Mashing temperature, PID tuning, and wort circulation.

This is about my recently finding and thought about mashing temperature measure and control in recirculated E-BIAB.

Here is two typical designs of recirculated E-BIAB kettles. The main difference between them is the direction of wort circulation.

A. Top-down, eg. Grainfather.

kettle_topdown

B. Bottom-up. eg. Braumeister

kettle_bottomup

I don’t have any experience with Braumeister or the like. My issues are about the design of Grainfather. My conclusion is that Braumeister might have a better design, and if you are going to build your own brew kettle, go with design B, the bottom-up method.

The issue wasn’t clear to me until I drew the picture: the design of Grainfather creates 3 zones of wort/mash.

When the wort drains down, a compact grain bed will be formed, which results in slow draining from middle part to the bottom. If the mash is mixed well when doughing in and the heat didn’t lose too much, it might be fine. However, it is a different story when multiple rest steps are needed because

the main sensor and the heater are at the bottom and the flow from middle part to bottom part is slow. The result is slow temperature ramp of the mash in the middle.

Conducting thin mash or add rice husks can speed up the wort draining but result in fast sparge.

The temperature of top portion can be risen quickly if the flow of wort is quick and drains through the overflow pipe.

I have been wondering why the PID parameters tuned with 2 gallon water worked “better” than that with 4.5 gallon water. Now it’s all clear to me: the PID was effectively controlling sound 2 gallon of wort.

Here are some charts. FYI.

I forget to switch the heater to “mash” position. The PID was tuned with 4(or 4.5) gallons of water.

whole

The heater was switched to “mash” position. The PID was tuned with 4 gallons of water (same as above.)

mash-2

The PID parameters were derived from tuning with 2 gallons of water.

gfbrew

 

24 thoughts on “Mashing temperature, PID tuning, and wort circulation.

  1. Sounds interesting. You have to measure the tempurature in the middle of the grain bed to be sure. Were you able to do that.
    What will be the effect when you stop/pause the circulation every 10min for 60 seconds or so?

  2. There are downsides with both systems… but the thing you take up is the downside with the Top-down…
    The downsides with the bottom up, is that as soon as you raise the mash basket, the wort instantly gets alot more cloudy – since everything drops to bottom.

    Also, one problem with the Braumeisters is that they have very limited malt capacity – and when people have over-topped the limit (6kg to BM20) the pumps have burned out.. But as a whole, the Braumeisters is alot better quality than Grainfather – but again, they cost pretty much twice as much – so that is expected.

    Many people have been using BIAB mesh baskets (mesh sides instead of solid sides) and they never seem to have trouble with stuck mashes, and temperature is also more solid – since the wort that doesnt go down through the bed – escapes through the sides and keeps the mash in temp from outside, better than when it goes through the center-pipe of the GF.

    I run a kettle and solid sided basket, but i’m right now looking at changing to a mesh-sided basket… also we have possiblity of going finer mesh on the sides than the bottom!

  3. Dear Vito, sincere apologies for writing you on another subject. You know because the shipment has been changing since February 2. The number trackig is LK008597765US.

    “February 2, 2017 , 8:15 am
    Departed USPS Facility
    MIAMI, FL 33112 “

  4. Because of no ability to drill a hole of the top screen, I have to remove the top screen to measure the middle part.
    Another issue might rise: how high the temperature will go to heat the middle part to desired temperature?

    The real issue is caused by the “compact grain bed” which causes slow drain and hence slow rising of temperature.
    I don’t see stop the pump will help. Instead, I suspect it should be worse.

  5. I don’t have any experience with Braumeister or any bottom-ups.
    There might be down sides of it, but I guess that Braumeister should do better in this case.

    I preferred solid side basket over mesh because grain bed can be formed and fly sparge is possible.
    (The solid side basket is like a general mash tun, so I think fly sparge is possible.)
    Grain bed should help to produce clearer wort.
    Fly sparge helps in sparge efficiency.

    This root cause of this issue,uneven temperature or temperature slow rising, is the grain bed.

