Five Gallon Fly Sparge Question?

[Gytaryst]

I batch sparged since I started brewing until I could finally set up a gravity fed system to fly sparge. From everything I've read continuous sparging gives you a better rinse and better efficiency. Also, according to what I read, the goal is to set the flow rate from the HLT to match the flow rate into the BK, and the whole process should last 45 min to an hour. I suppose on paper it sounded good.

For a 5 gallon batch I started with 10 gallons of water. BeerSmith calculated it at 9.52 gallons but I always start with more. I started out with 5 gallons of strike water, added the grain and mashed for 60 minutes. I then drained the first runnings and prepared to start sparging. It didn't go the way I saw it in my head. So when all was said and done I did some calculating.

I mashed with 5 gallons so that left me 5 gallons to sparge with. 5 gallons is 640 ounces, so to make the sparge last the required 60 minutes, thats roughly 1 ounce per minute. Put another way - it's estimated that there are 591 drops of water in a fluid ounce, so to fly sparge for an hour with 5 gallons is approximately 10 drops per second.

I drained the first runnings, so when I started the sparge I wanted to wait until the water was an inch or so above the grain bed, (as everyone suggests). I had the valve open to what I figured was a drizzle. By the time the water was a little over an inch above the grain bed - the 5 gallons in the HLT was drained.

So it wasn't really a fly sparge, it was more of a long drawn out batch sparge.

Just wondering what I'm missing.

 

[doug293cz]

You're not supposed to completely drain the MLT prior to starting the fly sparge. Just drain until the wort is 1" - 2" above the top of the grain bed, then start the simultaneous run-off and sparge water feed. Try to keep the 1" - 2" of water on top of the grain bed throughout the sparge

Brew on

 

[Gytaryst]

You're not supposed to completely drain the MLT prior to starting the fly sparge. Just drain until the wort is 1" - 2" above the top of the grain bed, then start the simultaneous run-off and sparge water feed. Try to keep the 1" - 2" of water on top of the grain bed throughout the sparge

Brew on

Possibly. I was discussing efficiency on another thread where guys kept talking about taking a gravity reading of first runnings. I mentioned that I was going to start fly sparging and one guy posted that I should still drain the MLT prior to sparging whether it's batch sparging or continuous sparging. In my non-scientific head, if the purpose of sparging is to rinse sugars out of the grain it makes sense to drain the wort first. It's probably a lousy analogy, but when you're washing dishes or clothes or whatever you don't add the rinse water to the soapy water.

But I digress. My point was that even if you don't completely drain the MLT first, you still have 5 gallons of water to sparge with. If you set the flow rate so it takes an hour to go thru 5 gallons - it's the same flow rate whether the MLT is already full or if you drain it first.

I see all these fancy sparge arms people build, especially the ones that use the water pressure to spin around like a lawn sprinkler. To set the flow rate at 1 ounce per minute so the 5 gallons takes an hour to work down thru the grain bed, 1 oz per minute is barely more than a leaky faucet? Think how slow you'd have to pour in order to take 60 seconds filling a shot glass?

And I don't mean to be anal about the 1 hour. I know there's no set in stone time. My point was that everyone mentions that for a fly sparge to be effective it should take 45 minutes to an hour. That made sense to me until it came time to actually do it and I realized how slow you'd have to set the drip to make 5 gallons last that long.

I'll try it a few more times to see what happens. Maybe for 10 gallon batches or larger it's more effective.

 

[doug293cz]

Possibly. I was discussing efficiency on another thread where guys kept talking about taking a gravity reading of first runnings. I mentioned that I was going to start fly sparging and one guy posted that I should still drain the MLT prior to sparging whether it's batch sparging or continuous sparging. In my non-scientific head, if the purpose of sparging is to rinse sugars out of the grain it makes sense to drain the wort first. It's probably a lousy analogy, but when you're washing dishes or clothes or whatever you don't add the rinse water to the soapy water.

But I digress. My point was that even if you don't completely drain the MLT first, you still have 5 gallons of water to sparge with. If you set the flow rate so it takes an hour to go thru 5 gallons - it's the same flow rate whether the MLT is already full or if you drain it first.

