Help with low efficiency with BIAB

[CaptainCookie]

I have previously posted a description of the simulation here.

Beer club tonight. I'll try to respond to your other questions/requests on Saturday.

Brew on

I'll be looking forward it, Cheers!

 

[doug293cz]

Sweet thanks, could you please share the simulation's math? I'm pretty fond of the beer's maths, also how can I make up for a triple batch?

I'm currently working with 2 batches, a 17lts batch for my normal beer, a red ale, and 7lts for my experiments with new varieties, sorry for using metric system, but I'm more used to it

For the 17lts batch, my target pre-boil is 20lts, the capacity of my kettle, accounting:
-1lt kettle loss
-1lt boil-off
-1lt fermenter loss
but now, I should account 0.8lts sparge loss plus 0.5lts drainage loss (in the case of discarding the dead space after sparge and no performing a bag drainage), I'm right? gonna try to convince my pal to make use of this wasted wort

anyway just accounting with the 20lts pre-boil (5Kg grain bill), for the batch sparge will be:

Tgt vol: 20/2= 10lts
Sparge vol: 10lts
Strike vol: 10+5+0.8= 15.8lts
this calculation will be with only one sparge (10lts), but if I wanna do a double batch, I just pour another 10lts? the same for a third batch? the same goes for a 7lts batch (10lts pre-boil)?

When doing double or triple batch sparges, the strike water to grain ratio can get rather small, which would lead to overly thick mashes, which can lead to difficulty when mashing in, and conversion efficiency drops. The same can happen with single batch sparges involving large grain bills. So, to avoid overly thick mashes the math gets a little more complicated, but still pretty simple. First calculate two target strike volumes as follows:

Strike Vol 1 = Target Pre-Boil Vol / (1 + #Sparge Steps) + Absorption Rate * Grain Wt + MLT Undrainable Vol
Strike Vol 2 = Minimum Acceptable Water to Grain Ratio * Grain Wt​

Then your actual strike volume should be:

Actual Strike Vol = Max(Strike Vol 1, Strike Vol 2)​

You then calculate the sparge volumes (all the same) as:

1st Run Off Vol = Actual Strike Vol - (Absorption Rate * Grain Wt + MLT Undrainable Vol)
Sparge Vol = (Target Pre-Boil Vol - 1st Run Off Vol) / (#Sparge Steps)​

Then make sure the run off volume after each sparge is the same as the sparge volume (i.e. you shouldn't see any additional grain absorption during the sparge steps.)

When doing multiple batch sparges for lower OG beers, you can be at risk for over sparging (sparge runnings SG about 1.010 or lower), which can cause tannin and silicate extraction. To minimize the potential for tannin/silicate extraction you should acidify your sparge water to a pH of 5.8 or lower. You can also use the simulation method linked in my previous post to estimate the SG of your last sparge run off, and if it is less than 1.010, then use fewer sparge steps.

Please, I hate being a pain in the ass, but please I would love to have the detailed calculation using points, I think that just using online calculator is just no fun

Don't worry about asking lots of questions. I am happy to provide whatever knowledge I can to people genuinely interested in learning.

To calculate efficiencies by points, start by calculating the total potential points of your grain bill:

Potential for Grain X = Lbs of Grain X * Points/lb of Grain X
Total Potential Points = Sum of Individual Grain Potentials​

If you want to correct for the moisture content of the grain then multiply the total potential points by (1 - %Moisture / 100%). Most brewing software does not correct for moisture, so if you want your calcs to match, then don't correct for moisture.

Mash efficiency is calculated as:

Total Collected Wort Points = Pre-Boil Wort Points/gal * Gallons of Wort in BK Pre-Boil
Mash Efficiency = 100% * Total Collected Wort Points / Total Potential Points​

If you conduct a sparge, then you need to mix all the wort extremely well before taking the SG sample, since the wort will have significant levels of SG stratification after combining the different run offs. You can also calculate mash efficiency after the boil as follows:

Total Collected Points from Mash = Post-Boil Wort Points/gal * Gallons of Post-Boil Wort in BK - Sugar Points Added During Boil
Mash Efficiency = 100% * Total Collected Points from Mash / Total Potential Points​

If you didn't add sugar during the boil, then the pre-boil and post-boil mash efficiencies should be the same. If you added sugar, the post-boil formula ignores the volume of the sugar added during the boil, so the post-boil calculation will be slightly lower than the pre-boil calculation. The amount of error will depend on just how much sugar was added during the boil.

