Missing My Marks...

Discussion in 'Beginners Brewing Forum' started by Steve SPF, Jul 21, 2019.

  1. Steve SPF

    Steve SPF Well-Known Member

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    Hi folks, any thoughts on where I've gone wrong here?

    13 kg Pale 2-Row 38 2.5 91.5%
    1.2 kg Torrified Wheat 36 2 8.5%

    100 g Magnum Pellet 9.3 First Wort
    70 g Nelson Sauvin Pellet 12.5 Boil 15 min
    70 g Cascade Pellet 7 Boil 15 min
    70 g Nelson Sauvin Pellet 12.5 Boil 5 min
    70 g Cascade Pellet 7 Boil 5 min
    60 g Nelson Sauvin Pellet 12.5 Whirlpool at
    140 g Cascade Pellet 7 Whirlpool at

    Method: All Grain
    Boil Time: 60 min Batch Size: 75 liters (fermentor volume)
    Boil Size: 90 liters Efficiency: 70% (brew house)
    Boil Gravity: 1.035 (recipe based estimate)

    Original Gravity:1.042
    Final Gravity:1.008
    ABV (standard):4.45%

    The ABV was supposed to be 4.45% which was ideal but the OG came out at 1.036 so I've ended up with substantially weaker beer. I'm ok with it because it tastes fine at this stage, it's just finished fermenting today, so it's not a dumper by any stretch but I can't see where I went wrong.

    I thought I had the mash temp spot on at 66 for 1 hour so was quite confident but when I did the OG after the boil it was at 1.036 which was a real surprise. I guess it's two queations really:

    1 - What was my initial error?

    2 - What could I have done about it once the boil was finished?

    Thanks for help.
     
  2. Trialben

    Trialben Well-Known Member

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    My first thoughts are hopefully you mashed in well and incorporated the grains well into your mash water. Giving it a good stir again in 15minites time helps to break up any stubborn dough balls if you didn't get them when mashing in. I find the grains are a bit easier to manage after they've been mashing a bit.

    Another one can be grain crush may be a different crush from previous brew. I BIAB so a nice fine crush suits my brew style.

    A 60minute mash should be plenty of time at that temperature for complete conversion I always employ a mash step to 71c to Finnish of any unconverted starches but I'm not sure this matters just brew habit but maybe something you can try.

    I'm gathering if you've been hitting your efficiency last few brews you could just notch this one up as an anomaly.

    See what everyone else thinks.
     
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  3. Steve SPF

    Steve SPF Well-Known Member

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    Thanks. I felt that the mash was fine, no doughballs that I could see and stable temp. I can't change the mash temp though so stepping it up isn't an option. I do make sure that there's plenty left in the HLT at the right temp though so there's no real drop off in mash temp at the end.

    Efficiency has been good and when I've made mistakes previously I've understood them so can learn and move on. This one has me scratching my head.
     
  4. Megary

    Megary Well-Known Member

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    Just curious...How did you measure your OG? You say you measured gravity after the boil, so I'm wondering if it isn't something as simple as just correcting the gravity reading for the temperature of the sample.
     
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  5. J A

    J A Well-Known Member

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    Efficiency is a function of gravity and volume. You mention only gravity and not pre- or post-boil volume so it's not easy to make any guesses about whether your efficiency was less than projected or your volume is off and causing increased dilution. Your target efficiency of 70% is reasonable and, depending on mash thickness and sparging method should be pretty easily attainable.
    If you can detail accurate volume readings and a little more info about your process, it'll be easier to speculate about what you might be able to change for next time.
     
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  6. Hogarthe

    Hogarthe Well-Known Member

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    Maybe your boil wasn't as vigorous this time? Stronger boil will evaporate more water and give you higher gravity.
     
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  7. Steve SPF

    Steve SPF Well-Known Member

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    Interestingly, it isn't in my notes so I didn't do it properly. I usually cool a sample down in a cold water bath which is what I did but failed to take the temp. Could be as simple as that?
     
