Can I improve my BIAB process? Feedback requested

[TkmLinus]

Greetings!
I have been brewing with BIAB for a couple of years now, I am consistently at 68-70% efficiency and am looking to do a little better. I recently bought a mill hoping that would help increase my numbers, yet they are still roughly the same as I got with pre-crushed grains from Northern Brewer. I am unsure if I can tweak my process and was looking for feedback. Here is my brewday from yesterday, brewing Kama Citra from Northern Brewer (Mash has 9lbs Rahr 2-row and 1 lb Caramel 40). Shot for Mash temp of 152F

1. Start with 7 gallons RO water, pour 5 into kettle(8 gallon kettle).
2. Add 4g Calcium Chloride and 7g Gypsum to kettle with 5 gal. water.
3. Heat water to 158F.
4. Crush grains while heating water (grain mill set to thickness of credit card, about .03), ran grains once.
5. Place bag into kettle, add grains, mix. Water Temp after adding in grains at 153F
6. Wrap kettle in blanket, give grains a mix every 15-20 minutes. Mash for 90 minutes.
7. Temp at end of 90 minute mash is 146F.
8. Remove bag and place in second kettle with the remaining 2 gallons of water, warmed to about 140F.
9. Stir well and let sit for about 10 minutes.
10. Drain grains, squeeze all I can out of the bag, pour the 2 gallons into the big kettle, then brewed recipe as normal.

Ended up with about 4.9 gallons into the fermenter at 12.8 Brix(Gravity 1.052). I ended with 69.77% efficiency according to BrewersFriend.

Any feedback/ advice/ ideas would be greatly appreciated. I am quite happy with what I brew, I am just wanting to get better at it!

Thanks in advance!

 

[grampamark]

You can chase efficiency or you can make beer. Your choice.

You could try tightening up your mill gap. It’s pretty hard to mill too fine for BIAB. Most of the generic, two roller, Cereal Killer-style mills will go down to .025. That would be a place to start.

 

[RM-MN]

Efficiency (mash efficiency, that which controls all other efficiencies) depends on the crush of the grain (highest in the dependencies) and the time. If the crush is fine enough the mash time can be much shorter. From that start, lauter efficiency come into the picture. How good are you at getting the sugars separated from the grain. Brewhouse efficiency is a combination of the upper two plus how much of the wort actually gets to the fermenter. Do you try to leave trub behind? That cuts into your efficiency. Spillage? All of that counts.

 

[CascadesBrewer]

My general advice for improving efficiency is to first measure and understand what is driving your efficiency. With a simple BIAB process, it is usually either with the mash, or with downstream losses. Any place that you leave behind sticky wort, you are driving down your efficiency. On the other hand, with a hoppy beer you might just lose wort to hop absorption, or you might prefer to leave all your trub behind in the kettle.

But...I agree with @RM-MN...for BIAB it is usually grain crush that drives the mash efficiency and that is the main driver with poor efficiency. I would adjust your mill a bit finer and see how it works.

For the record, I feel like I have a very simple process and I have made it easier so I don't have to worry about aggressive squeezing of my grain bag, or steps like a sparge. I tune my recipes around a 73% overall efficiency, and can normally hit my target very close. Your 70% upper end is fine, but I would expect you should be higher than that given you add in a sparge step.

Though "consistently at 68-70%" is not a bad place to be. (Assuming that is your overall efficiency and not your mash efficiency.)

 

[RCope]

It kills me to brew a 5 gallon batch and not get 5 gallons into the keg. I start with 8 gallons, mash for 60-70 minutes, squeeze the hell out of it, and get 80% or better efficiency for a 6.75 gallon batch. After chilling and a second transfer, I get 6 gallons into the fermentor and 5 gallons into the keg. Every. Time.

Thats for 11 to 14 lbs of grain. If more, I add another 1/2 gallon of water, if less, I usually keep it the same and up the boil intensity a bit.

But my grain crush is super fine to the point of lots of flour. So, that's where I'd look if I were you...