I see all these fancy sparge arms people build, especially the ones that use the water pressure to spin around like a lawn sprinkler. To set the flow rate at 1 ounce per minute so the 5 gallons takes an hour to work down thru the grain bed, 1 oz per minute is barely more than a leaky faucet? Think how slow you'd have to pour in order to take 60 seconds filling a shot glass?

And I don't mean to be anal about the 1 hour. I know there's no set in stone time. My point was that everyone mentions that for a fly sparge to be effective it should take 45 minutes to an hour. That made sense to me until it came time to actually do it and I realized how slow you'd have to set the drip to make 5 gallons last that long.

I'll try it a few more times to see what happens. Maybe for 10 gallon batches or larger it's more effective.

Yeah, I saw that other post. Poster was wrong. It happens. To sample the first runnings SG, you don't have to completely drain the MLT. Just vorlauf, start the run-off and grab a sample.

Fly sparging is pretty complex from a dynamics standpoint. The lighter sparge water above the heavier, more concentrated wort acts as kind of a piston to push the wort out of the grain bed, and rinses continually as it moves along. It's kind of like an infinite number of infinitesimally small batch sparges, following one after another. Rinsing math says that for a given amount of rinse water, the more rinse steps you spread the water across, the better the rinsing.

In order for the water "piston" to work correctly, there can't be and "short circuit" paths (channels) thru the grain bed that allow the sparge water to bypass most of the grain. Channeling will kill your efficiency (often to the point where it's worse than a batch sparge.) This is the main reason for using a slow rate. Another reason to go slow, is you have to allow time for diffusion of sugar out of the concentrated wort trapped in the grits, and into the sparge water.

Normally you would collect 6.5 - 7.0 gal pre-boil volume for a 5 gal batch. So that's about 840 to 900 fl oz. At 60 min/hr that works out to 14 - 15 fl oz/min sparge rate, or a little less than a pint a minute. I've seen recommendations to keep the sparge rate under 1 qt/min, which would result in about a 30 min sparge for a 5 gal batch.

You need to find out how fast you can do a sparge in your equipment, while still avoiding channeling

Brew on

 

[beermanpete]

Dave Miller has some interesting information on his site: Brew Like A Pro that will help shed some light on the subject: http://brewlikeapro.net/lautering.html

You don't mention mash-out or lautering. I know a formal mash-out has been questioned on this site but I still do it and then lauter for about 20 minutes to clear the wort and set the filter bed before begining the sparge.

You can likely run the wort out faster that 1 ounce per minute with good results. I am using a flow rate of about 1 quart per minute in a Rubbermaid 5 gallon round drink cooler (about 9.5" ID) with a Bazooka style screen with good results. My mash/lauter efficiency is typically about 80%.

 

[doug293cz]

Dave Miller has some interesting information on his site: Brew Like A Pro that will help shed some light on the subject: http://brewlikeapro.net/lautering.html

You don't mention mash-out or lautering. I know a formal mash-out has been questioned on this site but I still do it and then lauter for about 20 minutes to clear the wort and set the filter bed before begining the sparge.

You can likely run the wort out faster that 1 ounce per minute with good results. I am using a flow rate of about 1 quart per minute in a Rubbermaid 5 gallon round drink cooler (about 9.5" ID) with a Bazooka style screen with good results. My mash/lauter efficiency is typically about 80%.

Haven't looked at the linked article in a while. Lots of good information, but pretty intimidating for a beginner.

Lautering is defined as the process of separating wort from the spent grain, so the thread so far has been all about lautering. Perhaps you are confusing lautering with vorlaufing (which was mentioned) which is recirculating the wort thru the grain bed, prior to lautering, to set the grain bed and get particulate free lautered wort.

Mash out is a process that occurs prior to lautering, and has nothing to do with OP's issue, which is an incomplete understanding of the basic fly sparging technique.

80% mash efficiency is so-so when doing a fly sparge. 80% is readily achievable with no-sparge (I know because I do it regularly.) A single batch sparge can easily achieve 85%. A really well conducted fly sparge should get you into the 90's. All the previous figures are for normal size beers with a grain weight to pre-boil volume ratio of about 1.75 (about 12 lbs of grain for a 6.75 gal pre-boil volume.)

