calculating efficiency BIAB question

[Beil]

I've just completed my first BIAB (early variation of Dr. Smurtos Golden Ale) and I'm trying to use my figures to work out my conversion efficiency.
I think I'm just confusing myself, so I'll try and write this as clearly as possible.

Aiming for 15L in FV.

Mashed 3.19kg grain in 14.6L water for 75 minutes.

Removed grain bag, squeezed as much wort out and then bucket sparged with 4L poured over the bag (placed on strainer), squeezed as much wort out of bag again.

15.9L (@ 66°c) of wort pre-boil with a gravity of 1.052 (Sample cooled to 20°c)

*now this is where I'm getting confused*

After entering my grain bill into 'wort' homebrew app (made sure associated potential etc was set to the grain I used) the above figures of 15.9L / 1.052 say I got an efficiency of 82.4%.

BUT...

I boiled the wort for an hour and ended up with 12.9L @ 1.056
This was OK as I diluted the wort to 15L / 1.048
This resulting wort was just on target (0.002 lower than I wanted) for volume and gravity for the recipe.
But using these figures (15L/1.048) to calculate efficiency give me 71.8%

This seems more like the efficiency I should get/use as my baseline (and it seems like a good efficiency to me)... I don't see how I could get over 80% efficiency on my first attempt at all grain..

Am I working this out correctly and which reading should I be using to work out efficiency?

I hope that I've kept this simple/ easy to follow/ included correct information/ correct calculations on my behalf..


As for my first BIAB, start to finish including clean up was 6 hours, which I've been told I need to reduce as we ended up having dinner at 9:30 :/

 

[Hpal]

As for my first BIAB, start to finish including clean up was 6 hours, which I've been told I need to reduce as we ended up having dinner at 9:30 :/


You'll have trouble getting it quicker than 5 or 6 hrs, just start earlier.

 

[contrarian]

Sounds to me like there has been a measurement error at some point. Possibly the first gravity sample.

Once sugars are in the wort they can't disappear. There's a simple calculation where you multiply the volume and gravity of the first sample and it will equate to the volume and gravity of another sample. Just use the last 2 gravity numbers.

So in this case 15.9 x 52 = 826.8. For the same wort tone at 1.056 just divide that number by 56 to get the volume. 826.8/56 = 14.76.

The simplest answer is that either gravity or volume measurements are off.

 

[MHB]

Efficiency causes a lot of confusion among home brewers, not among pro brewers, the difference is pro brewers use clearly defined terms so they all know what they are looking at. Sorry if this get a bit long but, you asked...

Essentially efficiency is how much extract you get compared to what the laboratory got when they tested the malt. The lab test will often be converted to potential extract on a dry basis (because the moisture content can change during storage and transport) and it is measured on malt ground to mostly flour.
A really good base malt will have a Fine Grind Dry Basis Potential (FGDB) of around 80%
The moisture content (which doesn't add any extract) will be 2-5% (lets call it 4%)
If we mashed 1kg (1000g) of good base malt as well as the lab did the potential extract would be 1000g X 80% (FGDB) X 1-4% (moisture) = 1000*0.8*0.96 = 768g This would represent 100% "Brew House Efficiency" or what some people call conversion or mash efficiency.
If we got 700g of extract our brewhouse efficiency would be 700/768*100 = 91% (roughly)

You can see that to even start discussing efficiency we need to know the mass of malt and the potential of the malt, it is important to note that not all malts have the same potential. A good rule of thumb is that the darker the malt the lower the potential i.e. Light Crystal will give more extract than Dark Crystal...
In a grain bill with several malts you need to work out each potential, or work out an overall potential for the whole grain bill.
If a grist will 90% Base Malt and 10% Medium Crystal with a potential 76% and a moisture content of 6%. the potential of 1000g would be 900*0.8*0.96 + 100*0.76*0.94 = 691.2+71.44 = 762.64g.
Or (Mass Malt 1*FGDB*(1-Moisture))+(Mass Malt 2*FGDB*(1-Moisture))+(Mass Malt 3*FGDB*(1-Moisture))...

