Og not what SG indicates

[timos]

Hi all,

I cant figure out why my OG was so high when I calculated a low SG.

7.75 lbs of grains in a partial mash.
I measured an SG of 1.018 @ 130° in a volume of 4.5 gallons
With temp. correction that should give me a brew house efficiency of 46%

After adding 8.6 #s extracts and boiling 1 hour
I got an O.G. reading of 1.11

I dont know how the gravity is so high. Plugging in the numbers even a 100% brewhouse efficiency does not get me quite that high. What am I doing wrong with the numbers?

TIA,
Tim Johnson

 

[agrazela]

You don't say what grains you used (nor how you mashed them), but assuming 7.75# of base 2-row or somesuch and a 4.5gal volume, your reading of 1.018@130F, corrected via online calculator to say 1.030@60F, does yield ~48% BE. So I believe that. That's pretty poor efficiency, and IMO needs work...but I digress!

You don't say what extracts you used (type, dry or liquid) nor your final volume, but assuming 8.6# of a basic light LME (which adds volume, probably about 0.75gal), then boiling for an hour and finishing with say 4 to 4.25 gal, I calculate an OG of ~1.11. So I believe that, too.

I don't see a problem with the numbers.

 

[Yooper]

The SG reading of over 90 degrees, even with correction tables, is wildly inaccurate. That reading of 1.018 is worthless. The sample must be cooled to under 100 degrees, then a reading taken and the correction taken into account.

Was your extract liquid or dry? If liquid, in 5 gallons, 8.6 pounds of extract would give you 1.060. If dry, it would give you 1.072. Add that to the runnings from 7.75 pounds of grains, and that would explain the 1.100!

 

[RM-MN]

If you did a partial boil and topped up the fermenter with water to the proper amount the reading you got would be from incomplete mixing of the concentrated wort with the top off water. You simply got mostly concentrated wort for you hydrometer sample.

 

[timos]

I used 6#s MO and 1# of specialty grains and .25 each of flaked barley, oats, and wheat.
6.6 #s LME and 2 lbs of DME (3 cups used in the 1 gallon starter)
Nottingham yeast btw.
The volume was a little over 4.5 gallons after the boil, I then pitched the whole gallon of starter minus a bit of trub on bottom.
Then I took a sample to measure the OG.
I think I must have gotten a better efficiency than I thought. I did not realize I needed to cool it below 100° so will do that in the future.
The siphon did pull from the bottom third of carboy so It is also possible It was not mixed up well.

I had krausen in 2 hours and a wicked fermentation by 18 hours. Now it is relatively calm.

I am trying to replicate the flavor profile of my familys Glögg recipe in a spiced Christmas sipper for next winter.

Thanks again for the comments,
tim