What's Your Typical Conversion Efficiency?

[Epos7]

I've been striving to improve my conversion efficiency. Over 95% seems to be the magic number quoted by Braukaiser and many of the experts on this forum. The biggest variable impacting conversion efficiency is grain crush.

http://www.braukaiser.com/wiki/inde...ng_Efficiency#Measuring_conversion_efficiency

I struggle to hit even 90% with my current mill on its lowest gap setting. I'm curious what type of results other BIAB brewers are typically seeing. Please note I'm referring specifically to conversion efficiency, not mash efficiency or brewhouse efficiency.

Mostly I'm just curious to see if 95% and over is easily achieved by most homebrewers, or if the majority of people settle for less efficient conversion of starches into sugars. Brewer's Friend appears to assume 85% conversion efficiency in their recipe builder, so maybe they are assuming that's what the average homebrewer sees.

 

[petrolSpice]

For BIAB I think you should be less worried about conversion efficiency and more worried about overall mash efficiency, which would be how much of the potentially available sugar in the grains actually makes it into the kettle.

 

[TexasWine]

For BIAB I think you should be less worried about conversion efficiency and more worried about overall mash efficiency, which would be how much of the potentially available sugar in the grains actually makes it into the kettle.

All efficiencies in all methods of brewing have a direct tie back to conversion efficiency. If conversion is low, all other efficiencies will be impacted.

Aiming to have a reasonable conversion efficiency is very worthwhile and it should be one of the variables examined if other efficiencies are lower than anticipated.

One question I would ask the OP, if you're hitting your OG and volume, are you sure you're using the correct volume to calculate your conversion efficiency?

 

[Epos7]

One question I would ask the OP, if you're hitting your OG and volume, are you sure you're using the correct volume to calculate your conversion efficiency?

I'm using my strike water volume and final mash gravity to calculate conversion efficiency. I haven't hit both my OG and volume yet, though I'm inching closer. I did hit my OG on my last batch, but undershot slightly on volume.

 

[RedlegEd]

Hi. Quite honestly, I just look at efficiencies to improve my process. I use Brewer's Friend to calculate my efficiencies (from conversion to brewhouse.) One thing to remember is the accuracy of the Points / Pound / Gallon (ppg) value given to the grain you are using significantly affects your conversion efficiency number. I look at this like the EPA mileage estimate for a vehicle. This is theoretically the amount of sugar "points" available from the grain, but as is often said, "YMMV." If your grain is relatively fresh, you get a really good crush, and it's got lots of starches to convert, you could easily exceed that and get a really good (i.e. >100%) conversion efficiency. I think the major malsters provide a generalized PPG of the malt type rather than a specific number for each sack/lot. So your grain might have a higher or lower than expected PPG, which affects your conversion %. I monitor what I get with the bulk grain I have on hand so I know what to expect and adjust the recipe accordingly. If you can adjust the crush or another factor that provides a few extra points with the same grain, then you know you are on the right track. Just my $0.02. Ed

 

[doug293cz]

I'm using my strike water volume and final mash gravity to calculate conversion efficiency. I haven't hit both my OG and volume yet, though I'm inching closer. I did hit my OG on my last batch, but undershot slightly on volume.

You cannot calculate conversion efficiency from those two variables alone. At a minimum you have to add grain bill weight along with strike volume and mash wort OG. Can you provide more details of your method?

Brew on

 

[Epos7]

You cannot calculate conversion efficiency from those two variables alone. At a minimum you have to add grain bill weight along with strike volume and mash wort OG. Can you provide more details of your method?

Brew on

Oh I know, just specifying which volume I'm including in the calculation. I got a lot of help on my method in the mill gap thread, I think you had a lot of good info, so thanks again.

I'm just trying to get an idea of how common 90%+ conversion efficiency is.

 

[pricelessbrewing]

Usually I'm in the range of 93-96% for a typical 1.060, brew depending on the grains used, the mash volume, mash temp, and the crush.

I think a lot of people are confusing mash efficiency with conversion efficiency and voting without reading the braukaiser link for definitions. Brewersfriend uses different terminology, describing mash efficiency as conversion efficiency. And calling kettle efficiency as mash efficiency.

For more info you can read my article st http://pricelessbrewing.github.io/methods/Efficiency

 

[chickypad]

I think a lot of people are confusing mash efficiency with conversion efficiency and voting without reading the braukaiser link for definitions. Brewersfriend uses different terminology, describing mash efficiency as conversion efficiency. And calling kettle efficiency as mash efficiency.

Looks like it to me too, otherwise all those people would be complaining about really low brewhouse efficiencies. I voted over 95%, using kai's formulas with assumptions I'm typically 94-96%.

 

[doug293cz]

Usually I'm in the range of 93-96% for a typical 1.060, brew depending on the grains used, the mash volume, mash temp, and the crush.

I think a lot of people are confusing mash efficiency with conversion efficiency and voting without reading the braukaiser link for definitions. Brewersfriend uses different terminology, describing mash efficiency as conversion efficiency. And calling kettle efficiency as mash efficiency.

For more info you can read my article st http://pricelessbrewing.github.io/methods/Efficiency

Actually, BrewersFriend uses the "correct" definition of "Conversion Efficiency"

"Conversion efficiency has been introduced to asses the performance of mash conversion before lauter losses take effect. Since it is difficult to measure the volume of wort in the mash, this efficiency is best assessed by calculating the highest possible mash wort gravity based on grist extract potential and mash water amount and then comparing the actual mash gravity to it. The mash gravity test for conversion efficiency allows brewers to troubleshoot low efficiency by determining if significant efficiency is lost during the mashing step."

http://www.brewersfriend.com/2012/11/30/making-sense-of-efficiency-definitions/​

And,

"1) Conversion Efficiency: The percentage of total available sugars that were extracted from the grains inside the mash tun."

http://www.brewersfriend.com/faq/#brewsessions5​

They tend to use "Mash Efficiency", "Pre-Boil Efficiency", and "Kettle Efficiency" interchangeably.

Looks like it to me too, otherwise all those people would be complaining about really low brewhouse efficiencies. I voted over 95%, using kai's formulas with assumptions I'm typically 94-96%.

Link to Kai Troester's article on calculating conversion efficiency.

I agree with @pricelessbrewing & @chickypad that many people are either answering the poll with their mash efficiencies, or else they have really terrible conversion efficiency.

Brew on

 

[1MadScientist]

67.5% Rahr 2 row (3.5 EBC = 1.8 SRM) 4406 grams = 9.71 pounds
22.8% Wey Munich type 2 (25 EBC = 12.7 SRM) 1487 grams = 3.28 pounds
9.8% Crisp Caramalt (52 EBC = 26.4 SRM) 639 grams = 1.41 pounds

total 6.532 kg of grain with BIABacus default extract potential of 80% FGDB / 35.5 ppg


5.37 l/kg liquor to grain ratio (as displayed in Section W)

.8 [FGDB] / 5.37 [liters per kilogram ratio] + .8 [FGDB] = .1296 x 100 [FW max]

12.2 °P [FW measured] / 12.96 °P [FW max] = 94.1%

Efficiency into Boil = 79.9%

MS

 

[Biscuits]

I voted for 90-94..typically I'd say that is correct but I dip down into the mid to low 80's when I have grain bills with a lot of flaked malts.

 

[pricelessbrewing]

Actually, BrewersFriend uses the "correct" definition of "Conversion Efficiency"

"Conversion efficiency has been introduced to asses the performance of mash conversion before lauter losses take effect. Since it is difficult to measure the volume of wort in the mash, this efficiency is best assessed by calculating the highest possible mash wort gravity based on grist extract potential and mash water amount and then comparing the actual mash gravity to it. The mash gravity test for conversion efficiency allows brewers to troubleshoot low efficiency by determining if significant efficiency is lost during the mashing step."

Brew on ​

Welp, thanks for keeping me honest doug. Looks like I was mistaken from the last time I checked out their calculator.​

 

[doug293cz]

Welp, thanks for keeping me honest doug. Looks like I was mistaken from the last time I checked out their calculator.

To be honest, I just looked at their text. I didn't verify any results from their conversion efficiency calculator. My previous look at it made me think it might be a little flaky.

Edit: Well, I should have double checked the BrewersFriend Conversion Efficiency Calculator. Turns out the conversion efficiency calculations are Borked. Kai Troester, @pricelessbrewing 's calculator and my own spreadsheet all predict a maximum mash SG for 12 lb of 2-row mashed in 8.0 gal of water of 1.049. The BrewersFriend calculator predicts a maximum mash SG of 1.056. This is a huge error for this calculation.



Brew on

 

[Epos7]

Edit: Well, I should have double checked the BrewersFriend Conversion Efficiency Calculator. Turns out the conversion efficiency calculations are Borked. Kai Troester, @pricelessbrewing 's calculator and my own spreadsheet all predict a maximum mash SG for 12 lb of 2-row mashed in 8.0 gal of water of 1.049. The BrewersFriend calculator predicts a maximum mash SG of 1.056. This is a huge error for this calculation.

Wow, that's a pretty significant error. I've been using Brewer's Friend to calculate my conversion efficiency (just paid $15 for a subscription) so I wondered if my conversion efficiency is actually much higher than I've been calculating.

I haven't been using the Brewhouse Efficiency Calculator like you tested, rather I've been using the Brew Session tool. I tested this tool using the same parameters you used, and it output a conversion efficiency of 95.4%, so it would appear that the calculator they're using in the Brew Session tool is functioning correctly.

 

[1MadScientist]

Curious as to how you are determining the starting water volume (the full amount) as in a full volume mash.

What are your fixed values for these -
Boil time ?
Evaporation Rate ?
Grain Absorption ?

 

[Epos7]

Curious as to how you are determining the starting water volume (the full amount) as in a full volume mash.

What are your fixed values for these -
Boil time ?
Evaporation Rate ?
Grain Absorption ?

I'm still tweaking my equipment profile in Brewer's Friend, but my current values are:

Boil time - 60 for all recipes I've brewed except Munich Helles which was a 90 minute boil
Evaporation rate - 5.28 qt/hr
Grain absorbtion - 0.21 qt/lb

Evaporation rate has been tough to nail down. I'm constantly overshooting or undershooting my final volume. I'm less concerned about that right now and more concerned about getting my conversion efficiency to an acceptible level. As was discussed in my mill gap thread, I don't think the helical cutters on my current mill are a very good design. I'm considering contacting the manufacturer and asking to exchange the mill for a model with knurled rollers, and be refunded the difference.

 

[doug293cz]

Wow, that's a pretty significant error. I've been using Brewer's Friend to calculate my conversion efficiency (just paid $15 for a subscription) so I wondered if my conversion efficiency is actually much higher than I've been calculating.

I haven't been using the Brewhouse Efficiency Calculator like you tested, rather I've been using the Brew Session tool. I tested this tool using the same parameters you used, and it output a conversion efficiency of 95.4%, so it would appear that the calculator they're using in the Brew Session tool is functioning correctly.

It appears the Brew Session tool conversion efficiency calculator does not make a correction for grain moisture content (typically about 4%.) When I calculate for 12 lbs 2-row (1.037 potential, dry basis), 4% grain moisture content, 8 gal strike volume, and 100% conversion efficiency I get a wort SG of 1.0488. If I then set the grain moisture content to 0%, force the wort SG to 1.0488 and goal seek to determine the conversion efficiency, I get 95.4%! That's the same as BF calculates, so BF is not correcting for grain moisture content. This results in BF underestimating conversion efficiency.

Brew on

 

[1MadScientist]

Thanks Epos7.

Doug and Priceless ?

 

[pricelessbrewing]

It appears the Brew Session tool conversion efficiency calculator does not make a correction for grain moisture content (typically about 4%.)

Brew on

Yup I came to the same conclusion a bit ago and seemed to have forgotten. I just don't like their efficiency calculations. They're sloppy and not consistent.

@1MadScientist What's the question?

 

[1MadScientist]

Curious as to how you are determining the starting water volume (the full amount) as in a full volume mash.

What are your fixed values for these -
Boil time ?
Evaporation Rate ?
Grain Absorption ?

Edit:. Doug's screen shot and statement of 12# of grain mashed in 8 gallons. How did you come up with 8 gallons?

 

[Epos7]

It appears the Brew Session tool conversion efficiency calculator does not make a correction for grain moisture content (typically about 4%.) When I calculate for 12 lbs 2-row (1.037 potential, dry basis), 4% grain moisture content, 8 gal strike volume, and 100% conversion efficiency I get a wort SG of 1.0488. If I then set the grain moisture content to 0%, force the wort SG to 1.0488 and goal seek to determine the conversion efficiency, I get 95.4%! That's the same as BF calculates, so BF is not correcting for grain moisture content. This results in BF underestimating conversion efficiency.

Brew on

Aha, so my conversion efficiency may actually be ~4-5% higher than I've been thinking, thanks to Brewer's Friend's miscalculations. It looks like I need to switch calculators.

Now to figure out what the wort correction factor actually is on my refractometer For reference, it's a Milwaukee MA871.

I bought a 0-12 brix hydrometer to use for this purpose, and found that in RO water at 20C, it reads 0.5 brix. I then combined 20g of table sugar with 180g of RO water to make a 10 brix solution. In this solution my hydrometer read 10.2 brix.

Given these two data points, I worked out the following equation to convert my hydrometer measurement to its true value:

corrected value = (measured brix - 0.5) / 0.97

I brewed twice over the weekend, and took three wort measurements with both my hydrometer and refractometer. Note: my refractometer reads 0 on RO water.

Hydrometer 5.3 brix @ 22.8C
Temperature adjustment: 5.4
Corrected value = 5.05
Refractometer 5.3 brix @ 20.7C
Wort Correction Factor: 1.05

Hydrometer 7.8 brix @ 23.9C.
Temperature adjustment: 7.95
Corrected value = 7.68
Refractometer 7.8 brix @ 20.6C
Wort Correction Factor: 1.02

Hydrometer 10.2 brix @ 22.8C
Temperature adjustment: 10.3
Corrected value = 10.1
Refractometer 10.1 brix @ 20.8C
Wort Correction Factor: 1.0

So either my sucrose solution wasn't a true 10 brix solution, or the wort correction factor of my refractometer decreases with higher sugar concentrations. I'm confident that my measurements for making the solution were correct, but it's possible that my table sugar wasn't 100% sucrose.

Note: I used the Brewer's Friend hydrometer temperature adjustment calculator. Maybe not the most reliable source given the earlier findings.

Note note: I need to double check the water temperature for the 0 reading on my hydrometer.

 

[stever1000]

I need to do the same as you did to find the correction factor

 

[stever1000]

Looks like it to me too, otherwise all those people would be complaining about really low brewhouse efficiencies. I voted over 95%, using kai's formulas with assumptions I'm typically 94-96%.

Could you describe your process in detail? I'm amazed at your high efficiency

 

[Biscuits]

Brewed today and using doug239cz's calculations I hit 91% conversion efficiency, which is right where I expected it to be with the amount of flaked oats/barley that I had in the grist.

 

[doug293cz]

Brewed today and using doug239cz's calculations I hit 91% conversion efficiency, which is right where I expected it to be with the amount of flaked oats/barley that I had in the grist.

Can you link to the calculation instructions that you used? I don't think I posted any real calculation instructions in this thread? And if you just followed one of my links to Kai Troester's instructions, you should give Kai credit, not me. I learned a lot from Kai that I apply in many of my posts. Some of my analyses are original (as far as I know), but most are based on work done by many others over the years.

Brew on

 

[chickypad]

Could you describe your process in detail? I'm amazed at your high efficiency

Make sure to read through all the info linked in this thread, we are talking about conversion efficiency here. With good mash conditions, conversion efficiency over 90-95% should be the norm. My mash efficiency is more in the 78-79% range for average beers.

 

[stever1000]

Make sure to read through all the info linked in this thread, we are talking about conversion efficiency here. With good mash conditions, conversion efficiency over 90-95% should be the norm. My mash efficiency is more in the 78-79% range for average beers.

Time for more reading, thanks for the heads up

 

[Biscuits]

Can you link to the calculation instructions that you used? I don't think I posted any real calculation instructions in this thread? And if you just followed one of my links to Kai Troester's instructions, you should give Kai credit, not me. I learned a lot from Kai that I apply in many of my posts. Some of my analyses are original (as far as I know), but most are based on work done by many others over the years.

