Brewhouse Efficiency Calculated vs. beersmith

[bbump22]

I have moved on from Extract brewing into Partial Mash brewing and have done several batches now. The first few, I didn't measure my pre-boil gravity as I was using recipes from BYO and it didn't mention anything about pre-boil gravity...I would still hit the Target OG within a few points. Recently, I have been using the trial version of Beersmith to generate my own recipes. The first batch I brewed, I successfuly hit the target OG beersmith estimated assuming the default brewhouse efficiency of 75%...honestly, I think I just got lucky.

On my next batch, I generated a recipe in the same manner (assuming 75% Brewhouse Efficiency), but missed my target OG by about 12 points...After entering in my pre-boil gravity, pre-boil volume, batch volume and actual OG measurements, beersmiith spit out a brewhouse efficiency of 52%...When I did the calculations by hand, I calculated an Extract Efficiency of 74% and Brewhouse efficiency of 68%. So my question is why would Beersmith give me an efficiency % so much lower than what I calculated by hand if I used the same numbers I plugged into Beersmith? I am sure it's probably something I am overlooking, but I can't quite figure it out. I've spent the last 2 days at work searching the forum's but couldn't find anything that gave me a clear reason as to why there would be such a variance.

Below is the grain bill, measurements, and calculations I generated on my own...If one of you experts could help me out so I can get better brewhouse efficiency allowing me to use beersmith to generate a recipe I would be very greatful!

Target OG based on 75% brewhouse efficiency 1.065
Actual Original Gravity 1.053
Est. FG 1.013 - 1.018

Grain Bill: Lbs
US 2-Row 4.5
Crystal 60L 1.5
Carapils 0.5
Rye 0.75
Liquid Malt Extract 2.5
Extra Light Dry Extract 1 (Added for the last 15 minutes of the Boil)


Calculate Estimated Original Gravity
Grain Malt PPG Malt Lbs Total Available Gravity Points
US 2-Row 37 4.5 166.5
Crystal 60L 34 1.5 51
Carapils 33 0.5 16.5
Rye 29 0.75 21.75
Liquid Malt Extract 36 2.5 90
Extra Light Dry Extract 44 1 44
10.75 389.75

Original Gravity Calculation (SGP) assuming 75% Brewhouse Efficiency
=((4.5*37*0.75)/5) + ((1.5*34*0.75)/5) + ((0.5*33*0.75)/5) + ((0.75*29*0.75)/5) + ((2.5*36*1)/5) + ((1*44*1)/5)
65.1625
SGP = 1.065


Caclulate Extract Efficiency

TGP (Total Available Gravity Points)
Grain Malt PPG Malt Lbs Total Available Gravity Points
US 2-Row 37 4.5 166.5
Crystal 60L 34 1.5 51
Carapils 33 0.5 16.5
Rye 29 0.75 21.75
Liquid Malt Extract 36 2.5 90
9.75 345.75

Maximum Specific Gravity
=TGP/Collected Volume in Gallons
=(345.75/3.5) 98.78571429 1.099

Extract Efficiency (EE) 74%
=(Measured SG/Maximum Specific Gravity in Points) * 100
=(73/99)*100 0.737373737


Calculate Brewhouse Efficiency
Grain Malt PPG Malt Lbs Total Available Gravity Points
US 2-Row 37 4.5 166.5
Crystal 60L 34 1.5 51
Carapils 33 0.5 16.5
Rye 29 0.75 21.75
Liquid Malt Extract 36 2.5 90
Extra Light Dry Extract 44 1 44
10.75 389.75

Maximum Specific Gravity
=TGP/Collected Volume in Gallons
=(385.75/5) 77.95 1.078

Brewhouse Efficiency 68%
=(Measured SG/Maximum Specific Gravity in Points) * 100
=(53/78)*100 0.679487179

So that's what I did to figure out Extract Efficiency and Brewhouse efficiency. I mainly want to know how to improve efficiency or at least make it consistent so that I can develop recipes and hit my target OG or at least within a few points. Again, thanks for any help you can offer!

 

[HairyDogBrewing]

You didn't describe your mash or sparge method.
You did a mash, not just steep, right?
Also, the grain crush has a big effect on efficiency.
How accurate are your scales, hydrometer, thermometer, bucket, etc?

 

[bbump22]

my bad, I should have provided more background info...but yea, i did measure my volume...I had collected 3.5 gallons at pre-boil. After a 60 minute boil, I had 3 gallons remaining in my kettle at which point I added 2 gallons of bottled water to the fermenter, the added the remaining 3 gallons to the fermenter bringing the total batch volume up to 5 gallons.

Also, I mashed with 10 quarts for 60 minutes with a step temp at 154, losing 2 degrees over the course of the mash. Then I batch sparged with 7 quarts with a step temp of 165. (Added water at 186 and then stirred gently and let it sit for another 15 before draining).

I calibrated my hydrometer and thermometer and used measurements on my kettle to measure the pre-boil volume. I took a sample directly from the kettle after incorporating the 2.5 # of LME and adjusted my hydrometer reading for temperature.

I crushed my own grain at my LHBS using their mills and do not believe it to be the problem as my Extract Efficiency is in the 70's...

Let me know if you need any other background info and thanks for looking into this with me.

 

[HairyDogBrewing]

BTW, Welcome to HBT!

I think your brewhouse efficiency (68%) is the weighted average of the grain efficiency (52%) and the LME/DME efficiency (always 100%).
Efficiency numbers only apply to grains, since there are no losses when adding LME/DME.

I'm not sure why your efficiency is as low as it is.
It may be the grain bill or the crush or your lauter tun.
Efficiency is discussed at great length elsewhere on the site.

One common mistake is not stirring in the top-off water before taking the sample.
Also, you should cool samples to below 80F, since they can be off at high temperatures - even after applying the correction for temperature.

Hope this helps.
Cheers!