Efficiency Lower Than Expected - Expert Advice Wanted

[VApatriot]

On Saturday I brewed an all grain batch and ended up with a lower OG than expected. The recipe I used is below as is a pic of my set-up. I have been using this set-up for years now and have hit the OG of other recipes right on the mark in the past, but not on Saturday.

I expected to hit the target OG as listed below but only hit the actual pre-boil and OG also listed below. I do use a false bottom in my mash kettle which requires 1 1/4 gallons of foundation water to cover it. Due to the size of my BK I can realistically only collect 6.5 gallons of wort, any more than that and I will definitely have a boil over. Mash temp, mash time, sparge temp, and sparge time are also listed below.

So any suggestions of what I could have done better would be greatly appreciated. Thanks in advance for your help.

Recipe:

Rob’s Centennial – Citra Blonde Ale

Recipe Type: All Grain
Yeast: WLP-060
Yeast Starter: Yes
Batch Size (Gallons): 5.0
Target Original Gravity: 1.062
Target Final Gravity: 1.012
Est. IBU: 34.74
Est. Color: 4.37
Boiling Time (Minutes): 60
Primary Fermentation (# of Days & Temp): 9 days @ 64 degrees F
Secondary Fermentation (# of Days & Temp): 7 days @ 64 degrees F

Batch Size: 5.00 gal
Boil Size: 6.50 gal
Actual Preboil OG: 1.046 SG
Actual OG: 1.056 SG
Actual FG: TBD
Boil Time: 60 Minutes

Ingredients

Grains:
9.50 lb. Pale Malt (2 Row) US (2.0 SRM)
0.75 lb. Cara-Pils/Dextrine (2.0 SRM)
0.25 lb. Caramel/Crystal Malt - 10L (10.0 SRM)
0.75 lb. Vienna Malt (3.5 SRM)

Hops:
0.50 oz. Centennial [8.50%] (60 min)
0.50 oz. Centennial [8.50%] (20 min)
0.50 oz. Citra [13.2%] (7 min)
0.50 oz. Citra [13.2%] (0 min)

Yeast:
WLP-060 American Ale Yeast Blend

Notes:
- Foundation water (to cover false bottom) – use 1 ¼ gallon
- Mash water - use 1 1/4 quarts per pound of grain = 3 ½ gallons, 2 oz.
- Sparge water - use 1 1/2 quarts per pound = 4 gallons, 3 ½ cups

- Mash at 150 degrees F. for 60 minutes.
- Mash out at 168 degrees F. for 10 minutes
- Sparge water temp – 168.0 degrees F.
- Sparge for 60 minutes


I used 5.2 ph Stabilizer in the mash and sparge water per the directions, the gap on my Barley Crusher is ~0.039", grains were less than 2 weeks old, crushed on Saturday morning before brewing. The only 2 variables that were not under my control were A) weighing of the grain bill by the guy at my LHBS, and B) the age of the grains.

Pic of my set-up except the boil kettle which is the same type as the HLT and mash kettle.

 

[TheMadKing]

Did you measure your preboil and post boil volumes accurately?

IME efficiency issues are usually volume related more often than conversion or extraction related.

I had a very sneaky leak in my immersion chiller inlet that added .25 gallons to 2 batches before I even noticed it running down the underside of the copper tubing into the boil kettle during chilling.

EDIT: the math doesn't work on your gravity readings unless your volumes were off.

46gravity points x 6.5gallons = 299 ppg

299ppg/5gallons = 60 gravity points aka 1.060 OG

So either you didn't boil off as much as you thought, you gained water during the boil, or your preboil volume was off

 

[cshamilton]

If your crush is good, and your volumes are good, double check your thermometer calibration. If your pre-boil gravity is low, you can always boil for 30-60 min and collect more wort. I have to do that for big beers.

 

[VApatriot]

MadKing - no, my volume measurements are very accurate and my hydrometer is also calibrated correctly. I did let my pre-boil and OG samples sit until Sunday before I took my readings (always at 60 deg. F btw)

cshamilton - I used both the kettle thermometers and my Thermapen which is very accurate, so I don't think that either of those are suspect.

 

[TheMadKing]

MadKing - no, my volume measurements are very accurate and my hydrometer is also calibrated correctly. I did let my pre-boil and OG samples sit until Sunday before I took my readings (always at 60 deg. F btw)

cshamilton - I used both the kettle thermometers and my Thermapen which is very accurate, so I don't think that either of those are suspect.

Do you have your precise preboil and post boil volumes for us to see?

I used 6.5 gallons preboil in my math above and 5 gallons post boil, but since the math doesn't work, one of those two volumes must be wrong.