Brew on

 

[EarthwormJim]

But I digress. My point was that even if you don't completely drain the MLT first, you still have 5 gallons of water to sparge with. If you set the flow rate so it takes an hour to go thru 5 gallons - it's the same flow rate whether the MLT is already full or if you drain it first.

I think this is where the disconnect is. Even though you are going to use 5 gallons to sparge, you need to collect your full boil volume, over 9 gallons, so you need to set the flow rate to go though more than 9 gallons in an hour, not 5.

 

[helibrewer]

I batch sparged since I started brewing until I could finally set up a gravity fed system to fly sparge. From everything I've read continuous sparging gives you a better rinse and better efficiency. Also, according to what I read, the goal is to set the flow rate from the HLT to match the flow rate into the BK, and the whole process should last 45 min to an hour. I suppose on paper it sounded good.

For a 5 gallon batch I started with 10 gallons of water. BeerSmith calculated it at 9.52 gallons but I always start with more. I started out with 5 gallons of strike water, added the grain and mashed for 60 minutes. I then drained the first runnings and prepared to start sparging. It didn't go the way I saw it in my head. So when all was said and done I did some calculating.

I mashed with 5 gallons so that left me 5 gallons to sparge with. 5 gallons is 640 ounces, so to make the sparge last the required 60 minutes, thats roughly 1 ounce per minute. Put another way - it's estimated that there are 591 drops of water in a fluid ounce, so to fly sparge for an hour with 5 gallons is approximately 10 drops per second.

I drained the first runnings, so when I started the sparge I wanted to wait until the water was an inch or so above the grain bed, (as everyone suggests). I had the valve open to what I figured was a drizzle. By the time the water was a little over an inch above the grain bed - the 5 gallons in the HLT was drained.

So it wasn't really a fly sparge, it was more of a long drawn out batch sparge.

Just wondering what I'm missing.

You mashed 5 gallons for a 5 gallon batch size?? Your mash should have been something much closer to 3 gallons.

For continuous sparging, you don't runoff the MT completely first. You slowly start draining the MT into the kettle (or a grant) at about 1L per minute and start adding sparge water to the MT when the liquid level is about one in from the top of the grain bed.

At this point you want to match the outflow and incoming sparge water flow to try to maintain the 1" water level above the grain bed.

When your sparge water is exhausted, you just continue to drain your MT until 1) you reach your pre-boil volume, or 2) the MT is completely drained, whichever happens first. Then either top-up the kettle or accept the volume that you have....take a gravity reading and see if topping-up makes sense or if it will over-dilute your wort.

 

[Gytaryst]

Good advice. I'm going to try it without draining the MLT next time. I vorlaufed for about 10 minutes and didn't notice the wort getting much clearer. I was brewing a stout so I wasn't too worried. I abandoned all the clarifying hoops I usually jump thru. I have more important issues to deal with right now than whether I can read a newspaper thru my beer or not. I haven't read a newspaper in 30 years and I can honestly say I've NEVER read one thru a beer.


I was vorlaufing with only one pitcher so I had to keep opening and closing the ball valve. I don't know if that matters or not but it seems like it would be better to have two pitchers and just keep the valve opened to a constant trickle. I always go into a brew thinking I'm going to really focus on doing an effective vorlauf, but after 5 or 10 minutes with no noticeable change that I can see, I usually just abandon that part and move on to the next step.

 

[MaryB]

I only use 1 pitcher to sparge, never had an issue with opening and closing the valve.

 

[kh54s10]

When I vorlauf, I don't worry about crystal clear. I am not sure that happens anyway. I have a clear pitcher and I slowly draw off wort. At the beginning I can see "rapids" in the flow down the side of the pitcher caused by grain particles. It starts out like chocolate milk. After a while it looks translucent but I have never gotten clear. This takes a little more than a quart drawn off into my 2 quart pitcher. I never close the valve then open for more vorlauf.

 

[Gytaryst]

I only use 1 pitcher to sparge, never had an issue with opening and closing the valve.