    There is no perfect solution.

  6. WRT: “Because of no ability to drill a hole of the top screen, I have to remove the top screen to measure the middle part.”
    Why not just remove the silicon bead on the o/s. You should be able to get a cable down the side then.

  7. I am thinking about that, but that seems to defeat the purpose of top screen.
    At the same time, I am thinking about doing my first decoction on next brew.

  8. vito: on homebrewtalk, there are people who have compared solid sided vs mesh sided… and the efficiency seems to be the plus on the mesh sided… i think you also can fly sparge with mesh-sided – but you have to put it over the bed really slow… perferably by a good sparge arm (like ultimate sparge arm or the ss brewtech manifold or similar).

    Also, the mesh sided does also form grain bed – but not as compact, since you always will have flow through the sides also.. but all in all, the gravity is downwards.

    As you say, there is no perfect solution. I’ll soon order a mesh sided, and let you know how i like it.

  9. Thanks, but my issue isn’t about the PID algorithm.
    It is about the separation of wort/mash that causes difference of temperature.

    I used to adjust the valve so that the wort doesn’t drain from the overflow pipe. Because the wort drains through the grain bed slowly, the PID algorithm was actually applied to the wort at the bottom, which is about 2 gallons. It explains why the parameters derived by 2 gallons of water worked better than that from 4 gallons of water.

  10. Ok. Understood.
    Current PID library works fine for me. The separation of wort is my real issue.
    BTW, I’ve finished the new version for mash-in temperature but don’t have time to test it yet.

  11. Are there any instructions on how to completely setup the ESP8266 with the latest firmware and web pages? I am trying to get the v0.2 firmware running and am having issues. I can compile the firmware in the Arduino environment and download it to the ESP8266, but when I connect over WiFi to the BrewManiacEx, it shows firmware 0.1.2, and I am not able to upload new firmware or the latest web pages. I am really confused as to how to get this all setup and I have read the manual to no avail. Any help would be appreciated.

  12. 1. You have to update the HTML/Javascript files, which is in the “data” folder
    2. You might need to clear cache of your browser or force it to reload the page.

  13. How do I do that? Quite honestly this is a complex setup, although it is very powerful, but I’m not sure I really understand how it all works. I think some simple steps that take someone from compiling the arduino project, to downloading the program, and then how to connect to the BM and update firmware and HTML/JavaScript files would be very helpful.

  14. 1. file manager
    http://bm.local:8008/filemanager

    Update the files in “data”. You should only need to update
    bm.js
    index.htm
    version.txt

    2. OTA (I have trouble setting up the server, so it might not work sometimes.)
    Browser to
    http://bm.local/update
    You can check the version and latest version.
    The files can be requested to be downloaded automatically. Internet access is necessary though.

  15. Thanks Vito, I think I figured it out now and have been able to update the web page files.

    On another note how do I go about letting you know about bugs I have run across? I found a few things I wanted to pass along.

    Finally what are the versions of the various Arduino libraries that you are using?

  16. Sure. Please let me know if you find any bugs.
    There is a test or verification team. I don’t have the time to do a full test.

    I’ve uploaded the libraries on Github. Some of them are modified when necessary.
    For example, the WiFiManager has been modified so that there is a way to stop the WiFi setting mode.

  17. What is the best manner in which to report bugs? Should I post on git, would you rather I email you directly, do you prefer something else? Just let me know as I am happy to report anything I come across.

  18. I cannot find the libraries on Github, unless they are the ones that are mentioned in the readme of the BMESP8266 repository.

    Before I do any serious testing and provide feedback, I need to make certain that I have everything configured correctly and I am using the same source code and libraries that you are using. It would be quite helpful if there was some basic documentation that explained setting up the arduino environment, downloading and installing the correct libraries, and compiling.

  19. Vito having read the above few comments about updating the webfiles it mirrors a few of the issues I had before I knew what I was doing, I’ll take another look at that section of the manual and see if I can put something together that covers it. I’ll send it to you in the usual way when done.

    FYI I’ve not had any issue with the server update recently.

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