Another Efficiency Issue...

[dnye]

Hi all, I've done about 5 or so brews on my new BIAB system and seem to be consistently getting low numbers and am trying to trace down the cause.
I know the first response is always on the crush. I am getting it from the LHBS and in the order I put comment to crush at 1.026 which they promise they do. The grain looks quite crushed with a good bit of flour at the bottom of the bag, so I don't immediately think this is my issue, but don't know what else it could be.

My set up is a Spike 10 gallon kettle with electric heating element and false bottom from brewHardware. I'm using an inkbird to maintian mash temps and recirculate with a pump during mash as well as stirring occasionally. Then after mash suspend bag over a bucket and squeeze to try and get as much liquid out of the bag as possible and add back to the pot, but no sparge.

This recipe from the most recent brew is:
10# German Pilsner
0.25# Melanoidin Malt
0.5# Carapils

I started with 7.75 gallons of water. After the mash at 148 for 80 min(and adding back all the drips from the bag), I had 6.75 gallons left at about 1.035 (measured with refactometer). After 60 min boil I was left with 5.5 gallons at 1.045. Target OG was 1.055.

According to brewers friend this gives 67% conversion efficiency and 60% ending kettle.

I'm using tap water that has been run through a filter, but is otherwise untouched. So water chemistry is my first thought, but not sure how much impact this would have?

Any ideas on what could be causing the low numbers would be much appreciated.

 

[McKnuckle]

This is a tough one on first blush. I plugged your numbers into my brewing tools, and you had a 0.093 gal/lb absorption rate which is typical for squeezed BIAB. I also see 67% conversion efficiency. There seems to be nothing wrong with your physical process.

There's always a chance that you didn't mix well and got an inaccurate pre-boil gravity. We can check that using your OG: You boiled off 1.25 gallons and ended with 1.045. Using that to retroactively calculate pre-boil gravity, it would be 1.037. So slightly higher but still very disappointing.

So that leaves crush and mash pH as suspects.

The light colored grain bill has very little acidity, so if the water has high alkalinity, that could cause an unacceptably high mash pH. I don't know how much impact that would have to the extent of killing your conversion so much. But it's probably the key culprit.

You might take a photo of the crush just to get some opinions (if you captured one).

 

[Thinredline87]

The light colored grain bill has very little acidity, so if the water has high alkalinity, that could cause an unacceptably high mash pH.

Does this apply to all light grains or are specific grains more susceptible. For example is 2 row not so bad and Marris Otter is?

 

[Oginme]

So the first thing to look at is definitely the crush. Next batch of grain you get crushed, take a 1/3 cup measuring scoop and blindly remove a full scoop of the grain. Spread it on a cookie sheet with edges and look for kernels which are apparently intact. You should have very few of these and finding them does not mean they are not crushed. Remove a few and squeeze them between your fingers. If they are cracked at all, they should splinter easily. If they are hard and do not splinter, then they are uncrushed kernels and will not yield up their starches easily.

Assuming that the kernels are well crushed, the next thing to look at is your doughing in process. How long are you stirring the grains and making sure they are fully wetted? I stir while slowly pouring the grain into the strike water and then for a minimum of 5 minutes after the grains have been fully added. If I see any dough balls or even small clumps of grains, I stir longer to make sure these get broken up and thoroughly wet the grain particles.

With your water chemistry, it will make a difference in how well the enzymes work. When you say you filter the water, does this mean through a RO system, or just a particle filtration? If you are producing RO, then I would recommend a water program to help with mineral additions for flavor and possibly acid to control your mash pH. If it is just a particle filtration, then you would need to know the chemistry of your tap water before making any meaningful additions.

 

[McKnuckle]

Does this apply to all light grains or are specific grains more susceptible. For example is 2 row not so bad and Marris Otter is?

It's a general concern for lightly colored malts, with insignificant variation based on grain type.

The more lightly kilned the grain, the less acidity it has to counter alkalinity. Brewing water for light beers can be low in mineral content (i.e. classic Czech Pilsner is alleged to be brewed in very soft water), but it can't have high alkalinity. You need to acidify such water to cut that alkalinity and get mash pH in the right range.

 

[dnye]

I assume the best way to figure out if it a pH issue is to measure the water I'm using correct? Is this just done with a pH meter? I've seen people talk about getting their water tested is there a best test kit for brewing?

 

[eric19312]

I assume the best way to figure out if it a pH issue is to measure the water I'm using correct? Is this just done with a pH meter? I've seen people talk about getting their water tested is there a best test kit for brewing?

Start with a water report from your local water authority. Plug the numbers into Brewer’s Friend to see in broad terms what you are dealing with. If it looks like adjustments are called for give them a try. Ideally you get a pH meter accurate to 0.01 and measure pH of a sample of your mash, collected about 20 min after dough in, and cooled to room temperature before measuring. But without a meter see if the calculator recommends an adjustment and consider giving it a try.

 

[Oginme]

The pH of your water source means very little. You need a water report on the mineral content with specifically Calcium, Magnesium, Chloride, Sulfate, Sodium, Total Alkalinity, and Total Hardness as a minimum.

 

[LittleRiver]

It sounds like you are serious about this hobby. I recommend that you make getting your own grain mill a priority. It's a modest investment you'll never regret. You can remove all doubt about how well your grain is being crushed.

 

[McKnuckle]

You're getting some various advice (welcome to HBT ) which is helpful, but confusing.

The first thing to do is to evaluate your water. You don't measure the water's pH. You should send a sample to Ward Labs and request a brewing report. This will tell you the concentration of the key brewing ions, including the all-important alkalinity figure. That is the main factor that may be killing you here.

We didn't touch on whether you have a water softener in your house. That's another no-no if you do. It adds lots of sodium to the water.

Regarding a mill; it's an awesome thing to have, but not #1 to consider here. Even with a reasonable but not ideal crush, you'd do way better than 67% conversion.

 

[dnye]

I certainly understand the opinion of the grain mill. I'm trying to avoid it as it just seems like a hassle to have around. I'd rather just use the brew store as long as I can get it consistent I don't mind have to pay an extra buck for the extra grain, but the crush I'm getting doesn't seem too bad. I agree with McKnuckle that with the crush I'm getting I think I should be able to be slightly better. I don't have to be at 95% just want to be consistent, but would love to be a little higher.

Sounds like I'll start with the Ward labs analysis and see what it says.

oh and no water softener in the house.

Thanks for all the replies!

 

[RM-MN]

[My opinion only]

If you are able to recirculate the wort during the mash without overflowing somewhere, look to the crush as the problem area. A fine crush contains so many small particles that they tend to clog the pores of the grain bag and cause it to overflow.

 

[eric19312]

Sounds like I'll start with the Ward labs analysis and see what it says.

I was going to say again to look online for a water report that would point you in the right direction but I see you are in Ohio and it seems the water authorities in Ohio are giving you the minimum EPA required reporting which isn't helpful for brewing. You probably would benefit from sending a sample to Ward but you might also check with other local homebrewers or even breweries if any in your area using same water you are brewing with.

From what reports I did read it sounds like Ohio can have pretty hard water and that if you are in major metropolitan area like Columbus the city is most likely softening the water they are delivering to you. Only problem with the Ward labs report is that is at one point in time. It doesn't necessarily tell you much about the water you are brewing with today. Back to asking around, especially a helpful professional brewer could give you some insight on how much the water changes from season to season or even day to day in your area. If the answer is not much, then the Ward report should be all you need. If the answer is it is changing all the time, not predictable, all over the place...then you really might want to consider getting an RO system before that grain mill.

 

[wilserbrewer]

My best guess here...just because you put a comment w/ your order to crush at 1.026 (shouldn’t this be 0.026 ???)

Doesn’t give me much confidence that you actually got a decent crush...call me a skeptic.

Post a pic of your crush before going further into this investigation please.

148 is the lower end for a mash temp...
Was this confirmed with an accurate thermometer stuck in the mash, or is this what your new BIAB system inkbird display read? Did you check temps against another known working thermometer?

Where is your temp sensor probe located?

 

[jtratcliff]

Efficiency issues with BIAB are almost always 99% crush...

Crush till you're scared... Then crush some more...

If using LHBS crush, then run it through the mill twice (double crush) ...

 

[Gnomebrewer]

Where in Ohio are you? There are many water reports listed here
https://www.brewersfriend.com/homebrew/water-profiles
with major centres in Ohio mostly falling between 50 and 100ppm alkalinity (the most important water factor, which leads to a high pH). That's a moderate amount, that can be worked with, but would have led to a high mash pH in a pale beer with no acid.
You had a low mash temperature, which favours beta-amylase, but beta-amylase likes a low pH. You also had a thin mash, which (all else being equal) slows down conversion (less random chance of an enzyme meeting with a starch). Your crush was somewhere above 0.026" (which is coarse by BIAB standards). This is all going to lead to slow conversion. Something that few brewers do, that can really help, is to measure your mash gravity so that you know it has finished. Use the mash conversion section from the spreadsheet here
http://braukaiser.com/documents/efficiency_calculator.xls
If your mash conversion isn't near 100%, keep mashing! (don't worry about how long the recipe says to mash for, go until it's completed). Get your pH and crush in order, and you'll hit that 100% efficiency much faster. FWIW, next time you brew a pale beer, try replacing 3% of your grist with acid malt.

 

[dnye]

yeah sorry, meant 0.026. Don't have a picture of the crush. Profile says Ohio, but actually moved to Michigan, just am still in denial.

Yeah I mean I always hear the crush is the first place to look, but mine didn't look too bad. I guess I can try for a better crush next time as well as look into water. Maybe order from Bobby, his picture the other day of his crush looked quite good, just amazon has made me way less happy about having to actually pay for shipping....

 

[LittleRiver]

...Maybe order from Bobby, his picture the other day of his crush looked quite good...

I've never ordered grain from Bobby, but if the experience is anything like ordering hardware from him you won't find a better supplier.

...amazon has made me way less happy about having to actually pay for shipping....

I know you've said you don't want to get a mill, but I would be remiss if I didn't point out that it's your best option, especially if you like the hobby and plan to stay with it. That is true financially, and functionally.

A Cereal Killer is $99, that includes shipping and a mounting plate. Get yourself a 5gal bucket for $4.48, and a set of feeler gauges for $7.59, and you are good to go. The bucket will probably fit inside your kettle for storage between brews.

Buy your base grain in bulk, and you'll save money on grain costs. If you can pick up that sack when you are near a homebrewing store, you won't have to pay shipping. You also won't be paying for shipping grain every time you brew. You'll probably save more than the cost of the grain milling rig in the first year. You'll gain control and consistency in your crush, which will help you sort out your efficiency issues.

 

[rjdutch]

If you live in Michigan I'd bet you have high alkalinity. I know I do. And it will effect your efficiency. Getting your water tested for brewing is a great call. Then you know for sure where you're starting as far as water profile.
The crush is also critical. I have a mill and always double crush. Sometimes I panic when it looks like I made flour but so far no stuck mash.

 

[Oginme]

yeah sorry, meant 0.026. Don't have a picture of the crush. Profile says Ohio, but actually moved to Michigan, just am still in denial.

Yeah I mean I always hear the crush is the first place to look, but mine didn't look too bad. I guess I can try for a better crush next time as well as look into water. Maybe order from Bobby, his picture the other day of his crush looked quite good, just amazon has made me way less happy about having to actually pay for shipping....

Mine did not look bad at all at first glance, then I did the full kernel screening and discovered that I had more than a dozen uncrushed, unbroken kernels in every half cup. This adds up pretty fast when you are looking at a 5-gal bucket half full of crushed grains.

 

[Soyben]

Your numbers a very similar to mine before I got a grain mill. I would typically be around 67% no sparge. If I wanted better efficiency I would just sparge in a second pot with 1 to 2 gallons of water as my kettle was coming to a boil, that would up my efficiency another 6-8% getting to around 75%. Typically if I was only doing a 5 gallon batch I would just buy a little more grain. That would add about $2 to a batch, no big deal. Also any batches I did with a large amount of wheat, my efficiency would go down due to the smaller kernel size.

I kind of doubt your LHBS is adjusting their mill. I asked mine once where it was set, they replied it was locked down and were not sure. Asking for a double crush my be more productive. My gravity numbers became much more consistent with my own mill.

 

[doug293cz]

... You also had a thin mash, which (all else being equal) slows down conversion (less random chance of an enzyme meeting with a starch). ...

Not according to Braukaiser's testing. Kai found that thin mashes actually convert faster. There are other factors that are more important than the enzyme concentration.

Brew on

 

[Gnomebrewer]

Not according to Braukaiser's testing. Kai found that thin mashes actually convert faster.

I really enjoy reading some of Kai's work (I use his spreadsheet for all of my efficiency calculations), but also find some things a bit misleading. I'm not saying he's necessarily wrong with his conclusion (and maybe thin mashes do convert faster, I'm only going by something I ready as an early brewer that a normal mash thickness is faster, I can't even remember where I read it) however, his conclusion can't be determined from his results....
If you read the study that was done comparing the mash thicknesses, the only results that were collected were the limit of attenuation and efficiency (using no-sparge) resulting from mashes at different thicknesses. He doesn't show any data for the time taken for conversion at different thicknesses. I'm also a bit perplexed as to why he'd measure efficiency using no-sparge with different mash thicknesses - of course the thinner mash will be more efficient!

There are other factors that are more important than the enzyme concentration.

Absolutely. A fine crush will be streets ahead of all others. But if the OP can't control crush, 100% (or close to) conversion efficiency can still be reached if other factors are well managed and mash conversion is measured (provided there aren't too many completely un-crushed grains).

 

[soccerdad]

I read through this pretty quickly and saw no mention - other than your original post - of mash time. The guys over at biabrewer ( many of whom helped pioneer the method) will swear by a 90 minute mash minimum. You went 80 minutes, and that's darn close, but with the questions about crush and .026 being not all that fine ... you might just want to consider longer mash. The theory is pretty simple .. longer time allows more complete saturation which lends to more extraction. It's worth looking at IMO.

 

[Gnomebrewer]

... you might just want to consider longer mash. The theory is pretty simple .. longer time allows more complete saturation which lends to more extraction. It's worth looking at IMO.

For sure. If you can't control the crush, control the mash time. How long do you mash? At least until the mash is finished.

 

[soccerdad]

I like having a refractometer when I mash .. just for that reason. Helps to know if the mash is done. Or at least good enough for who it's for.

 

[doug293cz]

I really enjoy reading some of Kai's work (I use his spreadsheet for all of my efficiency calculations), but also find some things a bit misleading. I'm not saying he's necessarily wrong with his conclusion (and maybe thin mashes do convert faster, I'm only going by something I ready as an early brewer that a normal mash thickness is faster, I can't even remember where I read it) however, his conclusion can't be determined from his results....
If you read the study that was done comparing the mash thicknesses, the only results that were collected were the limit of attenuation and efficiency (using no-sparge) resulting from mashes at different thicknesses. He doesn't show any data for the time taken for conversion at different thicknesses. I'm also a bit perplexed as to why he'd measure efficiency using no-sparge with different mash thicknesses - of course the thinner mash will be more efficient!



Absolutely. A fine crush will be streets ahead of all others. But if the OP can't control crush, 100% (or close to) conversion efficiency can still be reached if other factors are well managed and mash conversion is measured (provided there aren't too many completely un-crushed grains).

Yeah, I reread Kai's writings, and they are a bit sloppy. He quotes Briggs for thin mashes being faster to convert than thick mashes. but the data he presents is labeled incorrectly. I did a calculation of lauter efficiency assuming 100% conversion efficiency for 1.21 & 2.37 qt/lb mash thickness (assuming 0.12 gal/lb grain absorption) and the lauter efficiency difference was 22% (50.6% for thick and 72.6% for thin), so the chart that he labels "Brewhouse efficiency", which would be "mash efficiency" using the more common definitions (mash efficiency = conversion efficiency * lauter efficiency), cannot be mash efficiency since the difference is only 8%. Thus the the chart has to be for conversion efficiency, and if you get higher conversion efficiency in the same amount of time, the conversion rate has to be higher.

Brew on

 

[LittleRiver]

...The guys over at biabrewer ( many of whom helped pioneer the method) will swear by a 90 minute mash minimum.....

Along with a 90min mash I've also seen them recommend a coarse crush, advise against letting the bag fully drain into the kettle by gravity, and a few other things that just don't make sense. Just because they were the first doesn't make their way the "right" way.

A fine crush and 60min mash (or less) works, and works well. This has been proven many times over.

 

[soccerdad]

I apologize for making any suggestions.

 

[bracconiere]

I apologize for making any suggestions.

just wanted to say, LOL

edit: (and with my tap water, run through a econe hose filter...my mash ph measured, starts at 4.9-4.8, i have to add bicarb to get it up...otherwise my efficiency takes a nose dive...but i fly sparge)

 

[badmajon]

Hey, I used BIAB for 5 years and I always got about 67%. I got that when I lived in the UK with Lincolnshire water, and I got the same crappy figure when I moved to the suburbs of D.C. and used Potomac-sourced water.

Bad efficiency is a problem a lot of people experience with BIAB. It's way easier and less time consuming than mashing beer any other way, but you just have to pay more $ in the form of extra grain which ends up being only a few bucks anyway.

I know some people get efficiencies comparable to other methods, but unfortunately crap efficiency is a common BIAB experience that many people have not really been able to solve... even after getting the crush perfect and adjusting water profiles. Surely there is a scientific reason but AFAIK nobody has really figured it out yet.