 

[doug293cz]

Greetings!
I have been brewing with BIAB for a couple of years now, I am consistently at 68-70% efficiency and am looking to do a little better. I recently bought a mill hoping that would help increase my numbers, yet they are still roughly the same as I got with pre-crushed grains from Northern Brewer. I am unsure if I can tweak my process and was looking for feedback. Here is my brewday from yesterday, brewing Kama Citra from Northern Brewer (Mash has 9lbs Rahr 2-row and 1 lb Caramel 40). Shot for Mash temp of 152F

1. Start with 7 gallons RO water, pour 5 into kettle(8 gallon kettle).
2. Add 4g Calcium Chloride and 7g Gypsum to kettle with 5 gal. water.
3. Heat water to 158F.
4. Crush grains while heating water (grain mill set to thickness of credit card, about .03), ran grains once.
5. Place bag into kettle, add grains, mix. Water Temp after adding in grains at 153F
6. Wrap kettle in blanket, give grains a mix every 15-20 minutes. Mash for 90 minutes.
7. Temp at end of 90 minute mash is 146F.
8. Remove bag and place in second kettle with the remaining 2 gallons of water, warmed to about 140F.
9. Stir well and let sit for about 10 minutes.
10. Drain grains, squeeze all I can out of the bag, pour the 2 gallons into the big kettle, then brewed recipe as normal.

Ended up with about 4.9 gallons into the fermenter at 12.8 Brix(Gravity 1.052). I ended with 69.77% efficiency according to BrewersFriend.

Any feedback/ advice/ ideas would be greatly appreciated. I am quite happy with what I brew, I am just wanting to get better at it!

Thanks in advance!

Are you reporting mash efficiency or brewhouse efficiency? Brewhouse is always lower than mash since brewhouse efficiency = mash efficiency * volume in fermenter / post-boil volume. 68% - 70% mash efficiency can be improved on, especially if you sparge. But might be ok for brewhouse efficiency.

If you are only going to squeeze the bag once during your process, you are better off squeezing it after the initial drain, rather than after the sparge.

Brew on

 

[TkmLinus]

Are you reporting mash efficiency or brewhouse efficiency? Brewhouse is always lower than mash since brewhouse efficiency = mash efficiency * volume in fermenter / post-boil volume. 68% - 70% mash efficiency can be improved on, especially if you sparge. But might be ok for brewhouse efficiency.

If you are only going to squeeze the bag once during your process, you are better off squeezing it after the initial drain, rather than after the sparge.

Brew on

I am going by brewhouse efficiency. I will try squeezing after initial drain and see how that impacts things. I will also start checking mash efficiency, never really thought about it and have just focused on what goes into the fermenter. Thanks!

 

[doug293cz]

I am going by brewhouse efficiency. I will try squeezing after initial drain and see how that impacts things. I will also start checking mash efficiency, never really thought about it and have just focused on what goes into the fermenter. Thanks!

I find brewhouse efficiency to be the least useful of the efficiency metrics. Mash efficiency is the one that determines whether you will hit your OG and volume targets. And the two components of mash efficiency, conversion efficiency and lauter efficiency, are the two metrics you need to diagnose whether a low mash efficiency is due to poor conversion in the mash, or a problematic lauter process.

For determining overall efficiency, efficiency into the bottle or keg - packaged efficiency - is more useful than brewhouse efficiency as it accounts for BK to fermenter as well as fermenter to package losses. Brewhouse only accounts for BK to fermenter losses.

Brew on

 

[NotSure]

I was getting about 68% brewhouse efficiency with BIAB. Then I noticed that the input numbers being used for malt extract didn't account for moisture content, so the extract potential was inflated. Turned-out, I was really at around 75%. So, you may be doing better than you think.

 

[Beermeister32]

If you want to push your efficiency number up without changing your mill gap, run the grist through the mill a second time. Double grinding can be good for around 10% or more efficiency in batches I’ve run.

 

[MikeCo]

I agree with tightening your mill gap as the best way to improve mash efficiency. I have mine set at 0.030 inches and generally get in the mid to high 70s for mash efficiency. Stirring the mash periodically also helps, as you are already doing. You may be able to cut your time down by doing a shorter mash. I rarely do more than 60 minutes.