Brew on

Well, if we are going to get technical, which I know you love to do...I used the formulas you and @pricelessbiab use on his website. Except, I also incorporated the sugar yield for each grain similar to how beersmith does. It is sort of a hybrid that I created.

 

[stever1000]

I'm having trouble understanding how to calculate mash efficiency and conversion efficiency

Can someone break down the formulas a bit more?

My CE ,according to the link, (with CWact=1.040 and CWmax=1.047 ) is 83% which is bad, leading me to be more confused with my process...

I think my lauter efficiency is (no sparge, squeeze) LE=Pre-boil volume/(preboil volume + grain absorption) = 91%

How do I calculate mash efficiency

Brewhouse eff = CE*LE = 76%? which is not good
Is this right?

 

[pricelessbrewing]

Curious as to how you are determining the starting water volume (the full amount) as in a full volume mash.

What are your fixed values for these -
Boil time ?
Evaporation Rate ?
Grain Absorption ?

Edit:. Doug's screen shot and statement of 12# of grain mashed in 8 gallons. How did you come up with 8 gallons?

12 grains is what's needed to get a "typical" gravity of 1.055-1.065 for typical mash efficiencies.

Grain absorption is pretty much stuck to 0.08 gal/lb for almost all biabers I know that squeeze. There's a couple people that claim lower values, but I've pressed pretty dang hard and thinned out my grain bag across a wide surface and pressed and barely got anything additional from it so I feel pretty confident on a low Std dev for that value.

Evaporation rate will of course vary for a lot of brewers, but it's usually 1-1.15 gal for a 5 gallon batch.

Boil volume is pretty standardized at 5.5 gallons post boil volume, or VIF for you biabacuser's

Boil duration is pretty standardized at 60 minutes, some do less, some do more but the vast majority of recipes state 60 minutes.

So that gives somewhere between 7.5-8.1 gallons for most brewers. I would use 7.5-7.75 for an average brewer.

You'll obviously need more if you leave wort in the kettle after the wort is chilled.

 

[1MadScientist]

VFO is our post boil volume.

Using your defaults, I come up with a 1.057 OG. Very doable.

Our grain absorption very closely matches.

Here is a screenshot of a part of the BIABacus, for this discussion.

EDIT - Well the app won't allow an attachment, wants me to login, yet I'm logged in, hmm.

 

[1MadScientist]

MS screenshot

View attachment 1478365656571.jpg

 

[Epos7]

I attempted to contact Brewer's Friend on Thursday regarding the conversion efficiency discrepancies brought up in this thread, but didn't receive a reply.

 

[doug293cz]

I attempted to contact Brewer's Friend on Thursday regarding the conversion efficiency discrepancies brought up in this thread, but didn't receive a reply.

Where did you find contact information? I looked, but failed to find any.

Brew on

 

[Epos7]

They have a contact form I filled out. I think you may need a (free) account to access it.

http://www.brewersfriend.com/feedback-welcome/

 

[doug293cz]

They have a contact form I filled out. I think you may need a (free) account to access it.

http://www.brewersfriend.com/feedback-welcome/

I've seen that page before, but is doesn't seem to have any useful links. Perhaps because I do not have a paid membership. (Maybe they ought to pay me to help them fix their borked calculators. )

Brew on

 

[stever1000]

I'm having trouble understanding how to calculate mash efficiency and conversion efficiency

Can someone break down the formulas a bit more?

My CE ,according to the link, (with CWact=1.040 and CWmax=1.047 ) is 83% which is bad, leading me to be more confused with my process...

I think my lauter efficiency is (no sparge, squeeze) LE=Pre-boil volume/(preboil volume + grain absorption) = 91%

How do I calculate mash efficiency or is it the same as below? I have seen both
Brewhouse eff = CE*LE = 76%? which is not good
Is this right?

Bump

 

[pricelessbrewing]

VFO is our post boil volume.

From what I recall, VFO is the still hot volume, and VIF is the chilled volume - kettle losses right? If so that's what I was using, the chilled volume.

 

[Epos7]

I've seen that page before, but is doesn't seem to have any useful links. Perhaps because I do not have a paid membership. (Maybe they ought to pay me to help them fix their borked calculators. )

Brew on

Even if you have a paid membership it doesn't appear they actually reply. What a waste of $15.

Oh well, I'll switch to a different calculator moving forward.