Marginal Brew House Efficiency

[Hwk-I-St8]

I've brewed two all grain batches and had the nearly the same brew house efficiency...61%. I use Brewer's Friend to track my recipes and sessions. Here is the info I collected on the last batch (I don't have as detailed data on the first one).

Strike Volume: 4.5 G
Sparge Volume: 3.8 G
First Runnings volume: 2.5 G
Second Runnings volume: 3.75 G

Pre-boil gravity: 1.047
Post boil gravity: 1.060 (was shooting for 1.069)

BF says 80% efficiency on the mash and the 61% brewhouse. Sure enough, I dropped the efficiency calc on the recipe to 60% and the gravities are spot on.

I use a rectangular cooler and nailed my mash temp of 152 within 0.3 degrees. Mashed for an hour. PH was 5.29. I did not check the wort with iodine, but after a week in the ferm my gravity is 1.016, so I think I had full conversion.

With 8.3 gallons in and 6.25 out, I feel like grain absorption and equipment loss is the issue, but cleaning out the tun there really wasn't much liquid left in the cooler, but I lost two gallons there. Grain bill was 14.88 lbs.

The one thing that strikes me is the disparity in volume between first and second runnings...a thinner mash might help (I planned 1.25 qts/lb).

I'm new to this. What, if anything, can I do to increase my overall efficiency? I can just up my grain bill to compensate, it's probably only $5, but if there's something I can do to improve this, I'm interested in refining the process.

 

[wilserbrewer]

How's your crush?

Your water loss due to absorption is high, do you have a lot of dead space in your cooler? Did you let it fully drain and drip for 10-15 minutes, or just cut it when it first stopped.

I let my cooler continue to drip
One brew session and I was amazed how much more wort fell out over time. But this is second runnings, so my first intuition is crush.

 

[pricelessbrewing]

Need the recipe as well.

 

[mongoose33]

I almost always get the same volume of second runnings as my sparge volume. Makes sense if you think about it: the grain has absorbed all the water it's going to, so the sparge just passes through.

Your grain bill is fairly high; one rule of thumb is that you lose an eighth of a gallon of water per pound of grain--or 1/2 quart per pound. So you would have had roughly 1.85 gallons of absorption. The rest could be equipment loss, spillage, and not fully draining the grain. So I don't see it as being all that unusual.

In a typical grain bill of 12 pounds for me, I'll draw off about 2 3/8 gallon on first runnings, then 4 gallons (what the sparge is) on second runnings. That's with 8 gallons or if I'm feeling expansive, 8.25 gallons.

I'm with Michael: how's your crush?

 

[Hwk-I-St8]

Crush is always the question, right? I was hoping that I provided enough info to identify if it was a crush issue. I don't own a mill, so it's a LHBS crush.

 

[mongoose33]

Crush is always the question, right? I was hoping that I provided enough info to identify if it was a crush issue. I don't own a mill, so it's a LHBS crush.

Well, yes, crush almost always is the question. It's the first place to start w/r/t efficiency.

It is said that a LHBS often will give a coarser crush so as to reduce the chances of a stuck sparge. It also coincidentally means that one must buy a bit more grain to get the same efficiency.

 

[Hwk-I-St8]

How's your crush?

Your water loss due to absorption is high, do you have a lot of dead space in your cooler? Did you let it fully drain and drip for 10-15 minutes, or just cut it when it first stopped.

I let my cooler continue to drip
One brew session and I was amazed how much more wort fell out over time. But this is second runnings, so my first intuition is crush.

First runnings we stopped as soon as it stopped, put that on to begin the boil. For the sparge, we shut the valve, waited about 20 minutes, then opened the valve and got close to another quart. We have curbside composting so I saved the spent grains in a bag. There really wasn't much liquid in there...maybe a quart after it sat for an hour or so. I don't feel like I have a huge dead space issue, but I'm guessing it's more than you'd have from a beverage cooler with a false bottom and dip tube.

 

[doug293cz]

Your numbers don't look to be self consistent. The maximum theoretical mash efficiency (and lauter efficiency) with equal runnings, single batch sparge for 6.25 gal pre-boil volume, 8.3 gal total brewing water, and 14.88 lb of grain is 76.27%, and should give a pre-boil SG of about 1.064. Not sure what numbers you put into BF, but there is no way your mash efficiency was anywhere near 80%.

You don't give a post-boil volume, but if we assume that you had a boil-off of 1 gal, and a post-boil volume of 5.25 gal, we can estimate your conversion efficiency and your lauter efficiency (mash efficiency = conversion eff * lauter eff) by using your OG (post-boil SG.) I'll explain in a bit why we aren't using your pre-boil SG. Plugging everything into the simulator we get:

Conversion efficiency: 77%
Lauter efficiency: 77 - 78%
Mash efficiency: 59 - 60%
Pre-boil SG: 1.050 - 1.051
OG: 1.060​

Your measured pre-boil SG of 1.047 is significantly lower than the 1.050-1.051 that is needed to make your numbers self consistent. This can happen if you don't adequately mix your first and second runnings (it takes way more mixing than you think it should to homogenize the total wort volume.)