  8. Steve SPF

    Steve SPF Well-Known Member

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    Well, it seemed to be quite efficient. 90lt is a lot in my kettle so it was more like 85lt, I can't measure the fermenter exactly but it looks to be around 70lt (won't be far off). The recipe called for 21lt of mash water but that seems less than ideal in my kettle so I use more like 40lt. I can keep the HLT up to temp so am sparging at 67°.

    Have to say that the recipe building tools here are brilliant, and thanks to all for sharing their knowledge. I've a lot to learn but feel that I found the right place :)
     
  9. philjohnwilliams

    philjohnwilliams Well-Known Member

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    This won't help solve your problem, but it because of brews like this that I take a gravity reading before I start my boil. The recipe builder here on Brewer's Friend will show you your (pre) boil gravity and if you are off your mark pre boil you can make corrections (eg boil off some water if your gravity is too low or add some if too high). I have had a few brews where I was able to save a mistake by taking a reading before the boil, and using a refractometer makes this super easy.
     
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  10. Steve SPF

    Steve SPF Well-Known Member

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    Ah, interesting. I didn't know we could do pre-boli. Every day's a school day :)
     
  11. Craigerrr

    Craigerrr Well-Known Member

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    I had one brew a while back where my preboil gravity was way low, but my volume was smack on. I presume it was due to undercrushed grains. I added some DME to bring the gravity up. Worked like a charm. The batch I brewed Friday night, I was 3/4 of a gallon over volume (10 gallon batch), and a little under gravity. I boiled until I hit my gravity, then set the timer and added my 60 minute hop. After the 60 minute boil I was smack on gravity, but still over volume. No problem,I just filled the two fermenters to the desired level and ditched the extra wort. Always a work around.
     
  12. J A

    J A Well-Known Member

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    I think you're missing my reference. The efficiency that you noted in the recipe is 70%. That's the figure that's used to predict how much of the starches in the malt you'll convert to sugars. If you converted all the potential starches you'd have 100% efficiency. You've predicted that you'd achieve 70% of that based on how much was converted during mashing. Since this example uses the brewhouse efficiency and with the final volume based on what goes into the fermenter, the efficiency number takes into account what is lost in the process of transferring from the kettle.
    If it had actually been quite efficient, you'd have gotten at least 75 liters of 1.042 wort into your fermenter. Based on getting 70 liters of 1.036 gravity wort into your fermenter, you actually got about 56% efficiency.
    The reason I mention volumes (and I'm only referring to post-boil and/or fermenter volume in relation to the OG) is that there are only two possible reasons for your much lower efficiency. You either didn't convert nearly as much of the potential starches in the mashing process or you converted the starches but diluted them in a higher volume of water so that the gravity of the final wort is lower. If you had an extra 15 liters or so of wort left in your boil kettle that you didn't use and therefore it didn't make it into the equation, your conversion efficiency would have been higher and dilution would be the problem. If you got pretty much everything after boil into your fermenter then your actual conversion efficiency during mash is bad.
    Using Fermenter as the target for efficiency requires that you get your system profile dialed in so that you account for all the losses that occur throughout the process. I suggest that to simplify things you use Kettle as the target setting so that you can get a better measure of final post boil volume and with that as well as an accurate gravity reading, you'll have a better idea what your actual conversion efficiency is and be able to accurately predict your OG and adjust your grain bills accordingly for future brews.
    In the meantime, keep a few pounds of malt extract around. If you'd added a couple kg of DME to the fermenter, you'd have been back up to your desired gravity.
     
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  13. J A

    J A Well-Known Member

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  14. Steve SPF

    Steve SPF Well-Known Member

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    Thanks for input folks, much food for thought here. I will definitely switch to kettle voulme rather than fermenter, that makes perfect sense, and also make sure I get my temp right for testing post-boil. I will have a look at pre-boil readings as well, again an idea that makes a lot of sense. Oh, and make my note keeping more accurate as well :)
     
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