A bit of help...

Discussion in 'General Brewing Discussions' started by Blackmuse, Jun 14, 2021.

  1. Blackmuse

    Blackmuse Well-Known Member

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    So, as many of you know, I recently snagged the 65L Brewzilla a couple weeks ago. Well, life and a bit of intimidation kept me from using it - until yesterday... Now, as with every new system there are some learning curves to overcome. What I can say in short is: I kept my cool and overcame all the obstacles in one way or another - that I am proud of.

    The longer story is this:
    In the end, my conversion did not go as planned - Pre-boil gravity was 1.038 vesus 1.056! Post-boil gravity was 1.049 versus 1.063... What caused this? My guess is the mash temperature. This is what I need help with - is it the right assumption and how should I go about correcting it?
    Note: I typically use 4 degrees as an offset for my 35L Robobrew and did so in this brew session with the Brewzilla.
    So, here's what I noted during my mash:

    1. I mashed in at 158 (4 degrees higher than my intended rest temp) and attempted to keep the mash in this range (I intermittently recirculated with the pump during mash-in to move the wort off the probe at the bottom and help wet the grain at the top).
    1a. Once mash-in was complete, my brewzilla was raising temp back up to 158 (from 156) but a temperature probe stuck in the middle of the mash read 139! (Nearly a 20 degree difference!)
    1b. What did I do? Nothing - I have seen a roughly 8-10 degree difference in the 35L but only used a 2-4 degree offset with better results than the one time I tried a 10 degree offset.

    2. During the mash I recirculated constantly as I do with the 35L version which I had hoped would balance the temperature out in the grain bed (which is what I found typically happened in the 35L).
    2a. A temperature reading at the top of the recirculated wort near the output only read 140-141!
    2b. What did I do? Not much, I started my mash out temperature raise 10 minutes early.... I assume this may have been a bit of a saving grace?? lol

    By the end of the boil I was 13 points shy of my intended OG - So, I added roughly 2LBS of LME I've had on hand for some time... (My only real option shy of honey or maple syrup - I figured the beer would already be thin enough) and I got the OG up to 1.060 but I also boiled for an extra 20 minutes or so. I ended up with 9.75 gallons of wort instead of my intended 11 - so I need to adjust my equipment profile a bit too.

    Additional note - I did an initial test of the brewzilla temp probe versus the same one used to double check the mash and both read within 1 degree of each other with just tap water in the brewzilla.

    So, would a sub 140 F significantly lower my conversion (my thought is yes...) and should I use a 20 degree offset or start somewhere around 10? What I don't quite understand is how it can read 158 at the bottom and then 141 at the output of the recirculation tube!

    Is there something else I might be missing? - I did not test pH but used BF and salt/mineral additions to adjust the intended pH.

    Here's the recipe: https://www.brewersfriend.com/homebrew/recipe/view/1147713/shuttz-nut-brown-10g
     
  2. Craigerrr

    Craigerrr Well-Known Member

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    Did you stir the mash at all?
    Just wondering if you had some channeling going on

    When you are talking about temperature offset, what do you mean by that?
     
  3. Blackmuse

    Blackmuse Well-Known Member

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    Once I finished doughing in I did not stir the mash at all...

    Offset being the stated temperature on the unit's display versus what a secondary reading gives me in the grain bed.
    - On my 35L I set my unit 2 to 4 degrees higher than my intended mash temp since the rading comes from the bottom of the unit versus in the grain bed.
     
  4. Minbari

    Minbari Well-Known Member

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    Depending on how far off those temp readings are. You are starting to push the boundary of where the starch converting enzymes die off.

    Check your temps with a stick thermometer and verify.

    I always use the grain bed temp. The recirc temp has added heat that makes it somewhat unreliable
     
  5. Blackmuse

    Blackmuse Well-Known Member

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    Yeah, I think I may try this on the next brew. The only issue is I like to use the top screen and recirculate during the mash... Maybe I can stick the probe down inside the overflow tube and I might get a "close/closer" reading. Maybe it is time for some trials....
     
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  6. Blackmuse

    Blackmuse Well-Known Member

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    My guess is that I never really even hit the true conversion temps 142+ - at least not until the end of my mash when I raised the temp to 170 and was finally in the 150 range for about 15 minutes.
     
  7. Minbari

    Minbari Well-Known Member

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    I recirc as well. I use a HERMS / RIMS combination. I use false bottom biab setup and my temp probe is below the bag, so I know what the runoff temp is.
     
  8. Minbari

    Minbari Well-Known Member

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    That would do it too.
    One thing to try. Gets a tincture of iodine. Every 15 minutes you take a drop of wort on a white surface. Put a drop of oidine next to the wort. If the oidine turns black. Yoy still have unconverted starch
     
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  9. J A

    J A Well-Known Member

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    Grain bed temp is not as important in a recirculating system. The enzymes are free-floating in the mash liquor and the temperature of that is what determines whether said enzymes are "turned on" or not. If you use grain bed temp in a HERMS/RIMS system, the mash liquor can go substantially over the intended temperature in attempt to heat the grain and in the process denature the enzymes.
     
