Way low OG

Discussion in 'General Brewing Discussions' started by Hoptonium, Mar 20, 2020.

  1. Hoptonium

    Hoptonium New Member

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    #1 Hoptonium, Mar 20, 2020
    Last edited: Mar 20, 2020
    Hi Folks, first time poster, sorry if this is in the wrong place.
    I copied a Maibock recipe from HighVoltageMan! and totally missed on the OG.

    upload_2020-3-20_10-43-43.png

    My measured OG was 1.042, which will result in a pathetic ABV of 3.81% if the rest of the brew goes to plan. I am also worried that I'm going to be missing a lot of flavor
    This was the first time I tried to use a cooler based mash tun so I'm thinking I may have done something wrong. This was my mash plan:
    1. Strike water, 13.2 L at 70C, added all grains, temperature dropped to 63C. Put the lid on.
    2. Checked the temp at 15 minutes, it was 62.7C. My mashtun loses about 1 C/hr.
    3. Steeped for 60 minutes and drained.
    4. Sparged with 14.7 L at 75C, twice - I didn't let the sparge sit long, maybe 5 minutes - maybe that was the problem...?
    As I am new to the cooler based mash tun I am sure there is something I missed.

    Another possibility for the low OG reading: I use a standard hydrometer and measured the OG after pouring the cooled wort from the kettle into the fermenting bucket. I am wondering if the vigorous churn from the pouring temporarily causes the wort density to decrease because of the "trapped" air...? By measuring after pouring my reading was off...?

    In any case, I will measure the density today after 24 hours of sitting in the fermenter to see if my alternate theory is correct. Otherwise, a couple of questions:
    1. Did I miss, or botch, a step in the mashing?
    2. Can I recover the brew by adding some extract? If so, can you step me through that process?
    Thank you for any help you can provide,
    Anthony
     
  2. Bubba Wade

    Bubba Wade Well-Known Member

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    The only thing I see that jumps out at me is your mash temperature. 62 °C is about 144 °F. I usually try to stay in the 150-153 °F (65.5-67.2 C) range, but I know other do mash down at the same temperature that you used.

    Without more details on your sparge, it is possible that you lost a few gravity points there.

    I don't think you hygrometer was off by using aerated wort. Air is not that soluble in water.

    Check your gravity again. You can use extract to bring up the gravity. Boil some water and dissolve the extract. After it cools, you can pour it in. If you don't want to increase the volume in your fermenter, you can use some of the wort in your fermenter and add the extract to it. Just boil it first to sanitize and to make the extract easier to dissolve.
     
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  3. AGbrewer

    AGbrewer Active Member

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    The efficiency listed (84%) seems a bit high. Are you sure that your system gets that? Is that your eff or his eff. Perhaps you simply came in at a lower eff? Didn't do the numbers, but if you are at 70% and his recipe is calling for 84%, that would explain some of why you missed the OG.
     
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  4. Hoptonium

    Hoptonium New Member

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    Thanks Bubba, I just did a gravity reading and its pushing down to 1.03 with a pretty evident fermentation - so you are correct, not much issue with the measurement of OG.

    As far as the sparge - I drained the strike water and set that aside in the kettle. I closed the mash tun valve and dumped the 14.2 L of 75C water on the grain in the mash tun, let it sit for about 5 minutes, drained that into an empty bucket, then poured that back over the grain, didn't let that one sit but a minute or two. That's basically it. Then poured it into the kettle.

    Regarding adding extract. I'm already at a fairly rigorous fermentation and I won't be able to get the extract until mid-week next week - I assume it would still be OK to add the additional fermentables at that time...?

    Thanks for your help!
     
  5. Hoptonium

    Hoptonium New Member

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    Thanks AGbrewer, yeah, I saw that after I was scratching my head wondering what went wrong. The 84% is definitely not my efficiency - as you said, it was just copied over from the original recipe - but to get from 1.066 down to 1.042 my efficiency would be more like 54%. I've never been that far off before, but since this was my first time with my cooler mash tun maybe (clearly) it was that bad!

    Cheers!
     
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  6. Bubba Wade

    Bubba Wade Well-Known Member

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    Yes, you can add the extract during fermentation. Just be careful with the sanitation. As noted before, I would dissolve the extract in boiling water to sanitize it and to fully dissolve the extract. It will need to be fairly concentrated in order to keep from increasing the fermenter volume too much. So it may seem pretty thick when you add it. However, it will dissolve. Unless you have a sanitized spoon (and even if you do), I would resist the temptation to stir the fermenter. The thicker solution will reach an equilibrium with the lighter solution.
     
