Results 1 to 10 of 10

Thread: Every brews are getting very low final gravity

  1. #1
    Join Date
    Apr 2018
    Location
    Hong Kong
    Posts
    2

    Unhappy Every brews are getting very low final gravity

    Hi everyone! I have just started test running the equipment and am very new to this brewing business. I have encountered so much problem regarding mashing and fermentation.
    I currently am running a 600L electric system from China with HLT, MLT and BK. Aside from a few design flaws I have managed to fix most of them.

    However I have been seeing a problem on all of my test batches that had been done on homebrew system all the time. The FG had constantly been very very low, usually 1.006 while one got to even as low as 1.004. (It was 1.010-1.011 in homebrew scale)
    I am currently just testing a very simple pale ale with only Gladfield malts: 2-row , wheat malt and 20L crystal malt.

    Here's my process of several batches that I have been messing around:
    Mash at around 67-68C (152-154F) for 60min (single step infusion)
    Vorlauf for either 20mins or up to 60mins till clear with a wort grant
    Run off and sparge, it takes around 2 hours for the whole thing to be transferred to BK
    After boiling it is oxygenated, and transferred to FV and US-05 is added.

    My question is, is there something to do with such long process including mash, runoff and sparge causing the wort to be very fermentable? If so, is there any way to combat this or are there any more potential cause of this?

    Thanks!
    -Alex

  2. #2
    Join Date
    Sep 2012
    Posts
    37

    One more piece of info needed...

    Original gravity? That will allow you to calculate your attenuation, and see if it's "in bounds."

  3. #3
    Join Date
    Oct 2002
    Location
    Chesterfield, UK
    Posts
    1,822
    My first step would be to reduce the vorlauf to 5 minutes, which will reduce the time the enzymes have to work. If you have a system with rakes in and are raking whilst vorlaufing, I would also turn off the rakes until you start to sparge. Second step, as a follow on, not at the same time, would be to raise the mash temperature a degree at a time and see what the results are. If you do the two actions together, you don't know which is having the greatest effect on FG. Personally I consider long vorlaufs a waste of production time with no real benefit compared to the time lost.
    dick

  4. #4
    Join Date
    Apr 2017
    Location
    San Antonio
    Posts
    4
    How long does it take to reach the final, lower gravity? How does it taste? Are you using the exact same malt and water as you were for the homebrew batches?

  5. #5
    Join Date
    Jan 2009
    Location
    Abingdon, VA.
    Posts
    203
    This may be stupid because you've thought of it already, but I had two hydrometers get old and showing consistent final gravities around 1 Plato. Not my first suspicion but replacing them solved our problem. I assumed maybe they get heavier somehow with age.
    _______________________
    Chris Burcher, Wolf Hills
    Abingdon, VA

  6. #6
    Join Date
    Apr 2018
    Location
    Hong Kong
    Posts
    2
    Thank you everyone for the advice and input! I really appreciate it!

    Quote Originally Posted by MikeyB View Post
    Original gravity? That will allow you to calculate your attenuation, and see if it's "in bounds."
    My original gravity was around 1.054.

    Quote Originally Posted by dick murton View Post
    My first step would be to reduce the vorlauf to 5 minutes, which will reduce the time the enzymes have to work. If you have a system with rakes in and are raking whilst vorlaufing, I would also turn off the rakes until you start to sparge. Second step, as a follow on, not at the same time, would be to raise the mash temperature a degree at a time and see what the results are. If you do the two actions together, you don't know which is having the greatest effect on FG. Personally I consider long vorlaufs a waste of production time with no real benefit compared to the time lost.
    I will try this for the next batch. I always worry that the long runoff (including sparge) is creating this difference (compared to homebrew). I am currently matching the pump speed to the flow rate from the MLT to the grant, it is as fast as I can get and wort never really gets clear, I supposed some particles going into the BK won't hurt.
    For the rakes, I currently only use it very slowly for maybe 3-5 minutes during dough-in for mixing the malt and water. Should I be using the rakes during sparge?
    For the second step you suggested, I will see if that helps too! The problem is that with this MLT, it is only insulated and no way to maintain the temp throughout the mash, e.g. 60 minutes. It drops for around 1-2 degrees during the period. Temperature of wort drops even quicker during vorlauf and runoff due to heat loss from pipes.
    I always thought 67-68 degrees would achieve a less fermentable wort and also for 60 minutes the enzyme would have been denatured.

