Brewhouse Efficiency Question - Veterans Help!

[rhern053]

2nd all-grain brewed Sunday. This is the first time I'm taking brewhouse efficiency into account. I think I'm doing this right, but my result seems wrong.


Ingredient............Amount % When
US 2-Row Malt......6.00 lb 64.9 % In Mash/Steeped
US Carapils Malt....1.00 lb 10.8 % In Mash/Steeped
UK Light Crystal.....0.50 lb 5.4 % In Mash/Steeped
UK Rolled Oats.......0.50 lb 5.4 % In Mash/Steeped
US Chocolate Malt...0.25 lb 2.7 % In Mash/Steeped
Sugar - Honey........1.00 lb 10.8 % End Of Boil

5.75 gallon in the fermenter when I took the gravity reading (@ 60 degrees F) and I got an OG of 1.058. According to Beer Alchemy, at a 75% efficiency I should have only had a 1.045. I changed the efficiency slowly (80%, then 85%, then 90%, etc.) to see at what efficiency I was running at to get such a high OG until I got the gravity to say 1.058. But I was only able to raise it to 1.058 when my efficiency was at 99%.

Now I highly doubt my efficiency is such. What could I be missing?

 

[njschmidt]

Maybe the wort wasn't mixed well, leading to a heavier sample drawn for the hydrometer? Does the 5.75 gallons include any top-off water? If so you might not have mixed it well with the wort, getting an inaccurate denominator for dividing the potential gravity points.

For example, if you added 0.75 gallons of water but drew your sample from wort that hadn't had time to mix yet, the potential gravity of the 5 gallons would be around 1068 and your efficiency would be 85%.

 

[rhern053]

I think it was mixed well. I took a reading before the boil and with some calculations got to around 1.058 OG, then again after I chilled it and still got 1.058.

No top-off water.

 

[njschmidt]

If your SG was 1058 both before the boil and after, then something is definitely inaccurate in the measuring area. I would be sure to calibrate the hydrometer and always make sure to have an accurate sample to measure from.

 

[rhern053]

The SG after the boil was 1.058. The reason I say it was 1.058 before the boil is because I took the gravity, and corrected it for temperature and one hour's worth of boil-off. These calculations resulted in an SG of around 1.058, roughly.

 

[ThePearsonFam]

The SG after the boil was 1.058. The reason I say it was 1.058 before the boil is because I took the gravity, and corrected it for temperature and one hour's worth of boil-off. These calculations resulted in an SG of around 1.058, roughly.

So your pre-boil (measured) gravity was lower than 1058 and had a larger volume. You simply adjusted for the desired final volume to determine your expected post-boil OG (basically trying to estimate what your OG should be based on pre-boil numbers)?

 

[rhern053]

Yes exactly. I still took a post boil reading at 60 degrees.