 

[odie]

I find brewhouse efficiency to be the least useful of the efficiency metrics. Mash efficiency is the one that determines whether you will hit your OG and volume targets. And the two components of mash efficiency, conversion efficiency and lauter efficiency, are the two metrics you need to diagnose whether a low mash efficiency is due to poor conversion in the mash, or a problematic lauter process.

bingo...it all starts here...work on this...

 

[dtashmore547]

not sure if my input can help, I began with a BIAB process in an electric boiler, using 20 liters of water and 6 liters of sparge water and generally managed mid 80's in efficiency, I changed to a basket which I can rest on a frame to sparge and also introduced a clip on pump which can pick up from the center of the boiler to lauter the wort direct into the grain bed with a whirlpool on the wort I can rinse a lot of the sugars out of the grain whilst cleaning up the wort for boiling, I then sparge with 6 to 8 liters of water, this had pushed up my efficiency to over 90 percent. I get around 1.042 from 4 kg of base grain in 27 liters of liquor, I have never milled my grain fine and only set the mill to crush the grain, I find too much flour clogs up and stifles the mash.
I believe the answer is to get the sugars out of the mash by either sparging or lautering, too much squeezing can have is own pitfalls.

 

[TkmLinus]

I find brewhouse efficiency to be the least useful of the efficiency metrics. Mash efficiency is the one that determines whether you will hit your OG and volume targets. And the two components of mash efficiency, conversion efficiency and lauter efficiency, are the two metrics you need to diagnose whether a low mash efficiency is due to poor conversion in the mash, or a problematic lauter process.

For determining overall efficiency, efficiency into the bottle or keg - packaged efficiency - is more useful than brewhouse efficiency as it accounts for BK to fermenter as well as fermenter to package losses. Brewhouse only accounts for BK to fermenter losses.

Brew on

Thanks for the info. I was under the impression that brewhouse was the most useful since it is based upon what goes in the fermenter. Thanks for the information about the different efficiency metrics, makes a lot of sense. The beauty of this hobby is that there is always something new to learn. I'll start looking at conversion efficiency and determine if I need to tweak things there. Thanks again!

 

[doug293cz]

Thanks for the info. I was under the impression that brewhouse was the most useful since it is based upon what goes in the fermenter. Thanks for the information about the different efficiency metrics, makes a lot of sense. The beauty of this hobby is that there is always something new to learn. I'll start looking at conversion efficiency and determine if I need to tweak things there. Thanks again!

You need to be careful with conversion efficiency - a lot of calculators use incorrect formulas, with Brewer's Friend being one of them. The correct method is described here.

Brew on

 

[jdudek]

You can chase efficiency or you can make beer. Your choice.

or you can do both.

 

[grampamark]

or you can do both.

Brewing is part art, part science. Whether one leans more towards the art or the science probably depends on why that person started brewing in the first place.

 

[jdudek]

bingo...it all starts here...work on this...

Agreed again. Start with conversion. You put some grains in some amount of water. There's a maximum gravity you can get out of that process. As other have said, finer crush and time will get you there. I don't crush as fine as others here (0.04) but often mash for 1.5 to 3 hours, depending on what else is going on in my day. I easily hit between 95 and 100% conversion efficiency.

Next there's lauter efficiency. Again that's straightforward: how much of the liquid will you get out of the grain. It's a controllable process. If you just let it drain, probably around 70% efficiency. If you squeeze, maybe 73%, if you sparge, again a bit more. Doug has a nice chart somewhere where he simulated efficiency vs sparge steps with different grain absorption rates. In the end, given a constant boil of rate and a constant fermenter target, you'll always want to hit the same pre-boil volume. I just let it drain and squeeze if needed to hit the target. therefore this step will give you different efficiencies for different recipes. It's good to keep in mind, there's no sense in trying to replicate the same efficiency numbers every time, as it would necessarily yield different volumes (for different grain bills).

And that's your mash efficiency (conversion X lautter). I agree it's pretty much all that matters. The rest will be some mechanical losses in transferring wort, which In brew in a bag should be next to nothing. maybe 0.1gallon of sludge at the bottom of the kettle...

