Working Out Efficency In Biab

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stowaway

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Okay so im trying to work out the Efficency of my BIAB brew.
I think this last one was not very efficent.

here the forumula i have been given:

Efficiency(%) = OG X batch size X 100 / 307 / grain weight
WHERE AS:
OG = grain weight X (280/batch size)

I used : 5.5kg of Grain (5kg of Pale ale + 500gram of munich II)
Started the boil with 36litres.

ended up with 20litres.

After the Mash I was at 1.051

And After the boil and everything i measured at 1.053 (i left 2 litres of crap in the bottom, this measurement was taken from my fermenter)

OG = 5.5 X (280/20) = 77 (does batch size = what i ended up with?)
efficency = 77 x 20 x 100 /307 / 5.5 = 91.205

That cant be right?? What am i doing wrong?
 
OK - it depends a little on what you are talking about when you say efficiency. Different people mean different things. Some people mean how much beer they end up with in bottles vs how much grain they used, some people mean how much wort into the fermentor (and how strong) and some people mean how much sugar they managed to extract from the grain compared to a theoretical maximum.

Most people - mean the last one. That includes recipes from the brewing magazines and from the brewing recipe books etc etc. They are comparing the amount of sugar that they managed to get into their kettle, versus how much it is theoretically possible to get.

The other thing is the words "batch size" what do you mean?? do you mean size into fermentor, how much you want to end up with etc etc. Once again, if you are interested in talking the same language as most of the publications and using the terminology they way the brewing software generally does... then batch size means your post boil volume including all the break material and trub.

So - once you have sorted all that out - I think your main problem is how you are defining OG. I'm not sure what the formula you got for OG actually is --- but OG is , well, your OG. You dont work it out, you measure it. And you measured yours at 1.053 in the fermetor.
so lets plug that in - also we will add 2 litres to your batch size to account for the 2L you left in the kettle.

OG = 1.053 (you only use the 53 part) and Batch size = 22L

Now you equation goes like this

efficiency = 53 x 22 x 100 / 307 / 5.5 = 69% which sounds a bit more like a realistic figure

I dont actually know for sure what the various numbers in the formula you were given are for, but it looks to me like a rough guide for calculating efficiency based on a points per pound per gallon system, with built in conversion to metric. But - thats a guess on my part so I'm not sure. and therefore my pulling it to bits and replacing stuff might be completely out of line.

Mind you - if I shove a 22L batch size with 5kg of pale and 0.5kg of munich into pro-mash - I get a gravity of 1.053 with the efficiency set to 69%.... so I reckon I might be on the money.

Do yourself a favour and get a nice brewing spreadsheet (lots of them about) or an evaluation copy of one of the brewing software packages, and after you evaluate it, the full package. They are cheap and will do all this stuff for you and you can stop worrying.

So I'd say your efficiency was 69% - which is just about right for a first time BiaB and very nice indeed. For your next one just assume a nice 70% efficiency. A little higher for a "low gravity" brew and a little lower for a "higher gravity" brew and you will be pretty close.

Congratulations on the brew and welcome to AG

Thirsty
 
Yeah, thirsty, it looks like what you said, a ppg formula with inbuilt metric conversion.
53 x 22 x 100 / 307 / 5.5 = 69%
the 53,22, and 5.5 are self evident. The 307 would be an average guestimated HWE value. Looks like a rearangement of palmers ppg formula
OG / (maxPPG x Wt / vol) , where Wt is in lb and vol is US gallons. Converting the figures thirsty gave to lb, gal, and using 37ppg, it comes to the same end effect, ie 67%

a good read is palmers how to brew, relevant chapter is here

I also have a spreadsheet which uses the ppg instead of hwe, but all weights and volumes are metric. It allows up to 5 grains, and gives total efficiency, but will also calculate first and second runnings seperately if you want. (not that that effects biab).......I just have to find it. Will post it when I can locate it. ;)
 
Wow... Without actually reading through that properly, just skimming over the numbers, im pretty confused :huh:
 
Wow... Without actually reading through that properly, just skimming over the numbers, im pretty confused :huh:

:lol:
Palmers examples tend to put it into easier perspective ;)
 
Where did that 'edit' button go :unsure:

Heres the sheet, I've added JW and Weyermann data out of beersmith (but I'm too lazy to link the grain types in the calculations to the data itself ;) )

View attachment 21063

If there are any glaring deficiencies in my calculations, please let me know.

It is easier, generally, to just use beersmith, promash, or whatever. The main reason I did this sheet up was to work the individual efficiencies of the runnings for partigyle brewing, or for pinpointing efficiency problems to the mash or sparge. For biab, obviously you would just use the overall total, which is indipendent from the runnings data anyway.
 
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