    Quote Originally Posted by Weehe View Post
    How long does it take to reach the final, lower gravity? How does it taste? Are you using the exact same malt and water as you were for the homebrew batches?
    It takes around 7-8 days to achieve a stable final gravity. The malt and water are the same, this is getting very confusing as I've never thought switching from homebrew to "probrewing" is that difficult.

    Quote Originally Posted by burcher View Post
    This may be stupid because you've thought of it already, but I had two hydrometers get old and showing consistent final gravities around 1 Plato. Not my first suspicion but replacing them solved our problem. I assumed maybe they get heavier somehow with age.
    I just took your advice and further confirm the results with a hydrometer and an Anton Paar EasyDens. Everything seems to be working fine.

  7. #7
    Join Date
    Oct 2002
    Location
    Chesterfield, UK
    Posts
    1,822
    "The problem is that with this MLT, it is only insulated and no way to maintain the temp throughout the mash, e.g. 60 minutes. It drops for around 1-2 degrees during the period."

    That is absolutely standard design. It is common to lose a little around the edges, but you shouldn't lose 2 deg C.

    Two thoughts - one is that the insulation may not be very good - how thick is it? and what sort of insulation? PU foam, mineral wool, glass fibre? Other? unlikely now, but they used to use cork, or simply wood cladding

    Second thought - do you thoroughly pre-heat you mash tun (to circa 65 C) before starting to cover the plates, and then mashing in?
    dick

  8. #8
    Join Date
    Oct 2015
    Location
    USA
    Posts
    7
    You haven't mentioned what yeast you are using. Not sure how you are oxygenating but you could be adding much more than your home brews. At your mash temp most of the conversion should happen in the first 20 minutes so a loss of mash temp shouldn't be your issue. How do you feel about your fermentation temp control. Do you have a secondary thermometer on tank to assure you are at the right temp?

  9. #9
    Join Date
    Jan 2016
    Location
    Shoreacres, BC
    Posts
    4

    Some tweaking necessary

    Alex, it doesn't seem you are very far off from where you should be. You are getting close to 90% attenuation, which is a little high for US05. Fermentis shows 81% attenuation on their data sheet, but it is not unusual to exceed the manufacturers specified attenuation on a commercial system, in my experience. That said, I just got 87% attenuation using US05 on my last home brewed batch. You might want to calibrate your thermometer that you are using to test the mash (along with every other thermometer in a new system), as just a degree or two difference can make an impact on fermentability (and body and efficiency, etc). Take multiple mash temperature readings to get an average. It shouldn't vary too much after mixing with the rakes. What is your pitch rate for the yeast? US05 comes in 500 g bricks which is enough for 10 hl. If you are getting consistent 7 day primary fermentations that is good. Keep Vorlauf at 20 minutes, or a consistent time. Vorlaufing for 5 minutes will get rid of a lot of the grain that comes out initially, but will not achieve wort clarity. Don't run your rakes after your bed is set if you don't have to (not getting stuck mashes). Change one thing at a time. If you want to reduce fermentability, try to increase your mash temperature in 1 degree increments until you get the product you want. If you are still getting too dry a product, consider using another yeast with lower attenuation. Make sure your gravity readings are correct. Most commercial brewers use Plato hydrometers with temperature correction.

    You are on the right path...good luck!

  10. #10
    Join Date
    Dec 2003
    Location
    Strongsville, Ohio
    Posts
    289
    Hmmm.....have you compared the temp probes/thermometer readings on your homebrew gear vs your new system? I would try to get the sample in your sacc range (152-154f)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •