Author Topic: Missed OG  (Read 1465 times)

Offline gcam333

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Missed OG
« on: April 26, 2010, 07:24:36 PM »
I brewed my second batch this weekend. Decided to semi come up with a recipe that I would call a big IPA. I used the calculator on tastybrew. I tried to be very precise even used digital scales and a stopwatch . According to the calculator my OG should have been 1.066, Actual was 1.073. Is this within the normal margin of error? I also made a starter out of SA-05 because of the high OG and have had a good strong fermentation for 36 hrs. I'm pretty sure I have enough yeast to finish it off.
I'm learning slowly.

Offline tygo

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Re: Missed OG
« Reply #1 on: April 26, 2010, 07:34:28 PM »
I'd say that you underestimated your efficiency a bit but we'd need more info to be able to help you figure out what happened.  Post the recipe and your assumed efficiency.
Clint
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On Tap: Lucifer's Hammer Golden Strong Ale, Dopplebock, Old Fuzzynut's Ale

Offline gcam333

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Re: Missed OG
« Reply #2 on: April 26, 2010, 07:52:20 PM »
Boil Vloume 3.5
Batch size 5.25

5.68 lb DME
2.2 lb LME
1.25 lb Crystal 60
.25 Special B

1.0 Hallertau Tradtion  @ 50
1.0 Fuggles @ 30
1.0 Cascade @ 20
!.0 Cascade @10
1.0 Cascade @ 2

Target OG was 1.066    Actual was 1.073   assumed efficiency was 75%
Target FG was 1.017
58 IBU

Offline abraxas

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Re: Missed OG
« Reply #3 on: April 26, 2010, 07:57:36 PM »
Two things...

Under-pitching a little isn't going to make too much of a difference.  Don't worry about it.

That being said, it probably wasn't necessary to make a starter with the S-05.  Jamil's calc: http://www.mrmalty.com/calc/calc.html  lists a 263 billion yeast cell count as optimal for a 1.073 beer which equates to (1.3) 11.5 gram packets.  I am sure whatever size starter you made put you well into that category.  Had you just pitched the packet, you would have been a little light which might have resulted in a few more esters but for your second brew there's probably a number of other more important things you should be worries about.

As to why you have a high OG, I'd guess temperature correction and hygrometer calibration could be one reason.   Double check your hygrometer in water and use a correction table: http://www.ebrew.com/primarynews/ct_hydrometer_temp_correction.htm
My last hygrometer read high by .002 points for some reason, probably just because it was a cheap one not checked closely at the factory.

Also double check your final volume.  You may have boiled off more than you were expecting leaving you with less liquid and a higher final resultant gravity.  This is easily remedied by adding sterile makeup water.
« Last Edit: April 27, 2010, 11:15:56 AM by abraxas »

Offline tygo

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Re: Missed OG
« Reply #4 on: April 27, 2010, 03:38:27 AM »
Boil Vloume 3.5
Batch size 5.25

Since you topped off after boiling it could be that the beer was not evening mixed when you took your sample.  But that usually leads to a lower OG reading when topping off so what abraxas said is more likely.  Either an inaccurate hydrometer or your volumes were a little off.
Clint
Wort Hogs

Fermenting: Wit
On Tap: Lucifer's Hammer Golden Strong Ale, Dopplebock, Old Fuzzynut's Ale

Offline gcam333

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Re: Missed OG
« Reply #5 on: April 27, 2010, 04:23:05 AM »
I topped off to my graduations that I have marked on my fermentor. I have 1 gal increments 1-5 and then a mark at 5.25 gal.
I then Areated the wort by pouring back and forth between 2 sterile buckets before checking the OG. It should have been thoroughly mixed. I will check my hydrometer.

Offline gcam333

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Re: Missed OG
« Reply #6 on: April 27, 2010, 04:28:40 AM »
Hydrometer was accurate to within .001

Offline tygo

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Re: Missed OG
« Reply #7 on: April 27, 2010, 06:22:14 AM »
Ok, couple of other possibilities:

1)  Are you sure that the potential gravity of the extracts you used were exactly the same as what tastybrew is assuming?
2)  What are you fermenting in?  Did you put the volume graduations on it yourself or are you relying on say, the factory markings on a bucket (which can be inaccurate)?

Since this is an extract brew with specialty grains only efficiency isn't a factor.  Since you've confirmed that your hydrometer is accurate that kind of narrows it down.  Either there were more fermentables added than planned or less volume.
« Last Edit: April 27, 2010, 06:31:06 AM by tygo »
Clint
Wort Hogs

Fermenting: Wit
On Tap: Lucifer's Hammer Golden Strong Ale, Dopplebock, Old Fuzzynut's Ale

Offline denny

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Re: Missed OG
« Reply #8 on: April 27, 2010, 09:08:03 AM »
Did you end up with the 5.25 gal. your recipe calls for?  If you were short on volume, the OG could be higher.
Life begins at 60.....1.060, that is!

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Offline bluesman

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Re: Missed OG
« Reply #9 on: April 27, 2010, 09:51:21 AM »
From my experiences the OG must be targeted through extract potential and liquid volume which can be assessed through specific gravity. More often than not it comes down to an adjustment in your water either boiling more or adding more water. This assumes a relatively good efficiency.
Ron Price

Offline mikeypedersen

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Re: Missed OG
« Reply #10 on: April 27, 2010, 10:22:48 AM »
Did you end up with the 5.25 gal. your recipe calls for?  If you were short on volume, the OG could be higher.
By my calculations being half a gallon short accounts for your difference in OG.

Offline gcam333

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Re: Missed OG
« Reply #11 on: April 27, 2010, 01:26:09 PM »
I marked the bucket myself. I actually overshot the 5.25 mark when I topped off with water .  I used a graudated pitcher of the better half's, added 1gallon at a time and made my marks. I guess the pitcher possibly eas not very accurate. Once I rack this over to the secondary, I think that i will repeat the excercise by weight to get more accurate graduations.  Now that I think about it, my first batch came up a few bottles short. I did have some waste but not that much.  That could well be the problem.

When the target OG was 1.066 the target FG was 1.017  Should I now expect 1.023 ????

Offline denny

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Re: Missed OG
« Reply #12 on: April 27, 2010, 02:32:58 PM »
Not necessarily.  There's no really accurate way to predict FG.  Unless you've brewed the same batch the same way a number of times, it's no more than a guesstimate.  Give it 2-3 weeks in primary and take a gravity reading.
Life begins at 60.....1.060, that is!

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Offline gcam333

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Re: Missed OG
« Reply #13 on: April 27, 2010, 03:52:22 PM »
Thanks again Denny. Thats what I'll do