... I never close the valve then open for more vorlauf.

I guess it's like everything else regarding home brewing. You can ask questions, but in the end you just have to reinvent the wheel and figure things out for yourself.

Some vorlauf for 15 minutes, some vorlauf for 15 seconds. I've tried a bunch of different ways and so far I've never really noticed that it made much of a difference one way or the other. I have absolutely no doubt that I'm missing something or else just have a wrong concept about what I'm actually trying to achieve by vorlaufing?

I never expected to get crystal clear wort, and that was never my objective. What I was saying is that I've never noticed much difference in the wort - no matter how long I spent doing it. If I pulled off 3 pitchers, the wort going into the third pitcher looked like the wort going into the first pitcher. If I pulled off 10 pitchers, the wort going into the tenth pitcher looked like the first. That was really my only point there. Not that I expected jewel clear wort - just that I kind of expected some difference.

I'm going to try it using two different pitchers so I can keep the valve open continuously. I was using a piece of aluminum foil floating to pour it back in without disturbing the grain bed. Then I read other's on here who said as long as there's an inch or two of liquid above the grain bed and you pour gently, it's not going to disturb the grain bed - so I tried that. No matter how gently I poured, I kicked up some grain, so I'm not sure if that was good advice.

I'll try two pitchers, floating the aluminum foil, and vorlauf for at least 15 minutes or longer with a continuous trickle flow rate. Then start fly sparging without draining. If I can't see any noticeable difference after that, maybe I'll try BIAB. I don't know.

What I do know is that it's getting pretty frustrating. I know it's just because I'm missing something simple, or not completely understanding the objective in certain things. I'm excited about every brew, thinking I finally got some of the major issues worked out. And after every brew I'm scratching my head thinking, "I thought I had that worked out - guess not."

 

[kh54s10]

What I look for when doing my vorlauf is to get no grain husk particles. It starts off milky then goes translucent. I rarely need more than a quart before there are no particles and it goes translucent. I also don't worry about some grain disturbance when returning the wort. The grainbed is set to act as a filter. As long as pouring the wort back does not dig in several inches, there is no concern. I use a water heater braid in my mash tun. (Batch sparging) I just pour the wort back in by pouring it down the side of the mash tun, slowly. I don't think there needs to be a difference in vorlauf technique for fly or batch sparging. Just do it enough until the wort has no debris in it.

You don't want to be boiling chunks of grain. This might extract tannins making your beer harsh.

Other than that, I think you are over analyzing this. Try drawing off just one pitcher. If you don't see grain particles in the wort the vorlauf has worked.

 

[beermanpete]

I had the opportunity to participate in a brew event at Smog City in Torrance, CA adn watched the entire brew cycle and was allowed to talk with the brewer and asked a lot of questions and such. They vorlauf until the wort is clear as viewed through a sight glass in the lines. This took over 30 minutes as I recall.

I usually vorlauf for at least 15 minutes and can see some improvement but I get impatient and move on before it is totally clear. By the end of the sparge cycle the run-off is crystal clear but it is mostly water by that point, of course.

 

[kh54s10]

I had the opportunity to participate in a brew event at Smog City in Torrance, CA adn watched the entire brew cycle and was allowed to talk with the brewer and asked a lot of questions and such. They vorlauf until the wort is clear as viewed through a sight glass in the lines. This took over 30 minutes as I recall.

I usually vorlauf for at least 15 minutes and can see some improvement but I get impatient and move on before it is totally clear. By the end of the sparge cycle the run-off is crystal clear but it is mostly water by that point, of course.

I think the 30 minute comparison is invalid.. How many barrels is their batch? I doubt they would vorlauf a 5 gallon batch for 30 minutes unless it is just because that was the way they learned.

Again, I have never drawn off more than 2 quarts and I would stack up my average beer with any average commercial brew. My friends always have good things to say about my beers so it is not just me. And this is not just to me, but to their friends.

 

[doug293cz]

...

You don't want to be boiling chunks of grain. This might extract tannins making your beer harsh.

...

