Another Efficiency Question

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37OliveStBrews

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Hi Folks,
I have John Palmers book How To Brew and just completed by second all grain batch. I am interested in figuring out my efficiency but I am unsure how to calculate it. Do I need software to be able to know the potential of my grain bill?
I had a preboil gravity reading of 1.034 with 7.8 gallons of water used in both mash and sparge water. My post boil gravity reading was 1.057. My grain bill was:
8 lb Rahr 2-row pale
.75 lb Simpsons Chocolate Malt
.25 lb Simpsons Extra Dark Crystal
.25 lb Weyermann Dehusked Carafa III
Boil Additions:
1 oz Cluster at 60
1 lb Lactose at 60
.5 oz Cluster at 30

This ended up being a 90 minute boil after I realized I had too much wort at 60 minute.
Would love to know if there is a simple equation for figuring efficiency.
 
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37OliveStBrews

37OliveStBrews

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Thanks Bassbone,
I think the problem with a lot of the online calculators is that they don't always have the ingredient that is part of the grain bill. The one you quoted for example doesn't have Rahr 2-row or chocolate malt.

I am anxiously awaiting Beersmith to release their mac version since that is the operating system/computer I use. I tried Beer Alchemy's free demo but wasn't blown away.

I appreciate your post reply.
 

bassbone

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Rahr is an American 2 row. Simpsons chocolate is a Brit chocolate malt (am 2 row and brit chocolate are both on that calculator).

It might not be exactly the correct numbers for the malts you used, but it will be very close. And honestly, even if they had Rahr 2 row listed that would not necessarily match the Rahr malt you used (which is why you need malt lot analysis sheets if you want to be 100% accurate).
 
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37OliveStBrews

37OliveStBrews

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Basstone,
Thanks again for the explanation. According to that calculator I hit 93% efficiency. Wow.
 

bassbone

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Did you end up with 5 gallons post boil? I get 84.2% on tasty brew and 85.72% in beersmith with your numbers assuming 5 gallons. (both are very good numbers)

5.5 gallons bumps it up to 94%.

Are you sure about the gravity and volume readings?
 
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37OliveStBrews

37OliveStBrews

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Yeah turned into 5.5 gallons. The sg was take with both refractometer and verified with hydrometer.
 

ThePearsonFam

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No need for software to determine potential yield from your grain (but it does simplify the process).
2-row = 37 PPG, so (37PPG * 8lbs.) / 7.8gal (pre boil volume) = 37.95 possible points
Chocolate Malt = 34 PPG, so (34PPG * .75lbs) / 7.8gal = 3.27 possible points
Crystal = 33 PPG, so (33*.25)/7.8 = 1.06 poss pts.
Carafa = 32 PPG, so (32*.25)/7.8 = 1.03 poss pts.

Add 'em up... 43.3 possible points. That's the potential yield of you grains (as points per gallon (PPG)).

You measured 34 points (1034). Divide 'em out... 34 measured points/43.3 possible points = .785 (multiply by 100 to get your %) = 78.5% efficiency from the mash. That's the simple math to determine your mash efficiency.

I think that answers your question. I have a question though...
Was your goal to get a 5 gallon batch or an OG of 1057?
 
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37OliveStBrews

37OliveStBrews

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ThePearsonFam,
Thank you! I enjoyed how you spelled that out. Trait of a good teacher. My goal was to get down to a 5-5.5 gallon batch. When I hit the 60 minute boil mark I still had 6 plus gallons so i let it boil another 30 minutes or so. So to answer your question it was more about the quantity than it was the gravity. I was happy to end up with the gravity given that the recipe said its OG was 1.051.
 

ThePearsonFam

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ok...

5.5 gallons (what you ended up with) * 57 (measured points - 1057) = 313.5

take 313.5 and divide it by the amount you had after one hour (6 gallons).

313.5/6 = 52... so, if you had stopped after one hour and collected 6 gallons, then your OG would've been 1052. Not bad since your target was 1051...

So, for future reference, you can work that math backwards from your pre-boil volume.

say you collect 7gal of 1040 wort and you want to hit 1050, 7*40=280. 280/50=5.6gal target post boil volume.

You have a couple options...
1) collect the bigger volume to hit your intended OG (and, ugh, dump the rest)
2) collect the bigger volume, boil until you hit you intended volume (which you did and didn't worry bout the OG)
3) collect the correct initial volume to boil down to your intended OG and post-boil volume (and do something else with the rest of your collected wort, like parti-gyle)
 

bassbone

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Pearsonfam,

You are calculating a different efficiency than i am. You are looking at mash efficiency (efficiency into boiler) i am looking at brewhouse efficiency (efficiency into ferment tank). Generally, if a recipe posted online says "calculated for 75% efficiency" that is talking about brewhouse efficiency.

If you divide by 5.5 gallons instead of 7.8 and then use the final gravity instead of 1.034 at the end, that will make up the difference (the PPG's you are using are also a bit different than the ones tastybrew uses, which accounts for the rest of the difference).
 

ThePearsonFam

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@bass.... yup, surely true. great point.

@37... no problem. Did you managed to find an answer to your question in there?
 

Bigscience

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Hi Folks,
II had a preboil gravity reading of 1.034 with 7.8 gallons of water used in both mash and sparge water. My post boil gravity reading was 1.057.
I think the "7.8 gallons of water used in both mash and sparge water" may be an issue. Did you measure 7.8 in the kettle? There is loss to the grain and to the pot itself so water in does not equal wort out. This would leave you with lower volume=less total points=lower extraction efficiency.
 
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