Your brewhouse efficiency can be calculated as:

Brewhouse Efficiency = 100% * Post-Boil Wort Points/gal * Gallons of Wort in Fermenter / (Total Potential Points + Points Added During Boil)​

Note that if sugar was added during the boil, then your brewhouse efficiency can actually be higher than your mash efficiency. If no sugar was added during the boil, then the brewhouse efficiency has to less than or equal to the mash efficiency.

Brew on

 

[CaptainCookie]

Thanks a lot, this is really what I was looking for, just one last question

Mash efficiency is calculated as:
Total Collected Wort Points = Pre-Boil Wort Points/gal * Gallons of Wort in BK Pre-Boil
Mash Efficiency = 100% * Total Collected Wort Points / Total Potential Points
If you conduct a sparge, then you need to mix all the wort extremely well before taking the SG sample, since the wort will have significant levels of SG stratification after combining the different run offs. You can also calculate mash efficiency after the boil as follows:
Total Collected Points from Mash = Post-Boil Wort Points/gal * Gallons of Post-Boil Wort in BK - Sugar Points Added During Boil
Mash Efficiency = 100% * Total Collected Points from Mash / Total Potential Points

I get it all now, but what do you refer with "Pre-Boil Wort Points/gal" and "Post-Boil Wort Points/gal" and how do you calculate them? that's the only thing I don't get it, sorry for the dumb question. thanks

 

[doug293cz]

Thanks a lot, this is really what I was looking for, just one last question



I get it all now, but what do you refer with "Pre-Boil Wort Points/gal" and "Post-Boil Wort Points/gal" and how do you calculate them? that's the only thing I don't get it, sorry for the dumb question. thanks

Points/gal = (SG - 1) * 1000, so an SG of 1.045 is just 45. Works just like points/lb when grain potentials are given in SG form.

Brew on

 

[TheBrewBrotha]

I love BIAB! FWIW, I have a Grainfather and a three kettle rig but always steer to doing BIAB. I squeeze the life out of my brew bag to drain the excess wort and when done I move the bag of grains to a smaller pot or cooler and whatever else drains is added to the kettle before or during boil. Never had a haze issue with my brews nor "tannins extraction". I cold crash which clears up any haze unless I'm doing a NEIPA. My efficiency ranges from 70-80% and I believe the lower end was due to not using a calc to understand how much strike water was needed. I always assumed starting with 8gal of water for a 5 gal batch was "okay" lol

 

[CaptainCookie]

I love BIAB! FWIW, I have a Grainfather and a three kettle rig but always steer to doing BIAB.

So far I can see that BIAB it's pretty more easy to handle, I always had a question, it's valid to stir the grain during mashing? do it increase the conversion rate? what about recirculation? do you do it? so far I've seen that it's pointless in BIAB

Hey doug293cz, I had checked the link that you give me:

The conversion efficiency in your mash can be measured in real time using the method described here. Anything better than 90% is OK, better than 95% is good, and above 98% is great.

and about the formula of FWmax:

FWmax= 100% * Mgrain * Egrain/(Vmash_water + Mgrain * Egrain)​

I'm guessing that Egrain it's the Extract fine grind, dry basis, right? and what It's value when I'm working with differents grains? in an Imperial stout gonna have like 3 differents Egrains values, thanks

 

[pricelessbrewing]

and about the formula of FWmax:

FWmax= 100% * Mgrain * Egrain/(Vmash_water + Mgrain * Egrain)​

I'm guessing that Egrain it's the Extract fine grind, dry basis, right? and what It's value when I'm working with differents grains? in an Imperial stout gonna have like 3 differents Egrains values, thanks

It would be the weighted average.