If boiling grains extracted tannins, then no one would do decoction mashes, where large amounts of grains are boiled. You won't extract tannins unless your wort pH is ~6.0 or higher. Your wort should have a pH of 5.6 or less.

You actually don't need to vorlauf at all. Any particulates that make it thru to the boil will eventually settle out in the fermenter. A lot of BIAB'ers (including me) start out with very turbid wort, but end up with crystal clear beer (cold crashing and fining do help a lot.)

Vorlaufing does have the benefit of moving any low SG wort from under a false bottom (unless you recirculate your mash, the only way sugar gets into the wort under the FB is by diffusion) to the top of the mash, which can provide a slight boost in lauter efficiency.

Brew on

 

[kh54s10]

If boiling grains extracted tannins, then no one would do decoction mashes, where large amounts of grains are boiled. You won't extract tannins unless your wort pH is ~6.0 or higher. Your wort should have a pH of 5.6 or less.

You actually don't need to vorlauf at all. Any particulates that make it thru to the boil will eventually settle out in the fermenter. A lot of BIAB'ers (including me) start out with very turbid wort, but end up with crystal clear beer (cold crashing and fining do help a lot.)

Vorlaufing does have the benefit of moving any low SG wort from under a false bottom (unless you recirculate your mash, the only way sugar gets into the wort under the FB is by diffusion) to the top of the mash, which can provide a slight boost in lauter efficiency.

Brew on

I agree that extracting tannins is not likely a problem, but that is why most people take care in doing a vorlauf.

I am not sure that boiling grain particles and doing a decoction are really the same thing, in the latter you are returning the boiled portion to the mash. In the former you are not. But I am no chemist, and have never made the experiments needed.

As I stated earlier I think people take these things far to the extreme.

 

[beermanpete]

I think the 30 minute comparison is invalid.. How many barrels is their batch? I doubt they would vorlauf a 5 gallon batch for 30 minutes unless it is just because that was the way they learned.

Again, I have never drawn off more than 2 quarts and I would stack up my average beer with any average commercial brew. My friends always have good things to say about my beers so it is not just me. And this is not just to me, but to their friends.

The system at Smog City is 16 barrels as I recall. As you point out, the time may for the wort to clear may be different but this is likely true of any two system of different design even if the volume is the same. I think what is worth noting is the fact that they have the ability to view the wort while it is in motion and they vorlauf until it runs clear rather than moving on to lautering at a fixed time.

 

[kh54s10]

The system at Smog City is 16 barrels as I recall. As you point out, the time may for the wort to clear may be different but this is likely true of any two system of different design even if the volume is the same. I think what is worth noting is the fact that they have the ability to view the wort while it is in motion and they vorlauf until it runs clear rather than moving on to lautering at a fixed time.

Read my replies.. I do this. I have a clear 2 qt pitcher. I run the wort down the side. I can see "rapids" of the wort going over debris. When that stops a couple cups more and it is free of debris. It starts out cloudy then goes translucent. It is always less than 2 quarts to get there.

5-10 minute at the most!!

 

[MaryB]

6-8 quarts before I stop seeing grain bits come through. But a tiny amount of grain in the boil will not make any difference in flavor.

 

[Gytaryst]

If clarity is the only reason for vorlaufing then it's not a major concern for me. I throw a whirfloc tab in the boil. If I want the beer clearer I cold crash for 2 or 3 days before bottling, and if I want to go extreme I add gelatin. I can't say I've ever had crystal clear beer, but it's plenty clear enough. Perfectly clear see-thru beer has never been high on my list of priorities to focus on.

My MLT is a bottom drain keggle with a Brew Bag sitting on a 10" round grate, so there's not very much liquid sitting below the grain bed to begin with.

I posted another thread about wanting to raise my efficiency and got a lot of responses from people who get 75% to 80% efficiency telling me how efficiency isn't that important. So I've kind of avoided the fact that everything I'm doing regarding my mashing techniques is specifically being done to increase my efficiency. I believe my mash efficiency is OK, so as far as I can tell my low efficiency is probably due to issues with lautering. I'm just trying to understand that process better... while at the same time trying to avoid that whole "consistency is more important than efficiency" discussion again.