  10. Donoroto

    Donoroto Well-Known Member

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    I am fairly confident that the poor conversion is from low temperature, as evidenced by your readings. The 'problem' is the temperature probe's location, the metal bottom conducts the heat from the coils to the probe, artificially elevating the displayed reading. I suspect your 35 l BZ's offset of 4 degrees is incorrect for the 65. A couple of brews with careful temperature monitoring will get you closer.

    I also use the top screen, and I used a drill to enlarge a couple of the top screen holes to allow my long probe thermometer to set in the mash bed. The 'clip' for the thermometer keeps the head above the wort level. After doughing in and allowing the system to settle for maybe 5 minutes, I recirculate at about half-throttle for the entire mash. I tried not recirculating, and the bottom of the mash got too hot while the top was too cool. Recirculating evened it out nicely.

    I recommend that you simply ignore the temperature reading on the display panel and use your thermometer exclusively. Of course, note your temperature settings and readings for later reconciliation, but go to full manual control and use the thermometer. Recirculate the whole time, or at least the first 1/2 - 3/4 of the mash time, to ensure uniform temperatures. After a couple of brews, you'll be able to dial it in closer and closer until it is spot on like the 35.

    Keep us advised of your progress!
     
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  11. Minbari

    Minbari Well-Known Member

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    No doubt. The herms is never much above the grain temp once temp is reached. For the temp controller to maintain temp. I use the grain temp
     
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  12. J A

    J A Well-Known Member

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    #12 J A, Jun 14, 2021
    Last edited: Jun 14, 2021
    I used to have only a sensor in my mash tun and worried a lot about the difference in the liquor and the grain bed but now I've got temp sensors in my mash tun and also inline where my mash liquor comes out of the HERMS coil. I use the liquid sensor for temp control and it does a great job of raising the temp for steps and maintaining within a degree and a half or so. I monitor the grain bed to see how effectively the whole system is heating and how much the mash is cooling as it circulates through. Since I stir a few times during mashing, the grain bed catches up fairly quickly. When I'm mashing out, I don't stir and even though the enzymes should be denatured as soon as the liquid temp is running steadily at 168, I let it recirculate until the grain bed temp reaches 168. Seems to work well. :)
     
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  13. Trialben

    Trialben Well-Known Member

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    I'd say also that your stike temperature was down as well. I find doughing in at the right strike temp helps even out the grain bed temp avoiding any see sawing on the mash temp.

    If I read that low a temp I would of extended the mash time and tried to up the mash temp into the Sac range whilst giving the top half or so of the grain bed a gentle stir.

    But agree you've got some experimenting to do
     
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  14. Blackmuse

    Blackmuse Well-Known Member

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    Hmmm. You know, this was one of the first times I didn't set a strike temperature and instead doughed in at infusion temp... I'll be sure to adjust for that.
     
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  15. Blackmuse

    Blackmuse Well-Known Member

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    Thanks everyone for the input! Good to know that my thoughts were going in the right direction. I'll experiment some more starting with where to take temps. Next brew I will try and meet in the middle of the two probes. Probably start with a 10 degree offset. I think 20 is a bit much.

    I was thinking of doing exactly this thing! Good to know someone else has already done it. I will try this.

    I'll keep you all posted!
     
  16. J A

    J A Well-Known Member

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    It's obvious that you don't have system setting dialled in and when you calculated the recipe, none of your intended numbers was going to necessarily correspond with your results. I think it's likely that you just had an efficiency setting way too high for the system and the first place to look for low gravity is there. Calculate your actual efficiency for this batch and use that for the efficiency to calculate your next batch. There may be other factors at play but that's where you have to start.
     
  17. Craigerrr

    Craigerrr Well-Known Member

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    I was thinking this very thing, once I dialed in strike temperature on my 35L life got easier.
     
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  18. Craigerrr

    Craigerrr Well-Known Member

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    What are the wattage on the elements? Are they one @ 500, and one @ 1900?
     
  19. Blackmuse

    Blackmuse Well-Known Member

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    One 500, one 1000 and one 2000.

    I used all three for the boil but should have only used 2,000 to 3,000 once it got boiling - I think that is part of why I boiled more than expected (that and extending it by 20 minutes).

    Honestly, not a great first experience but it could have been way worse. I learned a lot though and did well to overcome the setbacks.
     
  20. Blackmuse

    Blackmuse Well-Known Member

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    In other news - I split the batch and am fermenting one with Cali yeast and the other with Windsor... The Windsor was ripping away at it this morning but looks now like its flocculating out - the krausen dropped out almost completely. Anyone ever seen that with Windsor? I've only ever used it one other time 8+ years ago. - My guess is it hit its growth phase rapidly and will churn through things slowly from here on out....
     

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