 

[LittleRiver]

...Bad efficiency is a problem a lot of people experience with BIAB...have to pay more $ in the form of extra grain...crap efficiency is a common BIAB experience that many people have not really been able to solve... even after getting the crush perfect and adjusting water profiles...

I believe you when you said you had efficiency problems. I couldn't disagree with you more when you imply that is an inherent attribute of BIAB. There's just too much evidence otherwise for that to be true.

There's nothing special about me, I'm a run of the mill home brewer with far less experience than many of the folks on the forum, yet I get great efficiency with BIAB. I get low 80's without even trying hard.

I can consistently exceed recipe targets without adding extra grain, without sparging, and without squeezing the bag.

 

[Oginme]

I would contend that low efficiency is mostly a matter of crush and process. You can crush a finer to get more rapid solubility of the starches which helps with more efficient mobility of the starches and sugars into the water. After that it is how the brewer operates the process -- sifting grist into the water for better dispersion, stirring to eliminate dough balls, drainage (or squeezing) to maximize wort retrieval from the bag of grains, etc. With that you can throw in managing water quality and mash pH to maximize the conversion efficiency.

I shift back every once in a while to by mash tun traditional brewing rig, but take an efficiency hit from my BIAB which is how I make the majority of my recipes. Mash/lauter efficiency from BIAB 86% to 88%, from my mash tun system it is 78% to 81%. Main difference is the loss in the dead space of the mash tun and added wort loss in grain absorption.

I see no evidence that any loss is inherent to the BIAB process.

 

[soccerdad]

I personally think lower efficiency with BIAB is simply a myth. But that's just my opinion guided by experience. YMMV.

 

[jdauria]

Besides water which as everyone said you should look into, I question whether the shop actually crushed the gap you requested. My local shop does not move the mill setting...it's set for regular mash/sparge AG brewers to keep them from getting a stuck sparge. Before I got my own mill, I would double crush with their mill and would get 67% mash efficiency with BIAB. But then I started seeing half of the grain coming out of their mill uncrushed as the mill gap kept slipping. So I got my own mill, started at 0.035 and double crushed and starting getting 72-75% efficiency, then dropped it to 0.032 and was getting 78-80% efficiency. Lately, I have been conditioning my grain (spraying with a few ounces of water) waiting ten minutes, then single crushing my grain at 0.028. Doing that my mash efficiency jumped to 88-92%. I do use distilled water and adjust it.

 

[badmajon]

Sigh, I wish I could get those numbers. I recently did a recirculating fly sparge and got 78% which is the best I've ever had... except the first time I did BIAB. I got 85%. Then 65-67% for the next 5 something years.

 

[RM-MN]

Sigh, I wish I could get those numbers. I recently did a recirculating fly sparge and got 78% which is the best I've ever had... except the first time I did BIAB. I got 85%. Then 65-67% for the next 5 something years.

With that much change in efficiency I'd be looking hard for a cause and it wouldn't have taken 5 years. As mentioned above, the crush of the grain is the single biggest cause of poor efficiency followed by brewers practices of leaving the trub in the kettle and any left in chillers or tubing. If you are still relying on the LHBS to mill your grain, they are the ones to blame, followed by yourself for not dumping them and getting your own mill.

 

[Bill Huelsman]

A test kit for personal use is $300. Ward labs is $40

 

[Oginme]

Basic LaMotte kit is around $120. If your water supply varies throughout the year and you don't have ready access to municipal reports, it is a good value. If you are on a private water source (well) which is pretty stable, it is nice but more expensive than a Ward Labs test.

 

[pricelessbrewing]

Yeah, I reread Kai's writings, and they are a bit sloppy. He quotes Briggs for thin mashes being faster to convert than thick mashes. but the data he presents is labeled incorrectly. I did a calculation of lauter efficiency assuming 100% conversion efficiency for 1.21 & 2.37 qt/lb mash thickness (assuming 0.12 gal/lb grain absorption) and the lauter efficiency difference was 22% (50.6% for thick and 72.6% for thin), so the chart that he labels "Brewhouse efficiency", which would be "mash efficiency" using the more common definitions (mash efficiency = conversion efficiency * lauter efficiency), cannot be mash efficiency since the difference is only 8%. Thus the the chart has to be for conversion efficiency, and if you get higher conversion efficiency in the same amount of time, the conversion rate has to be higher.
Brew on

That's interesting about the lauter efficiency. Was this with a fly sparge or a good thorough batch sparge?