10 lbs at 85% + 2 lbs at 70% = ( 10*.85 + 2 * .7 ) / 12 = 82.5%

 

[doug293cz]

So far I can see that BIAB it's pretty more easy to handle, I always had a question, it's valid to stir the grain during mashing? do it increase the conversion rate? what about recirculation? do you do it? so far I've seen that it's pointless in BIAB

Stirring (or recirculation) can help break up the gelatinized layer on the surface of the grits, allowing water better access to the less/non-gelatinized starch under the gelatinized layer. This will speed up the overall gelatinization process, and thus the conversion rate. Stirring should be more effective than recirculation since it can provide higher shear velocities at the surface of the grits.

That said, the smaller the grits (the finer the crush) the less effect stirring/ recirculation will have on the conversion rates.

Recirculation in BIAB is unnecessary in cases where the bag occupies the full volume of the kettle. In cases where the bag is in a basket (or there is just a mesh basket) the volume of wort under and around the basket does not really interact with the grain, and diffusion of sugar out of the constrained grain mass into the "free" volume is fairly low, and stirring doesn't do much to mitigate this effect. To maximize lauter efficiency, you want all your wort to be homogeneous w.r.t. sugar concentration, but with a basket the wort outside the basket will be lower in sugar concentration, and the wort that is absorbed by the grain during lautering will have higher concentration. Recirculation of the wort during the mash will homogenize the wort concentration, so is desirable when using a basket.

Hey doug293cz, I had checked the link that you give me:


and about the formula of FWmax:

FWmax= 100% * Mgrain * Egrain/(Vmash_water + Mgrain * Egrain)​

I'm guessing that Egrain it's the Extract fine grind, dry basis, right? and what It's value when I'm working with differents grains? in an Imperial stout gonna have like 3 differents Egrains values, thanks

In the case of multiple grain potentials, Egrain is just the weighted average of the individual Egrain values. It turns out that:

Mgrain * Egrain = Mgrain_1 * Egrain_1 + Mgrain_2 * Egrain_2 + ... + Mgrain_n * Egrain_n​

Braukaiser's formula only works in metric units, when 1 L of water = 1 kg of water. If using imperial units then the equation becomes:

FWmax= 100% * Mgrain * Egrain/(Vmash_water * Density_water + Mgrain * Egrain)​

Where volume is in gallons and density of water is 8.33 lb/gal (@ 68°F / 20°C.)

Brew on

 

[TheBrewBrotha]

So far I can see that BIAB it's pretty more easy to handle, I always had a question, it's valid to stir the grain during mashing? do it increase the conversion rate? what about recirculation? do you do it? so far I've seen that it's pointless in BIAB

I only recirculate when using the Grainfather as it's recommended for many reasons. Also I personally stir 1-2x when mashing in a GF. When I do BIAB I don't recirculate much, maybe a quick vorlof and I never stir the mash.

 

[CaptainCookie]

I've been checking the lautering efficiency and got a couple questions, about it:

For a double batch sparge (2 sparge steps) the efficiency would be:

Eff_1st_runoff= 100% * V_1st_runoff / (V_1st_runoff + Vgrain_absorption + Vdead_space)
Eff_2nd_runoff= (100% - Eff_1st_runoff) * V_2nd_runoff / (V_1st_runoff + Vgrain_absorption + Vdead_space)
Eff_3th_runoff= (100% - Eff_1st_runoff - Eff_2nd_runoff) * V_3th_runoff / (V_1st_runoff + Vgrain_absorption + Vdead_space)
​

and the overall lauter effiency would be:

Lautering efficiency = Eff_1st_runoff + Eff_2nd_runoff + Eff_3th_runoff
​

do I'm right?? also squeezing the bag won't affect the Vgrain_absorption??

and about this formula

mextract_left_in_lauter = (Vwater_added + Vgrain_absorbed) * sg * extract
​

the extract is no more than "mgrain * egrain", right, just gonna be sure to get it all right

