Efficiency % and OG Measurement

Discussion in 'General Brewing Discussions' started by MrBIP, Oct 8, 2012.

  1. MrBIP

    MrBIP Active Member

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    So, here's a question from the newby....

    I put my first brew in the calculator long before starting (it's an extract with some steeping grains; and I did go ahead with real pumpkin too) ... calculator said my OG should be 1.058, I used 30% efficiency in the caculator.

    I ended up at 1.060-1.061 when it went into the fermenter.

    Now, after steeping grains and pumpkin and bringing the volume up to 3 gallons (temp was probably 155-160 range, but I didn't check it?) .. I had a gravity of 1.015

    I put the grains and wort volume that I had into two different brewhouse efficiency calculators and it's giving me 37%; not considering the pumpkin.

    So.... the gap between 30% and 37% might explain the 2-3 point difference in expected vs actual OG? Or am I over-simplifying something that should only be used in all grain brewing? (and perhaps I needed to pay attention to tempuratures and adjust for this?)

    The yeast I used says on the package up to 1.060, so I guess I'm pushing it, getting a few bubbles now, so hopefully I'm ok.

    I've got Papazian Homebrewing book and will crack that open tonight, but I'm in impatient fellow on my quest to learn and I know there are experienced brewers here ... :)
     
  2. chessking

    chessking New Member

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    Actually, You might be over complicating things. A three gravity point difference is fine, (assuming you have corrected for temperature). I rarely hit my OG dead nutts on. I'm giddy as a schoolgirl to get within three points. The beer will be fine. The yeast know what they are doing. If you have pitched the proper amount, at the correct temperature, at that point, leave it alone. In three or four weeks, bottle/keg it and again, leave it alone. In another month, when you are drinking it, you wont be thinking "this tastes about three gravity point over". You will be saying "WOW! This is some fantastic beer I have made!". Cheers.
     
  3. MrBIP

    MrBIP Active Member

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    LOL, thanks, I've got some slow bubbles coming out now, so I think the yeast are doing their thing!
     
  4. Nosybear

    Nosybear Well-Known Member

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    Agreed, three points doesn't make a difference and if it really worries you, add a bit of water! The difference 3 points makes is 15 total gravity points (3 points on your hydrometer multiplied by 5 gallons). At 1.061, you have 305 total gravity points (61 x 5). Adding water doesn't change this, so you can add a quart of water to your fermenter (if it will hold it). You now have 5.25 gallons of beer. Divide the 305 gravity points - the amount of sugar in the wort hasn't changed - by the new volume, 5.25 gallons and your new OG is 1.058 points. Or if you want to use ratio calculations, 61*5=58*X, 61/58*5=5.259, or an additional quart of water.
     
  5. DufrenesPartyof2

    DufrenesPartyof2 New Member

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    Dude...
    When grains are touching water the temperature is crucial. It can be the difference between too thick, too thin, not enough flavor, too dry, not enough fermentables. I can't stress enough how important keeping a extra watchful eye on a thermometer that has its temperature reading end in the grist, is. That's my two cents, you take if for what you want.
    Signing off, #1
     
  6. The Brew Mentor

    The Brew Mentor Well-Known Member

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    OP,
    As you stated, this is an Extract with steeping grains kit.
    Unless you're doing a mini mash with some base grains, you're not converting any starches into sugar.
    The Extract will give you a predetermined amount of fermentable sugars and that is what the OG on the Kit is based on.
    I think you're perception is that your getting more fermentables from the steeping grains and the pumpkin. You're not.
    The OG difference can be off from the kits prediction for a number of reasons( water volume, temp of sample, how well you rinsed the cans, not mixed well, etc). Make no mistake about it though, if you added all the extracts and fill your fermentor to the five gallon mark, you will hit the correct amount of fermentable sugars for the kit.
    Mashing grains in an all grain or mini mash is when you want to start tracking your efficiency. If your doing kits, you can just rely on what the kit maker says as being accurate.
    Hope this helps.
    Brian
     
  7. BrewHop

    BrewHop New Member

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    Hey Mentor,

    I agree with what you have said but there is another thread regarding his pumpkin recipe which gives some more info.

    I believe he actually steeped the pumpkin with some 6 row at about 155F to try to get any pumpkin sugars to convert. Thus, I believe at that temp it would convert some pumpkin if not it's own sugars into fermentables. It seems like he did some version of a mini-mash, but I could be wrong about what he did too... :D
     
  8. MrBIP

    MrBIP Active Member

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    You are right, and after I thought about it, seems that pumpkin surely had to account for those few points in OG. Too bad that can't be included somehow in the recipe calculator.

    So far, it's doing what it suppose to do, been in primary since Sunday afternoon and appears now to be coming to end. I'm out of town this weekend, so think I'll just leave it sit and hope to transfer to secondary Monday-Tuesday.
     
  9. BrewHop

    BrewHop New Member

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    Bip,

    Like others said before, there are really a lot of factors in what OG you get even if it shows that it should be a certain number in you recipe calculator. I almost never hit the numbers in the recipe and am pretty consistencly a few points under.

    I would leave the beer in primary for about 2 to 4 weeks personally.
     
  10. LarryBrewer

    LarryBrewer Active Member

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    Sounds like you could fix that by lowering your efficiency estimate on the recipe a couple points!

    Consistency is what matters, not how high your efficiency is. In fact, the way the system looks at efficiency is going to be expanded dramatically in the next release. We are also going to have a blog post on what the different types of efficiency are, and how they are arrived at.
     
  11. MrBIP

    MrBIP Active Member

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    well, i can see from reading message boards, Papazian, playing with brew calculators, reading about / researching ingredients, etc. that I'm going to get caught up in this.

    .............. and I cracked a bud light for the first time in a long time during this baseball game and after I finish choking it down I'm going to have a pop or bottle of water and wait patiently for my own brew to finish so can drink something good. :D
     
  12. MrBIP

    MrBIP Active Member

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    HA! I figured it out.
    I was using defaults for LME and DME; when I look up and plug in the actual values for the products that came with this kit, the recipe calculator gives me a 1.061 ... spot on to what I actually got. (I know, I know, it was close enough, but now that I see I can put in "custom" numbers, I'll just use what the product is actually telling me rather than the defaults).

    .... doesn't work with my second batch that calculates 1.069, but read 1.076 when I got it in the fermenter, but no worries; it smelled and tasted awesome.

    (I'm going to have to belly up and by the membership here; the recipe calculator is great and forum has been very helpful).
     

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