Author Topic: Missed O.G. Question with Extract + Grains Recipe  (Read 1624 times)

Offline EThome

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Missed O.G. Question with Extract + Grains Recipe
« on: May 16, 2016, 10:02:16 PM »
I have been brewing only extract with grains recipes since I started several years ago. Have 30 batches done with the majority turning out really well. I haven't paid too much attention to the original gravity estimations that most recipes come with. Sometimes I get really close or right on - other times just close. I usually just measure O.G. and F.G. to get an idea of ABV at the end of it all. 

Over the weekend I brewed More Beer's Blonde Ale.
7lb Ultralight LME
8oz Crystal (steeped)
1 oz Willamette @ the full 60 min boil

The estimated O.G. is listed at 1.044 - 1.048.

My actual came in at  1.054 - both with a refractometer and the hydrometer.

I do full boils and there was 6.75 gallons in the kettle after adding the LME and 5 gallons in the fermenter at the end of the boil before pitching.

I'm not all that worried about the final product or the potential uptick in ABV, but anyone have an idea why the O.G.s would be so far apart?
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Offline blair.streit

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Re: Missed O.G. Question with Extract + Grains Recipe
« Reply #1 on: May 16, 2016, 10:55:52 PM »
I have been brewing only extract with grains recipes since I started several years ago. Have 30 batches done with the majority turning out really well. I haven't paid too much attention to the original gravity estimations that most recipes come with. Sometimes I get really close or right on - other times just close. I usually just measure O.G. and F.G. to get an idea of ABV at the end of it all. 

Over the weekend I brewed More Beer's Blonde Ale.
7lb Ultralight LME
8oz Crystal (steeped)
1 oz Willamette @ the full 60 min boil

The estimated O.G. is listed at 1.044 - 1.048.

My actual came in at  1.054 - both with a refractometer and the hydrometer.

I do full boils and there was 6.75 gallons in the kettle after adding the LME and 5 gallons in the fermenter at the end of the boil before pitching.

I'm not all that worried about the final product or the potential uptick in ABV, but anyone have an idea why the O.G.s would be so far apart?
With 7 pounds of LME and a few extra points from your Crystal, this calculator estimates a 1.040 OG on 6.75 gallons.

http://www.brewersfriend.com/allgrain-ogfg/

If you boiled that 6.75 gallons of 1.040 wort all the way down to 5.0 gallons you'd end up with 1.054. That's 26% boil-off rate which seems unlikely in a 60 minute boil.

I'm not sure if you left any liquid behind in the kettle or dumped the whole thing in, but you can use a calculator like this to see how small changes in volume would impact the OG.



Offline EThome

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Re: Missed O.G. Question with Extract + Grains Recipe
« Reply #2 on: May 17, 2016, 04:06:29 PM »
Thanks Blair.

Nope, didn't leave anything in the kettle. May have boiled a bit vigorously but not anything more than I have in the past. It was cool with a low dew point and humidity outside.

I'm going to start watching boil-off a little closer the next few batches, adjusting as necessary with boil rate, time, etc. Had I cut the boil off short of 60 minutes in this case once I hit 1.045 or so, would I expect any issues with not boiling the full 60 as typically recommended? Is boil time more important than the targeted S.G. or vice-versa?

Question using the calculator you pointed me to: until I make the move to all grain, is there an efficiency that should be "dialed in" for extract w/grain brews?
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Offline blair.streit

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Re: Missed O.G. Question with Extract + Grains Recipe
« Reply #3 on: May 17, 2016, 04:50:38 PM »
Thanks Blair.

Nope, didn't leave anything in the kettle. May have boiled a bit vigorously but not anything more than I have in the past. It was cool with a low dew point and humidity outside.

I'm going to start watching boil-off a little closer the next few batches, adjusting as necessary with boil rate, time, etc. Had I cut the boil off short of 60 minutes in this case once I hit 1.045 or so, would I expect any issues with not boiling the full 60 as typically recommended? Is boil time more important than the targeted S.G. or vice-versa?

I do recommend dialing this in a bit, as you will change the flavor of your beer by changing the intensity of the boil and/or changing the amount of time you boil. Humidity and other variables might force you to change this a bit in some conditions, but for the most part I can get mine pretty consistent now. Here's another calculator that just focuses on boiloff and dilution.

http://www.brewersfriend.com/dilution-and-boiloff-gravity-calculator/

Here's a great excerpt from an older thread on this topic:

One thing to keep in mind that for a given kettle and a consistent intensity of boil, you will boil off very close to the same volume per hour every time regardless of the actual volume of wort you start with.  In other words, if your boil off rate is one gallon per hour for your kettle (a pretty normal rate for a lot of folks) you will boil off that same amount whether you start with 5 gallons or 25 gallons in that kettle.

https://www.homebrewersassociation.org/forum/index.php?topic=3187.msg36031#msg36031


Question using the calculator you pointed me to: until I make the move to all grain, is there an efficiency that should be "dialed in" for extract w/grain brews?
You don't have to worry about extract efficiency with LME or DME, so this would only be applicable to the small amount of steeping grains you add. I'd guess 65% would be a conservative estimate here, but at such a small amount I think the OG difference between assuming 55% and 85% would be negligible.

Offline Saccharomyces

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Re: Missed O.G. Question with Extract + Grains Recipe
« Reply #4 on: May 23, 2016, 12:37:33 AM »
I am a huge proponent of brewers learning how to perform basic brewing mathematics instead of relying on software or brewing calculators. Knowing how to use brewing software and parrot the results is not the same thing as truly knowing how to brew.   None of the calculations needed in this case requires much in the way of mathematical maturity.

Five gallons of 1.054 wort has a total of 5 * 54 = 270 gravity points.   That figure divided by 7 yields 38.5 gravity points per pound per gallon (PPG), which is not out of the realm of possibility for LME because not all LMEs are concentrated to the same percentage of retained moisture (e.g., Alexander's was one of the least concentrated LMEs when I used liquid extract).  In the OP's case, it appears that the LME he received contained a higher solute content (less water) than the LME that was used to formulate the recipe (which is why one should list the actual LME used to formulate a recipe).  The upper bound for that recipe requires an LME with a PPG value of approximately 34 PPG (48 * 5 /  7 = 34.29 PPG), which is at the low-end of the LME PPG range.  I can obtain the low O.G. data point (1.044) using 7 pounds of grain in my brew house.

One of the reasons why I preferred to use DME when I was a 50% extract from grain/50% extract from DME brewer is because DME is fairly consistent across manufacturers (approximately 45 PPG).  The thing to watch out for with DME is that it is hygroscopic (draws moisture from the air).  Moisture lowers the PPG value for DME.