If you had gotten 100% conversion efficiency, then your results would have looked more like this:

Conversion efficiency: 100%
Lauter efficiency: 76% (yes, strangely enough lauter eff drops when conv eff goes up)
Mash efficiency: 76%
Pre-boil SG: 1.064
OG: 1.076​

My conclusion is that your conversion efficiency was very low (good is 95% or better.) This is usually due to too coarse a crush, and/or too short a mash time.

Your run-off volume ratio did not significantly affect your lauter efficiency. But, your mash thickness was only 1.21 qt/lb, which is kind of low. Kai Troester has shown that thinner mashes convert faster than thicker mashes, and thus can help you get closer to 100% conv efficiency. In addition to exploring finer crush you might want to look at mash thickness more in the 1.5 - 1.75 qt/lb range in order to improve your conversion efficiency.

Brew on

 

[madscientist451]

What was your volume to the fermenter? Did you measure the gravity of the final runnings?
Also chiming in need the complete recipe, and what mashing procedure? Batch sparge?
Fly sparge? Any re-circulation? Speed of runoff? All these variables can have an impact on gravity and efficiency.

 

[Hwk-I-St8]

Your numbers don't look to be self consistent. The maximum theoretical mash efficiency (and lauter efficiency) with equal runnings, single batch sparge for 6.25 gal pre-boil volume, 8.3 gal total brewing water, and 14.88 lb of grain is 76.27%, and should give a pre-boil SG of about 1.064. Not sure what numbers you put into BF, but there is no way your mash efficiency was anywhere near 80%.

You don't give a post-boil volume, but if we assume that you had a boil-off of 1 gal, and a post-boil volume of 5.25 gal, we can estimate your conversion efficiency and your lauter efficiency (mash efficiency = conversion eff * lauter eff) by using your OG (post-boil SG.) I'll explain in a bit why we aren't using your pre-boil SG. Plugging everything into the simulator we get:

Conversion efficiency: 77%
Lauter efficiency: 77 - 78%
Mash efficiency: 59 - 60%
Pre-boil SG: 1.050 - 1.051
OG: 1.060​

Your measured pre-boil SG of 1.047 is significantly lower than the 1.050-1.051 that is needed to make your numbers self consistent. This can happen if you don't adequately mix your first and second runnings (it takes way more mixing than you think it should to homogenize the total wort volume.)

If you had gotten 100% conversion efficiency, then your results would have looked more like this:

Conversion efficiency: 100%
Lauter efficiency: 76% (yes, strangely enough lauter eff drops when conv eff goes up)
Mash efficiency: 76%
Pre-boil SG: 1.064
OG: 1.076​

My conclusion is that your conversion efficiency was very low (good is 95% or better.) This is usually due to too coarse a crush, and/or too short a mash time.

Your run-off volume ratio did not significantly affect your lauter efficiency. But, your mash thickness was only 1.21 qt/lb, which is kind of low. Kai Troester has shown that thinner mashes convert faster than thicker mashes, and thus can help you get closer to 100% conv efficiency. In addition to exploring finer crush you might want to look at mash thickness more in the 1.5 - 1.75 qt/lb range in order to improve your conversion efficiency.

Brew on

The numbers I put into BF are what I posted here. It said 80% conversion efficiency...not me. I have the data collected, but have not tried to calculate anything from it.

 

[pricelessbrewing]

Brewhouses conversion formula is wrong. It uses wort gravity but strike water volume which assumes the sugar converted occupies no additional volume.

 

[doug293cz]

Brewhouses conversion formula is wrong. It uses wort gravity but strike water volume which assumes the sugar converted occupies no additional volume.

Don't you mean Brewer'sFriend? I agree that their conversion efficiency formula is wrong.

Brew on

 

[pricelessbrewing]

Don't you mean Brewer'sFriend? I agree that their conversion efficiency formula is wrong.

Brew on

Stupid autocorrect. Yeah, that one.

 

[ba-brewer]

I know there are plenty of people that say their conversion is done in 20 or 30min but sometimes it takes longer than 60min to complete the conversion. It is better to check the gravity of the mash against the expected gravity before pulling the first runnings then just going on a set time. I use a refractometer to check the conversion.

You can use the batch sparge parti gyle simulator in this link to calculate the expected gravity of your runnings.
http://www.braukaiser.com/wiki/index.php?title=Tables_for_Conversions_and_Calculations

 

[RM-MN]

I know there are plenty of people that say their conversion is done in 20 or 30min but sometimes it takes longer than 60min to complete the conversion. It is better to check the gravity of the mash against the expected gravity before pulling the first runnings then just going on a set time. I use a refractometer to check the conversion.

You can use the batch sparge parti gyle simulator in this link to calculate the expected gravity of your runnings.
http://www.braukaiser.com/wiki/index.php?title=Tables_for_Conversions_and_Calculations

I'm one of those who claim conversion in 20 to 30 minutes but it is because of my very fine milling and often it will take 60 minutes or longer for the crush you get from the LHBS, some times much longer. For about $10 you can get a bottle of iodine from the pharmacy and have the means to tell if your conversion is complete. Make sure when you take the sample you have plenty of grain particles in that sample and if your iodine turns any of them blue you have your answer, incomplete conversion. Try doing a 90 to 120 minute mash sometime and see if your efficiency goes up.

 

[ba-brewer]

When I first tried to dial in my efficiency I did the the iodine test, but was never to quite sure about the results. I thought I read to try avoid getting grain pieces when doing a iodine test, but your comments sort of makes sense too. I had a refractomer and that seemed to work easier than messing with the iodine. My first refractometer was a little over $20.

I mill my own grain and don't mess with the setting and still get variation in conversion times. It seemed like a month back everything was taking just a bit longer, closer to 90min to get above 90%. Yesterday I did a batch and it was 89% converted in 25min. If I would have just drained at 60min a month ago the conversion would of been closer to 80% and my efficiency would have suffered.

 

[pricelessbrewing]

Conversion rate (% vs time) is a function of crush, dough in process, mash temp, and pH.

Finer the crush, the faster the gelatinization, hence the faster the extraction and conversion.

The better you stir in, or recirculate, the faster the gelatinization and thus the extraction and conversion.

Low mash temps generally take longer, and too high will cause it occur more quickly but might cause the enzymes to denature before full conversion is reached.

Too low <5.2, or too high >5.6 and conversion won't go very well either.

If all the parameters are good, it should occur before 45 minutes. If it's taking longer than 45 minutes, I would suggest looking at each of those.

<30 minutes is going to require ALL of them to be in a small ideal range.

 

[SteveHeff]

I see a lot of information here, but there is one thing that hasn't been addressed. That is your mash tun. Rectangular coolers typically have a lower efficiency than a taller pot. From several reputable sources (none of which I can link to), if you alter the mash tun, your efficiency will improve.

I have been using my rectangular cooler for 5 years and I'm disappointed every time my efficiency is lower than I hope for, although I know what to expect now. I don't brew enough to buy or build a new mash tun. The cost of tossing in 1-2 lbs of LME is worth it, to me. Short story long: I have the same efficiency issues but I correct using late addition LME.

 

[pricelessbrewing]

I see a lot of information here, but there is one thing that hasn't been addressed. That is your mash tun. Rectangular coolers typically have a lower efficiency than a taller pot. From several reputable sources (none of which I can link to), if you alter the mash tun, your efficiency will improve.

I have been using my rectangular cooler for 5 years and I'm disappointed every time my efficiency is lower than I hope for, although I know what to expect now. I don't brew enough to buy or build a new mash tun. The cost of tossing in 1-2 lbs of LME is worth it, to me. Short story long: I have the same efficiency issues but I correct using late addition LME.

This is only true if you fly sparge, and is due to channeling. Not applicable to no-sparge or batch sparge.

 

[doug293cz]

I see a lot of information here, but there is one thing that hasn't been addressed. That is your mash tun. Rectangular coolers typically have a lower efficiency than a taller pot. From several reputable sources (none of which I can link to), if you alter the mash tun, your efficiency will improve.

...

This is only (potentially) true for fly (continuous) sparging. A rectangular cooler with no channeling during sparge will still do better than a taller cylindrical vessel that does exhibit channeling.

For batch (or no) sparging, MLT geometry doesn't matter, except for any undrainable volume. The conversion process is independent of geometry, as long the grain isn't constrained to too small a fraction of the total (grain + water) mash volume. Lauter efficiency is decreased with increasing undrainable (dead) volume, with zero undrainable being optimal. Batch sparging has been modeled by Kai Troester, and I have independently duplicated and verified that model.

Edit: Damn! @pricelessbrewing , you beat me to it. That's what I get for being too wordy.

Brew on

 

[Hwk-I-St8]

This is only (potentially) true for fly (continuous) sparging. A rectangular cooler with no channeling during sparge will still do better than a taller cylindrical vessel that does exhibit channeling.

For batch (or no) sparging, MLT geometry doesn't matter, except for any undrainable volume. The conversion process is independent of geometry, as long the grain isn't constrained to too small a fraction of the total (grain + water) mash volume. Lauter efficiency is decreased with increasing undrainable (dead) volume, with zero undrainable being optimal. Batch sparging has been modeled by Kai Troester, and I have independently duplicated and verified that model.

Edit: Damn! @pricelessbrewing , you beat me to it. That's what I get for being too wordy.

Brew on

This, along with convenience and expediency, are why I batch sparge.