General Category > Extract/Partial Mash Brewing

Partial Mash Extract Efficiency & Brewhouse Efficiency

(1/3) > >>

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!

tygo:
I'm having a little trouble following your calculations.  What was the volume you collected from the partial mash and what was your boil volume?

hokerer:

--- Quote from: tygo on March 09, 2010, 07:46:24 PM ---I'm having a little trouble following your calculations.  What was the volume you collected from the partial mash and what was your boil volume?

--- End quote ---

Yeah, did you actually measure your volumes?  It looks like you used 5 gallons in some of your calculations but did you actually measure it?  True volumes are critical to calculating efficiency.

bbump22:
Sorry fellas, 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.

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

a10t2:
When calculating your conversion efficiency, use only the grains, not the extract. Otherwise you'll get a different result every time the proportion of extract changes. I'm guessing that's why Beersmith is giving you different numbers.

Since you collected 3.5 gal at 1.073, that's 255.5 point-gal. Factoring out the extract:

(255.5 - (90 + 44))/(389.75 - (90 + 44)) = 0.475, about 48% efficiency. The discrepancy is probably due to slightly different potential extract figures.

Navigation

[0] Message Index

[#] Next page

Go to full version