than a separate HERMS vessel, that opens you up to a bit of overshoot. Once the controller has heated your whole HLT up to the temp where the wort starts coming out at your target temp... there is now enough heat in the vessel to push the output temp even higher. This would be much less sever or possibly not a problem with a stirred HLT, but would give you curry with a non stirred vessel. Whereas, with the probe in the HLT... if its fixed, you can still do a calculation to work out the differential between the probe reading temp and the wort exit temp... one that should stay fairly consistent with a "standard" amount of water in the HLT and a constant flow rate.

There are unfortunately stacks of different ways to make it work... each one with its good and bad points. How to set up a HERMS/RIMS is one of those questions that will get you 15 different answers from only 10 different brewers. On the bright side... there are stacks of ways to make it work, so you are sure to find one that fits the bill for your situation.

You will make it work for you, you just need to play with it till you get it going the way you want.

Cheers

TB

You are certainly right Thirsty, I was making specific reference to my set up that utilizes a very small seperate heat exchanger that is independent of the HLT. In reality my setup functions more closely to a RIMS setup than a true herms, and probably takes advantage of the best points of both systems. My heat exchanger only has a volume of around 5L, it is agitated and contains an electic element coupled to a temp controller. In this set up I have the temp probe for that element located in the outflow from the heat exchanger, so I have little care for what the heat exchanger water temp is as long as my wort is exiting at the desired temp. This little unit is quick to respond to any temp demand required by the temp probe and works brilliantly, even with quite a high flow rate. It self regulates for changes in flow rate and in my opinion is the ideal set up. But like always we all have our opinions and can choose to do it however we like, many different ways work. I just chose this way. In the end we still all make beer and do what works for us.

My HLT is also temp controlled but from a seperate temp controller. It's not linked to the HERMS side of things at all. But thanks for pointing out the difference, I agree with your point and realise I may not have made it clear. I still think agitation is a good thing if you have a temp controller or a mounted thermometer if you want accurate readings, especially if you are running your HERMS through it also. FWIW when my HLT is heating up my strike water I run my march pump to serve as the agitation to mix the water.

Cheers, Justin

 

[Thirsty Boy]

I like the sound of your system Justin, seems like the ideal way to remove some of the issues I see with a HERMs, without introducing the issues you get with a RIMS... nice.

TB

 

[KHB]

Adding to this does anyone in adelaide have a system similar to mine who would be willing to have me round for a brewday to demonstrate how theres works??

Cheers KHB

 

[KHB]

Well i brewed again today i did it the same way only changing two things.
1: I agitated the water in my HLT which dropped the temp 2.c
2: I used a longer hose which just sat in the grain bed.

I probably had the same success as last time raising 5.c over 10mins but still not enough i noticed that my wort was coming out at 78.c so a bit warmer this time.

Next time will probably try a sparge arm so the water is getting spread even on top of the mash and not in one central spot. I know i will get it eventually just not ready for a 3 step mash yet!!

Cheers KHB

 

[Thirsty Boy]

If the wort is coming out at 78... it HAS to heat up eventually. Where can all the heat be going??

Where/how are you measuring your mash temp? ... just searching now - the answer will be something simple for sure

 

[KHB]

I have a mashmaster thermometer in the side of the tun which would have been in the middle of the mash, and a hand held thermometer i was using in the top in different spots