 

[doug293cz]

I've been checking the lautering efficiency and got a couple questions, about it:

For a double batch sparge (2 sparge steps) the efficiency would be:

Eff_1st_runoff= 100% * V_1st_runoff / (V_1st_runoff + Vgrain_absorption + Vdead_space)
Eff_2nd_runoff= (100% - Eff_1st_runoff) * V_2nd_runoff / (V_1st_runoff + Vgrain_absorption + Vdead_space)
Eff_3th_runoff= (100% - Eff_1st_runoff - Eff_2nd_runoff) * V_3th_runoff / (V_1st_runoff + Vgrain_absorption + Vdead_space)
​

and the overall lauter effiency would be:

Lautering efficiency = Eff_1st_runoff + Eff_2nd_runoff + Eff_3th_runoff
​

do I'm right?? also squeezing the bag won't affect the Vgrain_absorption??

and about this formula

mextract_left_in_lauter = (Vwater_added + Vgrain_absorbed) * sg * extract
​

the extract is no more than "mgrain * egrain", right, just gonna be sure to get it all right

I really admire Kai Troester's writings, and I have probably learned more from him about brewing than any other single author. But that said, I find some of his formulas and derivations somewhat obtuse and difficult to follow, and the lauter efficiency exposition I find very confusing myself. I mean no disrespect to Kai, and others may find his formulas more intuitive than I do. So, let's forget what Kai says about lauter efficiency, and start from scratch. This may or may not be better than Kai's approach, but I find it easier to follow.

Also, sorry for the delayed response, but I knew this post was going to require significant effort and time, so I put it off until it was more convenient for me.

All of the equations/formulas given below are valid in both imperial and metric units, which is not the case for those give by Troester. Any volumes involved should all be thermal expansion adjusted to a constant temperature, and for reasons I won't go into, 68°F (20°C) is recommended. The density of water at 68°F (20°C) is 8.33 lb/gal or 0.9982 kg/L.

Let's start by reviewing the general definition of efficiency, that applies to pretty much anything:

Efficiency = Amount_Actually_Obtained / Maximum_Amount_Available

[Eq. 1]​

The equation above is for fractional efficiency, and to convert to percent efficiency you multiply fractional efficiency by 100%. When multiplying efficiencies it is necessary to work with fractional efficiencies, so percentage efficiencies need to be divided by 100% before multiplying.

When it comes to brewing efficiency, the "Amounts" we are interested in are Weights of Extract. Extract is mostly sugar (including dextrines), but also contains proteins, and many other minor components. In some cases we can use volumes in the efficiency formulas if the concentration of the liquid is the same for the numerator and denominator. Gravity points, which are just a proxy for weight, can also be used in many cases.

So let's look at some definitions for some of the efficiencies of interest in brewing. Unfortunately, the terms used by different authors and in different segments of brewing are not always the same, which can lead to confusion. But, if you truly understand the definitions and concepts, you can usually determine what a particular author is referring to. In the following definitions and formulas, Extract always refers to Extract_Weight. Modifiers will be used to describe which particular Extract_Weight is being referenced.

Conversion Efficiency is defined as:

Conversion_Efficiency = Extract_Created_in_Mash / Total_Potential_Extract

[Eq. 2]​

Total_Potential_Extract is the sum of the extract potentials for each of the items in the grain bill, i.e.:

Total_Potential_Extract = Sum(Weight_1 * Yield_Potential_1 + Weight_2 * Yield_Potential_2 + ... + Weight_n * Yield_Potential_n)

[Eq 3]​

Where Yield_Potential is the dry basis, fine grind fractional yield potential for each grain, usually about 0.8 or 80% for base grains. Since most grains have about 4% moisture, the as-is weights should be multiplied by 0.96 (or whatever the appropriate value is for actual moisture content) to obtain the most accurate extract potentials (although many calculators neglect to do this.)

Lauter Efficiency is defined as:

Lauter_Efficiency = Extract_in_BK / Extract_Created_in_Mash

[Eq. 4]​

Or fraction of the extract created in the mash that makes it into the boil kettle.