Cheers

 

[helibrewer]

The keys to mash efficiency are; 1) crush, 2) pH (5.2-5.3), 3) temp, liquor:grist, 4) Ca > 50ppm (helps with beta-amylase). Mash efficiency maximizes extraction, limited by your equipment.

Lautering efficiency is separate from mash efficiency with crush being the most related parameter since it has the greatest impact on run-off. Lautering efficiency maximizes the recovery of the extract, again limited by your equipment.

Every brewhouse varies because equipment and process impact both of these efficiencies.

 

[doug293cz]

The keys to mash efficiency are; 1) crush, 2) pH (5.2-5.3), 3) temp, liquor:grist, 4) Ca > 50ppm (helps with beta-amylase). Mash efficiency maximizes extraction, limited by your equipment.

Lautering efficiency is separate from mash efficiency with crush being the most related parameter since it has the greatest impact on run-off. Lautering efficiency maximizes the recovery of the extract, again limited by your equipment.

Every brewhouse varies because equipment and process impact both of these efficiencies.

What you are calling "mash efficiency" is called "conversion efficiency" by both BeerSmith and BrewersFriend, and those seem to be the two most popular sets of brewing software around here. So, to prevent confusion, caused by using the same word to mean different things, we should stick with the most common definitions. BeerSmith uses "mash efficiency" to refer to conversion efficiency times lauter efficiency. This is efficiency to the boil kettle, and BrewersFriend uses "pre-boil efficiency" where BeerSmith uses "mash efficiency."

The rigorous definitions are:
Conversion Efficiency = Weight of extract created in mash / Max potential extract weight from grain bill
Lauter Efficiency = Weight of extract collected in boil kettle / Weight of extract created in mash
Mash Efficiency = Pre-Boil Efficiency = Weight of extract collected in boil kettle / Max potential extract weight from grain bill = Conversion efficiency * Lauter efficiency
Often we use "sugar" and "extract" interchangeably, but extract, while mostly sugar, also includes proteins and other soluble matter from the mash.

Also, the pH range for getting good conversion efficiency is much wider than you state. It's more like 5.2 to 5.7. And many brewers consider 5.2 - 5.3 to be a little low as a mash pH target.

Crush has very little effect on lauter efficiency, as long as it isn't so fine that it results in a stuck lauter. Crush has it's greatest effect on conversion efficiency, where finer leads to faster conversion, which usually means higher conv efficiency.

Brew on

 

[Gytaryst]

My system is a 3 keggle gravity fed.
1) My HLT is a keggle with 1/2" dip tube and ball valve and sight glass.
2) My MLT is a bottom drain keggle with the Brew Bag
3) BK is just a keggle with 5/8" dip tube and 1/2" ball valve
4) My chiller is a 25' immersion chiller 3/8" copper placed in the BK with a ice bath and fountain pump pumping ice water thru it.

I'm using the brew bag so I can crush my grain to .025. I use the Bru N' Water spreadsheet to calculate my water profile and a digital pH meter to measure pH. I try to keep the mash pH down to 5.2 - 5.6, but in all honesty I've always taken the pH measurement after I added the strike water to the MLT, but I have never checked it after I added the grain. So I suppose I'm not really getting a "mash" pH. Rather just a strike water pH.

I keep as close an eye as I can on my mash temp. I have the keggle insulated to the hilt with reflectix and foam rubber. I was losing less than 1 degree on a 60 minute mash. (It helps that the ambient temp here in Arizona is almost the same as the mash temp)

Then someone suggested that I would get better efficiency if I stirred the mash every 15 or 20 minutes - so I lose 2 or 3 degrees now by opening the MLT to stir it. RIMS is a possibility down the road.

I "THINK" my equipment is efficient enough. It's just a matter of understanding everything I'm doing, why I'm doing it, and finding the right techniques.

My next "tweak" will be to the chiller. It takes me 30-45 minutes to get the wort down from boiling to pitching temp with the system I have. I'd like to knock that down substantially without using a plate chiller or pump. Probably a more efficient version of the system I have now.

Anyway - I'm getting there... one brew at a time.

