I need HBTs input on what could be wrong!

[Blindguardian]

Let me first say that I have learned ALOT from HBT members!!
I am looking for some input on what can be wrong with my set-up or procedures.

For the last 6 brews that I have done I have hit all my numbers except the FG and my efficiency has been coming in at around 103%. On the first batch that this started to happen I thought it was something I had done wrong or my equipment was off in calibration so from that point on I started to calibrate all my equipment the day before every brew ie. mash tun, kettle, hydrometer, thermometers and I also have been paying close attention to my boil off rates, everything seems to match up and I end up with my calculated post-boil volume.
I use BTP as my brewing software with a double batch sparge.

I did a Scottish 70/ yesterday and the SG was 1.031 and the FG was suppose to fall between 1.035 to 1.040. Well with hitting my numbers and boil off volume I ended up with a FG of 1.047.

here is the recipe:
Kettle volume: 7.49 gal (S.G. 1.031)
Boil Duration: 1 hr
Evaporation: .83 gal
Final Volume: 6.39 gal
Eff: 80%

OG: 1.036
Terminal Gravity: 1.010
ABV: 3.4 %
IBUs: 15.9

9-B Scottish Heavy 70/-

Ingredients:
5.9375 lb Maris Otter
0.5 lb Munich TYPE I
0.5 lb Honey Malt
15 oz 2-Row Caramel Malt 40L
0.25 lb 2-Row Caramel Malt 120L
3 oz Chocolate Malt
1.00 oz East Kent Goldings (5.0%) - added during boil, boiled 60.0 min
1.0 ea Fermentis US-05 Safale US-05

Schedule:
Ambient Air: 77.5 °F
Source Water: 80.4 °F
Elevation: 604.0 ft

00:13:49 Dough In - Liquor: 2.72 gal; Strike: 172.47 °F; Target: 158.3 °F
01:13:49 Rest - Rest: 60.0 min; Final: 158.0 °F
01:33:49 Double Batch Sparge - First runnings: 0.0 gal sparge @ 165.0 °F, 0.0 min; Sparge #1: 2.98 gal sparge @ 192.0 °F, 10.0 min; Sparge #2: 2.98 gal sparge @ 173.0 °F, 10.0 min; Total Runoff: 7.38 gal

Any thoughts about what I could be missing or what can be wrong?

I forgot to say that the hydrometer reading were cooled to 62* F and it is calibrated at 60* F.

 

[RedGlass]

I did a Scottish 70/ yesterday and the SG was 1.031 and the FG was suppose to fall between 1.035 to 1.040. Well with hitting my numbers and boil off volume I ended up with a FG of 1.047.

????

Either that was a type-o, or there's a problem with how you're reading your hydrometer. FG will be a lower number than OG. 1.031 wort will not turn in to 1.047 beer.

EDIT: Sorry, I just realized you're talking about pre-boil gravity vs. OG, not OG and FG.

 

[Bobby_M]

Are you sure you only boil down .83 gallons? How are you measuring the final volume? You certainly are not getting a real 103% efficiency. What are you doing with 6.39 gallons anyway?

 

[Blindguardian]

Are you sure you only boil down .83 gallons? How are you measuring the final volume? You certainly are not getting a real 103% efficiency. What are you doing with 6.39 gallons anyway?

I am measuring the final volume with a marked yard stick. I have it marked for every 1/4 gal of wort for my fermentation bucket on one side and the other side is marked for the same for my kettle. so I have to make a slight guess of the volume if it is a hair or so above my marks.

 

[dcp27]

If you started with 1.031 pre-boil at 7.49g (75% eff), there's no way you could have 1.047 at 6.39g (97% eff). Either your hydrometer is off, or your volume is. Have you checked it in water lately?

 

[DrDirt]

Stop brewing with pixie dust and things should correct themselves.

 

[JuanMoore]

I'm confused by the 0.83 gal boil-off, because you say the pre-boil volume was 7.49, and post was 6.39, which is 1.1 gal by my math. If your pre-boil SG was really 1.031, and you really did start with 7.49 gal and boil off a gallon, then math tells us that the post boil OG is 1.036. This means that either your hydrometer readings or volume measurements are way off.

How did you make the marks on your measuring stick? Maybe your high gravity first runnings weren't mixed well with your lower gravity sparge runnings when you took the pre-boil gravity, so you actually started with a higher SG than you thought.