Mash Efficiency is defined as:

Mash_Efficiency = Extract_in_BK / Total_Potential_Extract

[Eq. 5]​

Mash_Efficiency = Conversion_Efficiency * Lauter_Efficiency

[Eq. 6]​

Brewhouse Efficiency is defined as:

Brewhouse_Efficiency = Extract_in_Fermenter / Total_Potential_Extract

[Eq. 7]​

In order to actually calculate any of the efficiencies above, we need to be able to measure the weight of the extract at various points in the process. But, measuring extract weight in a solution is difficult, so what can we do instead? Two items that are relatively easy to measure are volume and specific gravity (SG), and it turns out we can use these two values to calculate extract weight, as well as water weight in any volume of wort.

Wort_Weight = Wort_Volume * Wort_Density,

[Eq. 8]​

Wort_Density = Water_Density * SG, so

[Eq. 9]​

Wort_Weight = Wort_Volume * Water_Density * SG, and

[Eq. 10]​

Wort_Volume = Wort_Weight / (Water_Density * SG)

[Eq. 11]​

Once we know the wort weight, we can determine the extract weight if we know the weight percent of extract in the wort. It turns out that weight percent (Wt%) of extract is just the °Plato (°P):

°P = 100° * Extract / (Extract + Water_Weight)

[Eq. 12]​

°P = 100° * Extract / Wort_Weight

[Eq. 13]​

And there is an equation that we can use to convert SG to °P, which is:

°P = 1111.14 * SG - 630.272 * SG^2 + 135.9975 * SG^3 - 616.868

[Eq. 14]​

To calculate the Extract in a volume of wort, we need to know the SG and wort volume. From there we calculate the °P of the wort (using Eq 14), and the wort_weight (using Eq. 10). Now calculate Extract and water weight, using:

°P = 100° * Extract / Wort_Weight, so
Extract = Wort_Weight * °P / 100°, and

[Eq. 15]​

Water_Weight = Wort_Weight - Extract

[Eq. 16]​

Calculating Conversion Efficiency

The first efficiency we are interested in is the Conversion Efficiency, so we need to determine Extract Created in Mash and Total Potential Extract. We calculate Total Potential Extract from Eq. 3. To get Extract Created in Mash we will need to solve Eq. 12 for Extract:

°P = 100° * Extract / (Extract + Water_Weight)
Extract = (°P/100°) * (Extract + Water_Weight)
Extract = (°P/100°) * Extract + (°P/100°) * Water_Weight
Extract - (°P/100°) * Extract = (°P/100°) * Water_Weight
(1 - °P/100°) * Extract = (°P/100°) * Water_Weight
Extract = (°P/100°) * Water_Weight / (1 - °P/100°)

[Eq. 17]​

We measure the SG of the wort at the end of mash (after aggressive stirring or recirculation to insure that the SG is uniform throughout) and use Eq. 14 to determine the °Plato of the wort in the mash.

°P_of_Mash_Wort = 1111.14 * SG - 630.272 * SG^2 + 135.9975 * SG^3 - 616.868​

Eq. 8 to Eq. 11 are equally valid for water if we change "Wort" to "Water" and SG = 1, So, we use Eq. 8 and the strike water volume to calculate the Water Weight in mash

Water_Weight_in_Mash = Strike_Volume * Water_Density​

And then use Eq. 17 to calculate the Extract Created in Mash:

Extract_Created_in_Mash = (°P_of_Mash_Wort/100°) * Water_Weight_in_Mash / (1 - °P_of_Mash_Wort/100°)​

Once we have both the Total Potential Extract and Extract Created in Mash, we calculate the Conversion Efficiency using Eq. 2:

Conversion_Efficiency = Extract_Created_in_Mash / Total_Potential_Extract​

Calculating Lauter Efficiency

Calculating lauter efficiency is where my thinking parts ways with Troester's. Troester goes thru calculating a "lauter step efficiency" for each run-off (initial plus sparge(s).) I believe the step efficiency concept to be useless in practice, and not worth calculating. My reasons are that what you really want to be able to do is compare results across no-sparge, single batch sparge, multiple batch sparge, and fly sparge processes. But, a no-sparge lauter efficiency will always be better than the initial run-off step lauter efficiency from a batch sparge, but the eventual lauter efficiency of a batch sparge will always be better than a no-sparge (assuming equal pre-boil volumes.) So, comparing step efficiencies provides no useful information, nor does it help with recipe calculations. To get useful information, you have to compare efficiencies at the end of the full lauter process. Plus it's simpler to just calculate the efficiency for the full lauter process than calculating individual steps.

For lauter efficiency we need to know Extract in BK and Extract Created in Mash. We calculated Extract Created in Mash above when determining conversion efficiency. To calculate Extract in BK we will make use of Eq. 10, 14 & 15. First we calculate Wort Weight in BK with Eq. 10:

Wort_Weight_in_BK = Wort_Volume_in_BK * Water_Density * SG_in_BK​

Next determine the wort's °P with Eq. 14:

Wort_°P_in_BK = 1111.14 * SG - 630.272 * SG^2 + 135.9975 * SG^3 - 616.868​

Next calculate the Extract_in_BK using Eq. 15:

Extract_in_BK= Wort_Weight_in_BK * Wort_°P_in_BK / 100°​

And finally we calculate Lauter Efficiency using Eq. 4:

Lauter_Efficiency = Extract_in_BK / Extract_Created_in_Mash​

Calculating Mash Efficiency

Mash Efficiency can be calculated using either Eq. 5 or Eq. 6, since we calculated the required factors while calculating Conversion Efficiency and Lauter Efficiency. An approximate way to calculate mash efficiency is to divide gravity points in BK by total potential points. In this case gravity points in BK is a proxy for Extract in BK, and total potential points is a proxy for Total_Potential_Points, where there are approximately 46 gravity points per pound of extract.

Calculating Brewhouse Efficiency

To calculate Brewhouse Efficiency, we start by calculating Extract in Fermenter the same way we did for Extract in BK in the Lauter Efficiency section. We then calculate Brewhouse Efficiency using Eq. 7:

Brewhouse_Efficiency = Extract_in_Fermenter / Total_Potential_Extract​

You can also calculate brewhouse efficiency approximately by dividing gravity points in fermenter by total potential points.

Squeezing

Squeezing does affect the grain absorption, since if you get more wort out of the mash, there is less wort left behind. If you get more wort out you also get more extract out, so lauter efficiency, mash efficiency, and brewhouse efficiency are all increased.

Brew on

 

[pricelessbrewing]

The method psoted above by Doug, what I call the “extract weight” method is the *correct* way to calculate these. However, there’s another way that is very close ~0.2% difference that is IMO much simpler.

I call this method total gravity points. Really the only complicated part is the correction formula for measuring conversion efficiency, where the wort volume must be calculated. You cannot use water volume for conversion, despite many software doing so. Most notably being brewers friend, which results in a conversion efficiency ~8% lower than it should be.

All volumes are in reference to room temperature volume, and all gravity readings should be taken at room temperature, ie do not trust a hydrometer temperature correction tool.

The general outline being

Measuring Efficiencies

Efficiency = Total_Gravity_Points_Actually_Obtained / Maximum_Amount_Available

Where Total_Gravity_Points = Wort_Volume * Specific_Gravity
And

Total_Potential_Points = GrainWeight * GrainPPG
Total_Potential_Points = 12 lb * 36 PPG = 432 points

Before we do conversion efficiency, I must first outline the formula for calculating the wort volume from the mash conditions, which is actually quite easy.