To measure the amount of extract in a wort we use Plato (oP) which is to say the same density as a %WW sugar solution. if we dissolved 100g of sugar in 900g of water we would have a 10% WW sugar solution. We can convert from SG to/from Plato with a simple formula (it isn't exact, but probably closer than the instruments most of us can resolve) SG=(4*oP)/1000 + 1 or the other way (SG-1)*1000/4=oP for example if the SG was 1.050, Plato would be 12.5oP
To work out the amount of extract in 15L of 1.050 wort we need the mass (Volume*Density) ( 15*1.050 = 15.75kg
The mass of extract would be 15.75*12.5/100 = 1.96875kg

If we had mashed 2.75kg of good base malt to get that 1.97kg of extract
The potential would have been 2.112kg our Brewhouse Efficiency would be 1.96875/2.112*100 = 93%

As above boiling the wort reduces the water but not the extract, if you have a higher gravity you still have the same mass of extract. But every time you stick in a spoon, splash a bit, leave a bit in the kettle, run it through a pump, pipe or hose... some extract gets lost so what we call Brewery Efficiency will always be lower than Brewhouse Efficiency, ideally not by all that much tho.

The other efficiency is Overall Efficiency, this is measured into the fermenter, more useful to bigger brewers making the same beer over and over, it includes all the losses but if you know a breweries overall efficiency was 74% and the grain bill isn't changing it makes working out how much malt you need really easy.

Mark

 

[user 44743]

Apologies if I misunderstood the meaning, but I thought the term 'brew house' efficiency was more akin to overall efficiency of the brew-house or process - i.e. including losses to dead space etc - whereas what we call mash efficiency is mainly about sugars collected from the mash and any sparge?

 

[micka80]

I use that wort app, the efficiency figure is for post boil volume, not what gets to the fermenter or pre boil. You probably know that anyway, something seems strange with your Gravity readings.

 

[Bribie G]

I don't do my head in with efficiencies - after several hundred brews and knowing my system intimately, I just go with BrewMate to see what efficiency it calculates for me. Brewers Friend and Beer Smith (both of them fully paid copies at that time) reported virtually the same mash efficiencies so I'm happy that BrewMate is on the right track.

As I posted in another thread, if I dial in 74% as the expected efficiency and BrewMate expects and OG of 1.052 then in most cases I'll hit my OG with regular monotony and I know that the efficiency worked out as expected.

Running your grain bill and volume through my system I'd be looking at 1.050 for an efficency of 74% so that's pretty spot on.

Now, that wouldn't give me 15L into fermenter as there will be some losses.

Edit: micka80 just hopped in with the same concept.

So for a 15L into fermenter brew (and I do a fair few of those for comp brewing as I have a range of FVs and my 20L fermenter gets a frequent work out) I'd adjust my grain bill and post boil volume to take account of those losses.

With BIAB it's important to get on top of losses to trub etc - especially with smaller batches - and you might like to read the thread BIAB Excessive Trub. where there are some handy hints.

Whilst it's fine to understand efficiencies, in the home brew world you are looking, rather, to get as much beer as possible from the grain bill, i.e. increase schooners

 

[Beil]

Hpal: yeah that was my take from it, do it first thing in the morning instead of mid afternoon.

Contrarian: I thought I was being accurate, but evidently not. I shall have to re test my ruler in the pot, I had thought I worked it out at 14mm per litre, so maybe I did miss-read the ruler for my division or I gauged the 14mm wrong.
Hydrometer readings again I could have been off, the temp was definitely 20°c, so unless I need to calibrate my hydrometer incase I buggered it (I tested it last brew and was fine).
Or I'm just reading the hydrometer wrong, reading from the meniscus is a pain in the arse in the test tube, but even then I would only be a Max 0.002 off (which matters) but shouldn't make my results as off as they are?

MHB: I need to sit down with a pen and paper and sack off my phone, trying to do calculations with the phone calculator, switching back and forth between your notes is a blag.
I think I'm following your workings, but getting stuck at the grain potential as I don't have the FGDB, water content etc. My grain bill was made up for me as I wanted to make this brew smoother and the only info I have is in the attached photo, which is potential gravity, or am I missing something and I CAN use those figures with your calculations?
I won't have a printout like this again as I will be buying kgs of grain to follow recipes I find etc, so nailing down efficiency calculations is canny important.
The printout (I've just noticed) for example says an efficiency of 75% with a total volume of 15L/ 1.05, so I must be under the 75%, so my 80+% calculation has to be wrong. But my other 71.8% seems more like a it


According to your calculations, assuming I had the relevant grain info: I can use the wort (in this case 15L @ 1.048) that went into my FV to work out my mash efficiency? (Although thinking, it would be better to use my pre dilution figures incase I can't dilute to the wanted volume, as I will always have to dilute due to my set up)

 

[MHB]

Promash uses the American way of expressing potential Points/Pound/Gallon (PPG).
If you dissolved 1 Pound of Sugar in 1 Gallon your OG would be 1.046 (all in silly US units naturally - Google up a map of the world showing countries still using Imperial)
On your sheet the Weyermann has a potential of 1.040, so if you went 40/46*100 = 87%. That will be FGD and it sounds a bit high to me.
In a brewery every malt delivery comes with a Spec Sheet called a Certificate Of Analysis (COA) that tells us a lot about the malt (Here is an old one) View attachment WM158Mel_Wheat_Malt_Pale.pdf

At a home brewing level we mostly just use a typical yield, with a good malt it wont make much difference. Over the last 10 years the speck on Weyermann pilsner hasn't moved 1/2 of a percent.