And yes, calculators out there are a bit wonky, as you've noticed yourself (grain moisture, gallon of wort vs gallon of water, etc...). If you want to account for everything, I suggest the Doug's spreadsheet. Also, the priceless biab calculator online is pretty good.

 

[NotSure]

You need to be careful with conversion efficiency - a lot of calculators use incorrect formulas, with Brewer's Friend being one of them. The correct method is described here.

Brew on

I had a go at changing (i.e. correcting) the calculator I have on my site today using the Braukaiser link and Jdudek's experiment data. Looks like there are three main issues with what's out there to calculate efficiency today apart from no one agreeing on the definitions:
(1) Sugar is not 46 ppg, it's 43 ppg. This is an easy fix to the equations already used by most today including myself.
(2) Plato needs to be used, not SG for the base of the equation as is in the Braukaiser link. Had no luck finding the Peter Hopcroft reference. Correcting for sugar ppg worked for lower gravity wort using the common equation, but fell apart as the gravity increased.
(3) Moisture Correction needs to be accounted for with each grist addition.

I think I'll try to pump-out a correct calculator with a generic enough definition of efficiency that won't annoy anyone in the next couple days.

 

[odie]

Brewing is part art, part science. Whether one leans more towards the art or the science probably depends on why that person started brewing in the first place.

perhaps what separates a brewery from a brew pub...commercial beer from craft beer...

commercial brewers have to replicate an exact recipe and results over and over and over. Even smaller regional and local breweries.

Your local brew pub is always changing things up...like grandma's cooking...

Not sure what point I would call it but I'd say if they are selling anything through a second party, even just local stores or bars, then they are being very exacting in their process.

 

[BrewHack]

I only have three mashes under my belt, but the last one I was able to bring my efficiently up from 65% to 75%. I changed several things so I'm not sure what effect each change made individually.

1. I milled the malt almost to flour.

2. Corrected water profile with salts.
3. More mash water, 21L to 5 kg of grain
4. I preheated my insulation (sweater, vest, and sleeping bag) in the dryer. And I rested my kettle on a heating pad.
5. I mashed for 90 mins. Only lost 1degC over that time
6. I used a potato masher to squeeze the wart from the grain.
7. I sparged with a perforated bucket 4L at a time and used the potato masher between bucket fills. Sparge water was heated to 65C. I just added water this way until I was at my preboil level. Measured with a measuring stick.

I haven't tasted the beer yet, so I don't know if I created tannins.

 

[jdudek]

Nice sparge setup! proper home-made-like. I'd say the mill to flower will have the biggest impact... followed by the sparge and squeeze. Former will impact the conversion efficiency and latter the lauter efficiency.

 

[doug293cz]

...

Next there's lauter efficiency. Again that's straightforward: how much of the liquid will you get out of the grain. It's a controllable process. If you just let it drain, probably around 70% efficiency. If you squeeze, maybe 73%, if you sparge, again a bit more. Doug has a nice chart somewhere where he simulated efficiency vs sparge steps with different grain absorption rates. In the end, given a constant boil of rate and a constant fermenter target, you'll always want to hit the same pre-boil volume. ...

The nice chart:

Grain absorption rate is affected by thoroughness of draining and/or squeezing. A well conducted fly sparge can get a few percentage points more lauter efficiency than a triple batch sparge @ 0.12 gal/lb grain absorption rate.

Link to my spreadsheet. You should download a copy and open it in Excel or OpenOffice, so you can use the "Goal Seek" tool. To determine conversion efficiency, use the Goal Seek tool. Put "K48" in the formula input field (this is the cell who's value you want to adjust to match your actual end of mash SG), put your actual end of mash SG in the target value input field, and put "B16" in the variable cell input field. Then run the Goal Seek tool. Goal seek will adjust the value of conversion efficiency (B16) so that the simulated end of mash SG (K48) matches your actual end of mash SG.

If you don't have Excel or OpenOffice, then you can copy my spreadsheet to your own local Google Sheets page. You then have to download the Goal Seek add-on, since it is not built into the base app.

Just for information, @pricelessbrewing used my spreadsheet formulas to build his on-line calculator (but has since refactored the formulas to increase performance. The formulas aren't as rigorous, but the error compared to the rigorous formulas is small.)