GetWortVolumeFromSG(WaterVolume,GrainWeight,GrainPPG,SG)
{
WortWeight = WaterVolume * 8.3304 + GrainWeight * GrainPPG / 46;
WortVolume = WortWeight/(SG*8.3304);
}

Example
GetWortVolumeFromSG(5.25 gallons , 12 lb, 36 ppg , 1.069)
{
WortWeight = 5.25 * 8.3304 + 12 * 36 / 46 = 53.126 lb;
WortVolume = WortWeight / (1.069 * 8.3304) = 5.963 Gallons;
}

Note that the wort volume in the mash is ~0.693 gallons higher than the strike water used, this is due to the volume displaced when the sugar, proteins, and starches dissolve into the water.

Conversion Efficiency is defined as the fraction of the extract converted during the mash to the total potential extract of the grains.

Total_Mash_Points = WortVolume * WortGravity = 411.44
Conversion_Efficiency = WortVolume * WortGravity / Total_Potential_Points
Conversion_Efficiency = 5.963 * 69 / 432 = 411.44 / 432 = 95.24%

note the slight loss of accuracy, but the much simpler math.



Lauter Efficiency is defined as the fraction of the extract converted during the mash that makes it into the kettle.

Lauter_Efficiency = Extract_in_BK / Total _Mash_Points
Lauter_Efficiency = PreboilVolume * PreboilGravity / 411.44
Lauter_Efficiency = 6.70 * 54.57 / 411.44 = 0.8886 = 88.86%



Mash Efficiency is defined as as the fraction of the total potential extract that makes it into the Kettle.

Mash_Efficiency = PreboilVolume * PreboilGravity / Total_Potential_Points
Mash_Efficiency = 6.70 * 54.57 / 432 = 84.63%

OR
Mash_Efficiency = Conversion_Efficiency * Lauter_Efficiency
Mash_Efficiency = 88.86 % * 95.24% = 84.63%

Brewhouse Efficiency is defined as the fraction of the total potential extract that makes it into the fermenter.


Lets assume 1 gallon boil off, so that
OG = preboil gravity points / PostboilWortVolume
OG = 365.62 / 5.7 gallons = 64.14

And batch size (volume into fermenter )
Batch Size = 5.7 gallons – 0.5 gallons = 5.2 gallons

and 0.5 gallons kettle loss.

Brewhouse_Efficiency = Extract_in_Fermenter /Total_Potential_Points
Brewhouse_Efficiency = Wort_Volume_In_Fermenter * OG /432
Brewhouse_Efficiency = 5.2 * 64.14 /432 = 77.2%
Alternatively:
Brewhouse_Efficiency = MashEfficiency * Batch_Size / ( BatchSize + Kettle_Loss)
Brewhouse_Efficiency = 84.63 * 5.2 / ( 5.2 + 0.5) = 77.2%

I'll do another post soon for how to predict efficiencies using this method. I like this method for several reasons, it uses measurements everyone should already be taken, doesn't require any unit conversions, and the math is much simpler. The one down side is the marginal loss in accuracy, but it's really quite small, and is much less than the precision we have given our methods of measuring gravity and volume.

 

[pricelessbrewing]

Predicting Efficiencies, and specific gravities.

We will have a couple general functions to make our lives easier, which are only necessary for mash steps. After the initial mash is done, and no more grains are undergoing conversion, it’s just a matter of tracking wort volume, and total gravity points.

Apologies again for the sig-figs, they’re being used for demonstration.

Remember from the previous post that

Efficiency = Total_Gravity_Points_Actually_Obtained / Maximum_Amount_Available

Water Density = 8.3451 lbs per gallon.

PPG of sucrose is 46 gravity points per pound of sugar per gallon of resultant wort, and remember that the sugar increases volume so this is not equivalent to 1 lb of sugar in 1 gallon of water, but ~0.98^1 ish gallons of water.^1 didn’t do the math to check, but it’s around there.

For mash steps where an infusion of water is added, such as the initial strike, or an additional water infusions, we have to account for increases in Wort Volume where the total water added to the mash, and the increased volume created by the sugar is tracked. Use the function GetWortVolumeFromSG to calculate this.

Conversion Efficiency is defined as the fraction of the extract converted during the mash to the total potential extract of the grains.