Couldn't look at the picture and type at the same time, should have been JW Wheat and the number (1.040) is too high
M

 

[Beil]

Micka80: I wasn't sure of the exact time to take the readings and do the calcs, I keep reading about pre-boil gravity, which made me think that the efficiency was calculated after the mash and you've got all your wort together.
But from other replies, it shouldn't matter if I did it pre or post boil? Not using the volume into fermenter if I diluted it makes sense, I think.

Bribie: because I know I'm always going to have to dilute to make my volume into FV (19L big w pot for kettle and wanting to do bigger than half batches); would you suggest using an efficiency of 70% on my recipe builder and simply aiming to smooth sail my process? At the end I can either top up-to target volume at equal to or lower gravity?
As for trub, I cocked up and didn't wait for the whirlpool to settle properly before emptying kettle into FV through the tap, there was some trub left in the pot and only about 40-50ml liquid if that. I also thought that a mesh sieve would stop any break material that went through the pipe... it didn't, I even have some muslin I used to make hop socks in my beer box that I didn't think to use this time.. while this was happening I just thought meh the break that makes it in can go into the FV (being my first BIAB I can hone my process).
No hop trub as I used previously mentioned hop socks for additions.

MHB: yeah, I'm getting sick of trying to do research and coming across Ameri-*******-can websites and imperial measurements, the practical aspects are fine but I just don't even read anything with measurements.
I figured that because the weights were in kg that even though it said points/pound; that it would just be stupid to have both units of measurements and the potentials should be in metric aswell :/

So the units for potential on the sheet look wrong anyway? Well that's useful when I'm trying to learn haha.. I figured the LHBS would have the specs correct.

 

[contrarian]

Hey Beil, not having a go but measurement errors are common and easy to make and generally when something doesn't seem right it is the simplest possibility rather than the most complex.

The difference between measuring gravity before or after stirring wort could easily be 5 gravity points. Smaller volumes are also trickier as any error, however small is a greater percentage.

Also, don't try to lock in an efficiency for your system as it will vary depending on the grain bill especially when you are targeting higher gravity. For example the difference in efficiency between a 1.040 and 1.080 starting gravity could be anywhere from 5-20% with BIAB.

At a home brew level efficiency is more about getting repeatable results than squeezing every last percentage point out so it is helpful to measure but more in terms of getting used to your system than saving an extras $1-2 on grain.

 

[Beil]

Contrarian: I meant to get back to this thread before now but forgot.
As it happens I put down another brew today, making sure to take accurate measurements, stir everything, strain samples of trubby ****.. and this time my results pre and post boil results (tested with your equation above) lined up (to a fraction of a discrepancy) which is good.
I'm not so much bothered about about the possible savings on grain, at the sizes I'm brewing the cost is **** all. But atleast I can plan accordingly and am coming in above what my recipe calculator is predicting.

This brew came out at 85% efficiency, I'm just chuffed that I'm brewing right.

 

[contrarian]

Glad it worked out for you. It's always a bit tricky learning your system but as you say predictability is more important at this scale.

Just remember that it will change for higher gravity brews so don't expect the same efficiency.

 

[Beil]

Is that because the water becomes too saturated with sugar and it becomes harder to dissolve all the available sugar fully?

As for my system, last brew I used hop socks and didn't filter the wort through muslin/sieve.
This time I didn't use hop socks and thought I'd just filter it all though muslin/sieve contraption. Well, I wasted 1.5L of wort because the muslin got blocked and was taking ages to drain so I sacked it off (for fear of leaving it open for contamination) and figured I'd see what wort was lost to trub to accommodate next brew.

So now I know for next time... hop socks plus sieve wort with muslin to see what hot break gets stopped. I'm pretty sure it was the hops that ****** it up this time, even though there was only 12g pellets in total.

I've been reading that there's not really any point in stopping hot break/hops trub going into FV.

