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First All Grain Brew - High pre-boil gravity

Discussion in 'Beginners Beer Brewing Forum' started by Leggoma, Aug 10, 2014.

 

  1. #1
    Leggoma

    Well-Known Member

    Posted Aug 10, 2014
    So my first all grain brew is underway. After mashing, i took a pre-boil sample and stuck it in the freezer until its temp dropped to 70 degrees. When i took my gravity reading, it came in at 1.056. The estimated preboil gravity was supposed to be 1.044. I'm at a 90% efficiency, which cannot be right.

    What could be the issue? Did I screw something up with my batch sparge? Possibly a broken hydrometer?

    I'll get my OG here in about an hour. We will see.
     
  2. #2
    Leggoma

    Well-Known Member

    Posted Aug 10, 2014
    Well, my OG was the same reading as my pre-boil, so I'm chalking it up to a bad hydrometer. I'll have to invest in a refractometer. It looks like I may only have 4-4.5 gallons in my carboy, so i can expect a low volume batch. Maybe the American Wheat wasn't a good first all grain brew.

    I'm a bit disappointed with the brew day. Two positive take-aways, my equipment worked out nicely and I'll have some sort of beer in 6-8 weeks. No clue what the ABV will be and how good it will taste, but I'm sure it will be drinkable. Also, I'm a bit disappointed with the Homebrew Supply stores local to the Salt Lake City, UT area.
     
  3. #3
    MindenMan

    Well-Known Member

    Posted Aug 11, 2014
    Why do you say you have a bad hydrometer? Did you calibrate it with distilled water @ 60* F? I did the math, and if your batch was supposed to be 5.5 gallons @1.044, and you ended up with 4.25 gallons, your predicted O.G. should be 1.055. Your equipment isn't broken, you are where you are supposed to be, so RAHAHB. JM $0.02
     
  4. #4
    Leggoma

    Well-Known Member

    Posted Aug 11, 2014
    Is it not strange that the pre-boil gravity reading was basically the same as the OG? I guess I just assumed it would change rather than stay basically the same. At any rate, that makes me feel better. I didn't calibrate it at 60 degrees, I was going to do that before throwing out the hydrometer just to make sure.

    I can sleep well at night.
     
  5. #5
    chickypad

    lupulin shift victim  

    Posted Aug 11, 2014
    If you boiled off water the readings couldn't have been the same. My guess is your pre-boil wort was not well mixed and maybe you got a higher percentage of first runnings in your measurement.
     
  6. #6
    Qhrumphf

    Stay Rude, Stay Rebel, Stay SHARP  

    Posted Aug 11, 2014
    This.

    First runnings are usually 1.070 or so, and at the very end of the sparge they can be much, much lower than that. And just like partial boiled wort and top off water, they can stratify and screw up the reading. It's not as intense a stratification as it is with wort and top off, but it's there.

    So make sure you're stirring the crap out of it before taking a reading, and then assume that it's a ballpark figure, not an exact. I usually figure that my actual OG will be +/- 3 or 4 points from what I calculate based on pre-boil. Basically innacurate enough that I don't even bother any more unless I'm doing a VERY high gravity beer.
     
  7. #7
    Leggoma

    Well-Known Member

    Posted Aug 11, 2014

    The recipe I had seemed to call for smaller volumes of water that made sense to me. That being said, I did end up adding more water to the mash tun than called for, the last gallon coming out of the batch sparge was VERY light. I'm not sure if there are denser pockets of sugars that settle lower in the wort, but I was using my bottling bucket to catch my runnings and I used the spigot at the bottom of the bucket to get my measuring wort. So everything you said makes sense.

    I'll mark it up as a lesson learned.
     
  8. #8
    MindenMan

    Well-Known Member

    Posted Aug 11, 2014
    If no one has told you hydrometers are not very accurate when the liquid tested contains alcohol, now you know.
     
  9. #9
    chickypad

    lupulin shift victim  

    Posted Aug 11, 2014
    You mean refractometers. Anyway, these are all pre fermentation readings - there's no alcohol so a refractometer without correction would be fine too.
     
  10. #10
    Qhrumphf

    Stay Rude, Stay Rebel, Stay SHARP  

    Posted Aug 11, 2014
    Not sure how that's relevant since we're talking about pre-boil and OG readings before fermentation.

    Unless you mean the liquid inside the person using the hydrometer contains alcohol...
     
    Staylow likes this.
  11. #11
    chickypad

    lupulin shift victim  

    Posted Aug 11, 2014
    :D
    I'm sure that's lead to countless false readings!
     
  12. #12
    MindenMan

    Well-Known Member

    Posted Aug 11, 2014
    Okay, you got me, I goofed. I did not mean hydrometer...
     
  13. #13
    pvault98

    Well-Known Member

    Posted Aug 11, 2014
    Don't worry too much about it. My suggestions are get yourself a refractometer, and take copious notes and do it exactly the same and get a better sense of your system. It is going to take a handful of brews to get to know your system, but if you take good notes and pay attention to your process you will get it figured out.

    I know you want it to go perfect the first time around on your new AG setup, but as long as the beer taste pretty good you still come out ahead. The fact you are worried about Pre-boil vs OG is a good sign, just keep at it. For me, I took readings every 15 mins to get a good feel of my boil off rate as well as how my gravity changes throughout the boil. Now I build my recipe in beersmith and tweak what it tells me my numbers will be based on what I know will actually happen. I know exactly how much my volume is going to change and exactly what my gravity will beer because I took the time at the beginning to take good notes.

    Hang in there and each batch will keep getting better and you will know exactly what to expect in no time.
     
    Leggoma likes this.
  14. #14
    MindenMan

    Well-Known Member

    Posted Aug 11, 2014
    +1^^^ When I started brewing, I was allover the place, O.G., F.G., sparge methods, uncontrolled mashing and fermentation temperatures etc., you get the idea. It was beer, it wasn't great beer, but it was still beer. I still forget to take notes, and still regret when I don't (ADHD sucks). I will suggest, as close as is possible, do everything the same way every time, until you get some brews under your belt. That way, if something isn't quite right, you should know where to look to fix it.
     
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