As such, Mash SG is directly proportional to the conversion efficiency by using the formula below (credit to @Doug293cz and @Braukaiser). There’s no way to predict conversion efficiency, but assuming mash pH and crush does not change, it’s pretty consistent for most brewers. Overly thick mashes tend to suffer due to osmotic pressure, and decreasing surface area of the grain kernel (decreasing gelatinization).

function PredictMashSG(
WaterVolume,GrainWeight,GrainPPG,ExpectedConversionEfficiency
)

 var ExtractWeight = ExpectedConversionEfficiency *GrainWeight * GrainPPG / 46;
 var WaterWeight = WaterVolume * 8.3304;
 var WortWeight = WaterWeight + ExtractWeight;
 var Plato = 100 * ExtractWeight / WortWeight;
 return +ConvertPlatoToSG(Plato);

;

and

function ConvertPlatoToSG(Plato)

    SG =  +1+(Plato/(258.6-((Plato/258.2)*227.1)));

Example
function PredictMashSG(6 gallons, 12 lb , 36 PPG ,100%)

 var ExtractWeight = ( 100 / 100) *12 * 36 / 46 = 9.3913 lb;
 var WaterWeight = 6 * 8.3451 = 49.98240 lb;
 var WortWeight = WaterWeight + ExtractWeight = 59.37 lb;
 var Plato = 100 * ExtractWeight / WortWeight = 15.8173;
 MashSG =  +ConvertPlatoToSG(15.8173) = 1.06454134…;

Then

Wort Volume * MashSG = MashTotalPoints.
6.69 * 64.54134049 = 431.998977


100 * MashTotalPoints / TotalGrainPoints = Conversion Efficiency

431.998977/ 432 = 99.99976%%

#Note the very slight loss of accuracy here. This loss increases as the amount of SG increases, for a 25 lb batch it’s 99.434… %. This ends in a total OG of ~1.100 – 1.120 for most brewers so that’s sort of a worst case scenario. This very slight loss of accuracy is much less than the instrumental uncertainty.

The rest are fairly straight forward, just a dilution of wort volume and total gravity points.

Continued example
We have an absorption rate of 0.125 gal/lb (Typical for mashtun brewers)

1stRunoffSG = MashSG
1st run off volume = MashWaterAdded – Absorption rate = 4.5 gallons
1stRunoffPoints = Volume * SG = 4.5 * 64.54… = 290.4… Gravity Points
Retained Wort Volume is then 6.69 – 4.5 = 2.19.. gallons
retained wort gravity points = 2.19 * 64.54 = 141.56
//Sanity check!
432 – 290.4 = 141.6 CHECK

Sparge with 1.71 gallons for a total water used of 1.71 gallons. SpargingWortVolume = 2.19 + 1.71 = 3.9 gallons
2ndRunoffSG = retained wort gravity points / SpargingWortVolume
2ndRunoffSG = 141.56 / 3.9 = 36.266…. = 1.0363
2ndRunoffVolume = 1.71 gallons
Note: Since the grains are saturated, there’s no further absorption.
2ndRunoffPoints = Volume * SG = 1.71 * 36.26… = ~62.01… Gravity Points
PreboilGravityPoints = 1st + 2nd RunOffPoints = 62 + 290.4 = 352.4
and again,
SG = GravPoints / WortVolume
= 352.4 / 6.75 gallons = 1.05676 SG


Lauter efficiency = Total Points in preboil / Total points in mash
Lauter efficiency = 100 * 352.4 / 432 = 81.57 %
Mash Efficiency = Total Points in preboil / Total points in grain
Brewhouse efficiency = Total points in fermenter / total points in grain


As you can see, besides the initial mash steps, using this method is relatively easy. All you have to do is track wort volume, and gravity points which is some simple algebra.

 

[CaptainCookie]

Sweet, thank you guys, gonna check it up and post later on any doubts, hope that I can count with you with any further question over others math topics

 

[cod3ck]

...for the sake of keeping it simple -- I just worked with my water chemistry tonight and bumped mash efficiency over 5 points...