Brew on

 

[BrewHack]

The nice chart:

You should download a copy
Brew on

Cool. I'll take a look. Thanks!

 

[doug293cz]

I had a go at changing (i.e. correcting) the calculator I have on my site today using the Braukaiser link and Jdudek's experiment data. Looks like there are three main issues with what's out there to calculate efficiency today apart from no one agreeing on the definitions:
(1) Sugar is not 46 ppg, it's 43 ppg. This is an easy fix to the equations already used by most today including myself.
(2) Plato needs to be used, not SG for the base of the equation as is in the Braukaiser link. Had no luck finding the Peter Hopcroft reference. Correcting for sugar ppg worked for lower gravity wort using the common equation, but fell apart as the gravity increased.
(3) Moisture Correction needs to be accounted for with each grist addition.

I think I'll try to pump-out a correct calculator with a generic enough definition of efficiency that won't annoy anyone in the next couple days.

1) Sucrose (the sugar used by Brix and Plato to establish their scales) does indeed have a potential of 46.173 pts/lb. Calculating its potential at 43 pts/lb stems from a misunderstanding of the definition of potential. The potential of an ingredient is defined as the SG that would be obtained by dissolving all of the potential extract from 1 lb of the ingredient in enough water to create 1 gal of solution/wort. It is not defined by starting with 1 gal of water. Making 1 gal of solution from 1 lb of sucrose requires only 0.926 gal of water.
2) Yes the Braukaiser equations for calculating conversion efficiency require that the SG be measured in, or converted to, °Plato, which is simply the weight % of extract in the wort/solution:

°P = 100°P * Extract_Weight / (Extract_Weight + Water Weight)​

Braukaiser assumes calculations are done in metric units, and makes use of the fact that 1 liter of water weighs about 1 kg to substitute water volume for water weight in the above equation. This is not totally rigorous as the weight of 1 liter of water at 20°C (68°F) is 0.9982 kg. When using imperial units, you need to calculate the weight of the water by multiplying gallons by 8.3304 lb/gal (water's density at 20°C (68°F.)

Here is the derivation of the accurate formula for conversion efficiency that Braukaiser attributes to Peter Hopcroft:

Conversion efficiency is defined as 100% * Extract_Actual / Extract_Max​

​

Since we don't know the actual weight of extract produced in the mash, we must use the measured SG (in °P) and strike water weight to calculate the created extract weight​

​

SG°P = 100°P * Extract_Weight / (Extract_Weight + Water_Weight)​

SG°P * (Extract_Weight + Water_Weight) = 100°P * Extract_Weight​

SG°P * Extract_Weight + SG°P * Water_Weight = 100°P * Extract_Weight​

SG°P * Water_Weight = (100°P - SG°P) * Extract_Weight​

Extract_Weight = SG°P * Water_Weight / (100°P - SG°P)​

​

If we substitute the above formula for Extract_Weight into the definition of conversion efficiency, we get:​

​

Conv_Eff = 100% * [°PActual * Water_Weight / (100°P - °PActual)] / [°PMax * Water_Weight / (100°P - °PMax)]​

Conv_Eff = 100% * [°PActual / (100°P - °PActual)] / [°PMax / (100°P - °PMax)]​

Conv_Eff = 100% * (°PActual / °PMax) * (100°P - °PMax) / (100°P - °PActual)​

3) Correct. If you don't account for the moisture content of the grain, you will underestimate the actual conversion efficiency.

​

An equation for °PMax that doesn't depend on units of measurement is:

°PMax = Grain_Wt * Max_Extract% / (Grain_Wt * Max_Extract% + Strike_Vol * Water_Density)​

​

As is Grain_Wt needs to be corrected to dry Grain_Wt using the formula:​

Dry Grain_Wt = As is Grain_Wt * (1 - %Moisture/100%)​

SG can be converted to °P using the equation:

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

​

°P can be converted to SG using the equation:

SG = 1 + (°P / (258.6 - (°P / 258.2) * 227.1))​

​

Brew on

 

[FunkedOut]

Lots of good advice given.
One aspect not yet mentioned is accuracy.
All the calculations are worthless if your measurements are inaccurate.
Volumes, weights, gravities, temperatures, pH...
Is there really 10lbs in that 10-pound grain bag?
Do you trust the grain data you have?
Are those kettle markings proven?
Are your gravity samples at the right temp?
Thermometer calibrated?
Hydrometer proven?
Question and verify everything.