Cheers guys

 

[helibrewer]

What you are calling "mash efficiency" is called "conversion efficiency" by both BeerSmith and BrewersFriend, and those seem to be the two most popular sets of brewing software around here. So, to prevent confusion, caused by using the same word to mean different things, we should stick with the most common definitions. BeerSmith uses "mash efficiency" to refer to conversion efficiency times lauter efficiency. This is efficiency to the boil kettle, and BrewersFriend uses "pre-boil efficiency" where BeerSmith uses "mash efficiency."

The rigorous definitions are:
Conversion Efficiency = Weight of extract created in mash / Max potential extract weight from grain bill
Lauter Efficiency = Weight of extract collected in boil kettle / Weight of extract created in mash
Mash Efficiency = Pre-Boil Efficiency = Weight of extract collected in boil kettle / Max potential extract weight from grain bill = Conversion efficiency * Lauter efficiency
Often we use "sugar" and "extract" interchangeably, but extract, while mostly sugar, also includes proteins and other soluble matter from the mash.

Also, the pH range for getting good conversion efficiency is much wider than you state. It's more like 5.2 to 5.7. And many brewers consider 5.2 - 5.3 to be a little low as a mash pH target.

Crush has very little effect on lauter efficiency, as long as it isn't so fine that it results in a stuck lauter. Crush has it's greatest effect on conversion efficiency, where finer leads to faster conversion, which usually means higher conv efficiency.

Brew on

The pH data comes from Hough, Briggs, Stevens and Young, 1982. This data was further supported by Rock Bottom when they analyzed the data across all of their breweries looking for the cause of brewhouse yield problems (degrees Plato actual*bbl actual)/(degrees Plato target*bbl target). Rock Bottom found brewhouse yield decreased by about 2% for pH's more than 0.2 out of the range I stated.

Brad's definition of mash efficiency is terrible, it doesn't even make sense intuitively.

I can live with conversion efficiency, although there are many things in the resulting extract which are not "converted".

In any case, Rock bottom also found that crush had the most significant impact. All of their breweries that used the their ideal grind spec (>70% retained on a #14 sieve), exceeded 89% brewhouse yield...none of the breweries with finer grind had >89% yield.

Another thing to consider is the liquor:grist ratio and how it impacts the relationship between extract and fermentability (extract and fermentability are inversely related)

a. Thin mash = high liquor/grist ratio, higher extract & lower fermentabilty
b. Thick mash = low liquor/grist ratio, lower extract & higher fermentabilty

 

[doug293cz]

The pH data comes from Hough, Briggs, Stevens and Young, 1982. This data was further supported by Rock Bottom when they analyzed the data across all of their breweries looking for the cause of brewhouse yield problems (degrees Plato actual*bbl actual)/(degrees Plato target*bbl target). Rock Bottom found brewhouse yield decreased by about 2% for pH's more than 0.2 out of the range I stated.

The Rock Bottom study pH range you give is for measurements at mash temp. If you visit HBT's "Brew Science" forum, you find that the recommendations are universally for room temp pH measurements, to prolong the life of the expensive pH probes. Rock Bottom's optimal pH recommendation for room temp measurements is 5.5 - 5.6. Kai Troester gives the optimal range (room temp) as 5.3 - 5.5, and acceptable range as 5.2 - 5.7. pH is just one of the variables that has an effect on conversion rate. Other variables are mash temp, crush fineness, and mash thickness.

Brad's definition of mash efficiency is terrible, it doesn't even make sense intuitively.

Agreed. But if you look at what actually is output by BeerSmith, it is "extract to BK divided by potential extract." If you carefully parse his written definition it matches, but it's not really clear.

I can live with conversion efficiency, although there are many things in the resulting extract which are not "converted".

True, but homebrewers think most about the sugar (even if they should care about the other stuff as well.) Perhaps a better term than conversion efficiency would be "solubilization" efficiency. However, that doesn't readily roll off the tongue, and I doubt it would meet with much acceptance. I'm not arguing that the consensus definitions are the best or most intuitive, just that we should stick with them to avoid any more confusion.