It's only annoying this time because I would have ended up with an extra 2L of beer compared to what I was aiming for, instead of only an extra 0.5L :/

 

[MHB]

Beil
A couple of points.
There are really good reasons for keeping hot break in the kettle where it belongs! This has been discussed often enough, I know there is a part of the home brewing community that is more concerned about quantity than quality - and I keep getting chipped for calling them tight arsed idiots.
A well designed and operated system will leave ~5% of the kettle wort and all the trub in the kettle, think of it as part of the cost of doing business. With a lot of good design and equipment you can get this down to less than 2% - all of the remaining beer will be better for it.

12g of hops in a standard brew doesn't make for 2L of trub, have a look at your boil quality, kettle fining and brewing processes.

We can predict exactly what the gravity of the wort will be in the mash from a simple equation. What makes the sugars move out of the grain into solution is the gradient or difference in concentration. As a consequence the higher the L:G the more sugars get extracted during the mash and the less gets left in the grain to be extracted during sparging.

oP of first runnings = CGAI% / L:G + CGAI%

For example if we chose to mash 4kg of a good base malt with a CGAI (Coarse Grind As Is) (= FGDB*1-%moisture - C/F difference) of 75%; mashing in at various L:G's It takes about 2:1 just to cover the malt with water so starting there. Just in rough numbers about 1L of mash water is left in the grain, so at 2:1 we would be getting `4L of wort at 27.3oP and at 6:1, 20L at 11.1oP, from there we can derive the Kg of extract and the efficiency (before sparging) as we know that 75% of the 4kg (3kg) of extract is available.

2:1 oP = 0.75/2+0.75 = 0.2727, ~27.3oP Volume 4L, kg of extract 1.092 or 37%
3:1 oP = 0.75/3+0.75 = 0.2000, ~20.0oP Volume 8L, kg of extract 1.600 or 53%
4:1 oP = 0.75/4+0.75 = 0.1579, ~15.8oP Volume 12L, kg of extract 1.896 or 63%
5:1 oP = 0.75/5+0.75 = 0.1304, ~13.8oP Volume 16L, kg of extract 2.208 or 73.5%
6:1 oP = 0.75/6+0.75 = 0.1111, ~11.1oP Volume 20L, kg of extract 2.222 or 74%

Pretty easy to see why I'm not really a big fan of high gravity mashing.
Mark

 

[manticle]

Easy to account for loss to trub once you know your system and process.

Even if you believe hot break won't harm the beer (and I'm not in that camp), there is no evidence that a large amount of it is beneficial.

You can recover most of the actual wort in various ways if you feel like you're losing too much.
Leave the sludge where it belongs (bottom of the kettle/compost/my stereo).

 

[Beil]

MHB: I definitely need to look at my system, for starters my spigot requires an angled piece on the inside to reach the bottom of the pot, I was aware of that this brew but didn't get round to buying/installing it. The problem started when I tried to tilt the pot to enable the wort to exit, thus disturbing the pile of trub in the centre from whirlpooling.. yadda yadda blocked my muslin, I gave up for fear of leaving everything exposed.

What do you mean by boil quality?

I used whirlfloc, but tilting the damn kettle negated the effect of that.
Hopefully by weeding out little issues I can fine tune my system of operation, do the best I can with a big w 19L pot, a bucket and a pot we already had...until I can upgrade to a crown urn or something and I don't need to try and squeeze every last drop I can get into the FV

That info is interesting, basically what you can even hope to extract increases exponentially until it almost plateaus, point taken, bigger mash the better

I appreciate your detailed replies to my novice knowledge

Manticle: Yup, I think I'm going to learn something new each time I brew, this only being my second AG and only my 4th brew ever.
Compost get most of my spent grains, the chickens get a couple of trowel fulls, they seem to enjoy what ever is left in the shells.

 

[manticle]

Chickens yum that **** up.

My worms also love it but it will clump, stay hot and get flyblown if you don't mix it up in there.

 

[MHB]

Beil
That was just rough, with a lot of rounding and picking easy numbers, I should have converted the Volume to mass (V*SG), but it was just to demonstrate the relationship.
There are a lot of downsides to trying to get too much out of a piece of equipment, better I think to make 15L or so (max) in a 19L pot, or as you say to get a bigger pot/urn.

Boiling is done for a number of reasons, to bitter the beer, to denature excess/large protein, to sterilise... A good quality boil will optimise all of these processes, if you are getting something like 10% evaporation you will have ticked most of the boxes, hard to do if the kettle is too full and you are limping along worrying about boilovers.
A good rolling boil for an hour or more will help the formation of break material, nice large flock particles that will sink quicker (Stokes Law) and will hold together better, allowing better whirlpooling and wort recovery - and making the beer better at the same time (win-win).

There is lots more that we can do to make better beer, but nothing beats getting the basics right.
Mark