 

[doug293cz]

Lots of good advice given.
One aspect not yet mentioned is accuracy.
All the calculations are worthless if your measurements are inaccurate.
Volumes, weights, gravities, temperatures, pH...
Is there really 10lbs in that 10-pound grain bag?
Do you trust the grain data you have?
Are those kettle markings proven?
Are your gravity samples at the right temp?
Thermometer calibrated?
Hydrometer proven?
Question and verify everything.

Good point. Most efficiency calcs at the homebrewer level are only good to about +/- 3% - 4%, because of the measurement inaccuracies in the items mentioned above. So, if you get a mash efficiency of 78% on one brew, and 80% on another, statistically there is no difference.

Brew on

 

[TkmLinus]

Good point. Most efficiency calcs at the homebrewer level are only good to about +/- 3% - 4%, because of the measurement inaccuracies in the items mentioned above. So, if you get a mash efficiency of 78% on one brew, and 80% on another, statistically there is no difference.

Brew on

Thanks for all the awesome info! It is a lot to digest and nerd out on!

What is the deal with Mash times and efficiency? I have read an hour is long enough for conversion and that extra time doesn't help conversion. I have also read that longer times help with conversion. There seems to be conflicting advice on this.

 

[jdudek]

depends on your definition of "enough"

basically if conversion is complete, then more time won't make a difference. if you have a fine crush, it may take less than 45 minutes. Coarser crush, it will take longer. For a given crush (and other variables like temp stability, ph, how well the water comes in contact with the grain, etc.) 1h may give you say 90% conversion which many people will call good enough. You could leave it there another hour, and maybe you could get a few extra points of the grain.

in general, more time will help you get closer to 100%. once you're there, more time does not change anything. And I would imagine that if other mash parameters are sub optimal, then more time won't help either (imagine for example a really bad crush where some of the kernels remain whole and sugar is not exposed)

in the end consistency is most important to help you design your recipes. If you always get around 90% conversion efficiency, then that's what you dial into your software and move on. A bit less efficiency at the homebrew scale only means you'll need to spend a few more cents on a bit of extra grain.

 

[RM-MN]

basically if conversion is complete, then more time won't make a difference. if you have a fine crush, it may take less than 45 minutes. Coarser crush, it will take longer.

With a very fine crush it can be all over in less than 30 minutes. However, don't cut that time too short, it seems that it takes that 30 minutes to get the color and flavor out of the grains. A really short mash that still has full conversion may have no flavor. BTDT.

 

[NotSure]

1) Sucrose (the sugar used by Brix and Plato to establish their scales) does indeed have a potential of 46.173 pts/lb. Calculating its potential at 43 pts/lb stems from a misunderstanding of the definition of potential. The potential of an ingredient is defined as the SG that would be obtained by dissolving all of the potential extract from 1 lb of the ingredient in enough water to create 1 gal of solution/wort. It is not defined by starting with 1 gal of water. Making 1 gal of solution from 1 lb of sucrose requires only 0.926 gal of water.
2) Yes the Braukaiser equations for calculating conversion efficiency require that the SG be measured in, or converted to, °Plato, which is simply the weight % of extract in the wort/solution:

°P = 100°P * Extract_Weight / (Extract_Weight + Water Weight)​

Braukaiser assumes calculations are done in metric units, and makes use of the fact that 1 liter of water weighs about 1 kg to substitute water volume for water weight in the above equation. This is not totally rigorous as the weight of 1 liter of water at 20°C (68°F) is 0.9982 kg. When using imperial units, you need to calculate the weight of the water by multiplying gallons by 8.3304 lb/gal (water's density at 20°C (68°F.)