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  7. Craigerrr

    Craigerrr Well-Known Member

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    I have only been at this for about two years, so this is not an expert opinion, but I would personally not want to be adding some fermentables after fermantation. Oxygen ingress when pouring it in would be one concern, the other would be a minimal potential of contamination in the process. Not sure what you were hoping to achieve by reintroducing the second runnings to the grains and draining again. Think of it like rinsing your clothes in the same water twice...
    When I mashed in a cooler I only did one batch sparge, and had decent efficiency. Once I went to larger batches I did three runnings, but that was a capacity issue. Second and third runnings were fresh hot liquor.
    Your worst case scenario here is that you made a 4.2% sessionable beverage:D.
    Good luck with it whatever you direction you go.
     
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  8. Nosybear

    Nosybear Well-Known Member

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    I do it all the time, DME, sugars, syrups. Go ahead and add them: Boiling will drive most of the oxygen out of the addition and the yeast will consume the rest. Actually, that weird sparge may have been the cause of the low OG: You're trying to dissolve sugar with a higher concentration of sugar - leveled out the sugar content in the second runnings. I batch sparge with decent efficiency but, as Craigerrr mentions, only with hot liquor.
     
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  9. Craigerrr

    Craigerrr Well-Known Member

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    Nosy knows!
     
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  10. Hoptonium

    Hoptonium New Member

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    Thanks again Bubba - I will add some DME when it arrives next week - boil it like you said. The question now is - how much to add? Without knowing exactly how to calculate it, I used the Brewer's Friend recipe calculator with the original recipe. I put the efficiency to 100% and adjusted the original grain amounts down until the calculated OG = measured OG = 1.042. Then I added 1.5 kg of DME-Extra LIght (2.5 deg-L) which adjusted the calculated OG to 1.072, the FG to 1.015 for a ABV of 7.5%.

    Does this seem reasonable? I put the efficiency to 100% because I assume all of the sugar from the DME gets into the fermenting bucket, so I am just trying to calculate the additional ABV due to the added DME. Unless "efficiency" in the recipe editor starts further back in the process then I think this would work. But if I need to take into account the DME maker's efficiency starting from the bulk grain, then I don't really know what value to use for efficiency...
     
  11. Hoptonium

    Hoptonium New Member

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    Thanks Craigerrr - I wish I could recall where I got the idea for the second sparge run using the water from the first - but it has been lost in the cobwebs of my mind. :confused:
     
  12. Hoptonium

    Hoptonium New Member

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    Thanks Nosybear, I'm going to give the DME add a try - and never do that odd second sparge again!
     
  13. Bubba Wade

    Bubba Wade Well-Known Member

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    That will get you pretty close. I’m usually pretty happy when I am within 2 or 3 points of target.
     
  14. Hoptonium

    Hoptonium New Member

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    Quick update for all you brewers waiting on the edge of your seat! :p
    The addition of the DME after the initial fermentation was done worked just fine. My Maibock was quite tasty and pushing 7.7% ABV.
    Thanks for all your help fellow brewers!
     
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  15. Frankenbrewer

    Frankenbrewer Well-Known Member

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    Another experiment saved by the "Masters"
     
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  16. HighVoltageMan!

    HighVoltageMan! Well-Known Member

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    First of all, I'm flattered you used my recipe. That's pretty cool. Thank you.

    The efficiency of my system is between 85-92%, which is a little unusual for home brewing. I always thought it was because of my RIMS system. I know I lot of other brewers use coolers, which hit closer to 65-75%. It's not a big deal, you just have to adjust the recipe. DME works to boost gravity too, I do that once in a while as well.

    The lower mash temperature is needed to create a really fermentable wort, 150F and above will give the impression of sweetness. The lower temperature doesn't necessarily reduce extraction efficiency, but longer rests will not only improve conversion, but it's also necessary to allow the beta enzyme more time to work to create the simpler sugars needed for a dryer beer. Lower temperatures slow the sach rests down and they just need more time, 90 to 120 minutes. The pH plays a role in efficiency too, a room temperature pH of 5.4-5.5 will give you the best overall efficiency. I use all RO water in this recipe, along with acid additions to keep the pH low.

    The other thing to remember as a rule of thumb, the higher the gravity, the larger the grain bill, the larger the grain bill, the lower the efficiency. When I brew big lagers like that, I lower the post boil volume to 4 gallons or so. The starting gravity of the boil can be as low as 1.040, but the boil volume is pretty high, 6-7 gallons. So it means a long boil. It's not uncommon to boil for 2-1/2 to 3 hours (there is a temptation to drink the whole time, but I don't recommend it). Long mash/boils and big German beers go hand in hand. Other reasons to keep the post boil volume down are you don't need as much yeast to keep the pitch rate high and the finished beer is really good, but I don't need a lot of a 7% lager around the house. They go down fast and it gets me into trouble.

    Funny thing is, I was going to brew this beer again soon for the fall season. Miabocks are perfect for when the temperature starts to drop.
     
  17. Hoptonium

    Hoptonium New Member

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    You're welcome and thank you for posting it! The information on the mash temperatures and times are great and I will follow that for the next time - and there will definitely be a next time.

    Here's a picture of the finished product - taken on 14-May.

    Cheers!

    IMG-2509.jpg
     

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