Here is the derivation of the accurate formula for conversion efficiency that Braukaiser attributes to Peter Hopcroft:

Conversion efficiency is defined as 100% * Extract_Actual / Extract_Max​

​

Since we don't know the actual weight of extract produced in the mash, we must use the measured SG (in °P) and strike water weight to calculate the created extract weight​

​

SG°P = 100°P * Extract_Weight / (Extract_Weight + Water_Weight)​

SG°P * (Extract_Weight + Water_Weight) = 100°P * Extract_Weight​

SG°P * Extract_Weight + SG°P * Water_Weight = 100°P * Extract_Weight​

SG°P * Water_Weight = (100°P - SG°P) * Extract_Weight​

Extract_Weight = SG°P * Water_Weight / (100°P - SG°P)​

​

If we substitute the above formula for Extract_Weight into the definition of conversion efficiency, we get:​

​

Conv_Eff = 100% * [°PActual * Water_Weight / (100°P - °PActual)] / [°PMax * Water_Weight / (100°P - °PMax)]​

Conv_Eff = 100% * [°PActual / (100°P - °PActual)] / [°PMax / (100°P - °PMax)]​

Conv_Eff = 100% * (°PActual / °PMax) * (100°P - °PMax) / (100°P - °PActual)​

3) Correct. If you don't account for the moisture content of the grain, you will underestimate the actual conversion efficiency.

​

An equation for °PMax that doesn't depend on units of measurement is:

°PMax = Grain_Wt * Max_Extract% / (Grain_Wt * Max_Extract% + Strike_Vol * Water_Density)​

​

As is Grain_Wt needs to be corrected to dry Grain_Wt using the formula:​

Dry Grain_Wt = As is Grain_Wt * (1 - %Moisture/100%)​

SG can be converted to °P using the equation:

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

​

°P can be converted to SG using the equation:

SG = 1 + (°P / (258.6 - (°P / 258.2) * 227.1))​

​

Brew on

Thanks for this. Here's the Braukaiser conversion efficiency equation:
Conversion Efficiency, Brewing Calculators

I left some of the fields I normally hide visible for the time being. Hopefully I got it right and I'm still testing it. Still getting my head around this.

 

[cmac62]

I think the time factor has more to do with fermentability that conversion. With 100% conversion all the starch is sugar, but what kind of sugar. More time at mash temps allows enzymes to convert more of those sugars to fermentable sugars.

 

[odie]

View attachment 724056

looking at your set up I'll give a few suggestions...opinions are like a**holes...lol

First, I'm guessing you have no spigot. That would mean that your basket should drop all the way to the bottom so there is no/minimal dead space.

So...I would suggest a full volume mash and forget the sparge. And hoist the bag with a winch and let it hang during the entire boil and squeeze it a bit. That will boost your efficiency greatly.

If you want to sparge anyway...then you need to close off the side holes in the basket first. That will ensure your sparge water flows down thru the entire grain bed and nothing escapes out the sides. Water ALWAYS takes the path of least resistance. Take a roll of flashing to close the sides like this.

BTW, I plan to attempt a sparge like yours (but with closed sides) on my next RIS. But that is a grain heavy, high gravity beer with a low mash efficiency. I think a sparge can help greatly in that particular case.

 

[odie]

What is the deal with Mash times and efficiency? I have read an hour is long enough for conversion and that extra time doesn't help conversion. I have also read that longer times help with conversion. There seems to be conflicting advice on this.

It's a factor of your crush and also water ratio. The warm water has to get to ALL the available starches for the enzymes to convert it to sugars. A very fine/tight crush for BIAB exposes maximum starch so the conversion happens very fast.

A traditional crush is more coarse so that you may lauter and sparge without clogging the system. It takes more time for the warm water to penetrate to all the starches and let the enzymes do their thing.

Either way, once there is no starch left there is nothing more. Might happen in 20 min, might happen in 2 hours. That's pretty much 100% conversion efficiency. But once you are there, another hour/day/week will gain you no more sugar. It's really just knowing how much time is needed for your particular situation.

Now how much of that 100% conversion you can actually get out of the wet grain and into the kettle is the trick. And that's a factor of your methods, not time.

 

[BrewHack]

Take a roll of flashing to close the sides like this.

Awesome idea! This is a game changer.

My pot is not big enough for a full volume mash, I'll try the flashing.

 

[beerisyummy]

Greetings!
I have been brewing with BIAB for a couple of years now, I am consistently at 68-70% efficiency and am looking to do a little better. I recently bought a mill hoping that would help increase my numbers, yet they are still roughly the same as I got with pre-crushed grains from Northern Brewer. I am unsure if I can tweak my process and was looking for feedback. Here is my brewday from yesterday, brewing Kama Citra from Northern Brewer (Mash has 9lbs Rahr 2-row and 1 lb Caramel 40). Shot for Mash temp of 152F

1. Start with 7 gallons RO water, pour 5 into kettle(8 gallon kettle).
2. Add 4g Calcium Chloride and 7g Gypsum to kettle with 5 gal. water.
3. Heat water to 158F.
4. Crush grains while heating water (grain mill set to thickness of credit card, about .03), ran grains once.
5. Place bag into kettle, add grains, mix. Water Temp after adding in grains at 153F
6. Wrap kettle in blanket, give grains a mix every 15-20 minutes. Mash for 90 minutes.
7. Temp at end of 90 minute mash is 146F.
8. Remove bag and place in second kettle with the remaining 2 gallons of water, warmed to about 140F.
9. Stir well and let sit for about 10 minutes.
10. Drain grains, squeeze all I can out of the bag, pour the 2 gallons into the big kettle, then brewed recipe as normal.

Ended up with about 4.9 gallons into the fermenter at 12.8 Brix(Gravity 1.052). I ended with 69.77% efficiency according to BrewersFriend.

Any feedback/ advice/ ideas would be greatly appreciated. I am quite happy with what I brew, I am just wanting to get better at it!

Thanks in advance!

This is almost exactly what I do. I'm pretty sure I usually end up with 68-72% mash efficiency, but sometimes I forget to measure stuff lol ... I use the calculators on brewersfriend.com and am also reading and trying to understand (I'm no scientist) the formulas and procedures recommended in Daniels "Designing Great Beers." In discussing crush & yield, Palmer seems to conclude that the difference in yield between a coarser and a finer crush is not all that significant; but as BIABers we don't have to worry about lautering, so it makes sense to crush as fine as possible for that extra je ne sais quoi... and anecdotally many BIABers seem to believe that it does help substantially. I just have to make sure, if I have a lot of flour, that I stir well at dough-in so I don't end up with grist dumplings!
Also anecdotally, I will opine that I believe the dunk-sparge we both use does give us a bit of extra sugar.
Elsewhere on this forum, I read someone's description of the three-bucket squeeze, and I've been doing it. Place one bucket on the floor, and place a second bucket in it that has holes drilled in the bottom. Place the grain bag in that, put the third bucket on top of that, and stand in it. Depending on how much I've let the bag drain already, I'll usually get at least another quart of wort. $5 a bucket, it's a pretty inexpensive and appealingly homely piece of equipment. Sure you got a couple more things to clean up, but it ain't no thang.
Finally, I'll just pass on the wisdom of one friend who said simply, if you're not getting the extraction you want, then just throw in an extra pound of base malt in your next brew!

 

[beerisyummy]

perhaps what separates a brewery from a brew pub...commercial beer from craft beer...

commercial brewers have to replicate an exact recipe and results over and over and over. Even smaller regional and local breweries.

Your local brew pub is always changing things up...like grandma's cooking...

Not sure what point I would call it but I'd say if they are selling anything through a second party, even just local stores or bars, then they are being very exacting in their process.

Preach. As a home brewer, I'm far more interested in trying new things as often as possible, than in brewing the same thing over and over. And if I do repeat brews it's usually because I'm interested in tweaking something the next time. This is why when friends really like something I've made and suggest I go into business, I always say I make a helluva good spaghetti sauce too, but that does not mean I have any business opening an Italian restaurant.

 

[K_tile]

If you want to go down a rabbit hole research brewing with enzymes. Just a pinch will do ya for mash efficiency.

 

[BrewHack]

I haven't tasted the beer yet, so I don't know if I created tannins.

Tasted the beer, and it had astringency. I'm guessing I did release tannins by using the potato masher. Had to dump it.

Won't do that again.

 

[odie]

If you are blaming the potato masher then you are really grasping for straws...IMO