If I were allowed to rule the world, and pick my own terminology, I would use "mash" efficiency for amount of extract actually created in the mash divided by potential extract (i.e. the conventional definition of conversion efficiency.) "Lauter" efficiency stays as extract to BK divided by extract created in the mash. And "extract" efficiency would be extract to BK divided by potential extract (i.e. the conventional definition of mash efficiency.) These seem the most intuitive and self descriptive to me. However, I gave up trying to change the world, w.r.t things I could live with, a long time ago.

The Rock Bottom study throws in a new definition for "brewhouse" efficiency. They use it to refer to mash or pre-boil efficiency. So be aware of this if you read the linked study.

In any case, Rock bottom also found that crush had the most significant impact. All of their breweries that used the their ideal grind spec (>70% retained on a #14 sieve), exceeded 89% brewhouse yield...none of the breweries with finer grind had >89% yield.

What Rock Bottom found optimal for their 8, 12 and 15 BBL brewhouses does not necessarily translate to our 5 - 15 gal brewhouses. Their larger systems have much deeper grain beds, with much higher wort velocities during lautering, than do typical homebrew systems. This means they need a much coarser crush in order to avoid struck lauters at the flow rates they need to get productivity (i.e. less than two hour lauters.) Their conclusion that coarser crush improves efficiency applies only to lauter efficiency, not conversion efficiency. And furthermore, it is only applicable to higher volume systems.

Another thing to consider is the liquor:grist ratio and how it impacts the relationship between extract and fermentability (extract and fermentability are inversely related)

a. Thin mash = high liquor/grist ratio, higher extract & lower fermentabilty
b. Thick mash = low liquor/grist ratio, lower extract & higher fermentabilty

Kai Troester says the opposite about mash thickness vs. fermentability:

"... as a result thinner mashes are known to give more fermentable worts at normal mashing temperatures."​

One thing I found disappointing about Rock Bottom's presentation is they offer no explanation as to why (over) stirring the mash results in less grain bed permeability. This runs counter to the practice of using rakes in mash/lauter tuns in commercial systems. And, is counter intuitive in general.

Brew on

 

[Gytaryst]

... In any case, Rock bottom also found that crush had the most significant impact. All of their breweries that used the their ideal grind spec (>70% retained on a #14 sieve), exceeded 89% brewhouse yield...none of the breweries with finer grind had >89% yield.

???
That's one of those statements that seems to be completely contrary to what I've been told, or common sense for that matter. How can a finer grind possibly produce a lower efficiency?

I'm not doubting that it's true - it just strikes me as odd.

 

[doug293cz]

???
That's one of those statements that seems to be completely contrary to what I've been told, or common sense for that matter. How can a finer grind possibly produce a lower efficiency?

I'm not doubting that it's true - it just strikes me as odd.

In a large MLT, with a deep grain bed, finer grind causes more flow resistance, leading to higher pressure drop thru the grain bed, which ends up compacting the bed, adding more flow resistance, leading to slow/stuck lauters. Finer grind increases conversion efficiency (by increasing gelatinization rate, and sometimes allowing more gelatinization.) Coarser grind improves flow during lautering, which can improve lauter efficiency on in deep MLT's. Since mash efficiency = conv eff * lauter eff, you want to find how to optimize each on your equipment. Rock Bottom found out how to optimize their equipment. Your equipment is different than Rock Bottom's, so don't take their advice as gospel.

Brew on

 

[Gytaryst]

In a large MLT, with a deep grain bed, finer grind causes more flow resistance, leading to higher pressure drop thru the grain bed, which ends up compacting the bed, adding more flow resistance, leading to slow/stuck lauters. Finer grind increases conversion efficiency (by increasing gelatinization rate, and sometimes allowing more gelatinization.) Coarser grind improves flow during lautering, which can improve lauter efficiency on in deep MLT's. Since mash efficiency = conv eff * lauter eff, you want to find how to optimize each on your equipment. Rock Bottom found out how to optimize their equipment. Your equipment is different than Rock Bottom's, so don't take their advice as gospel.

Brew on

AH! That makes sense. I'm starting with the finest setting I can get on my grain mill, (.025). The issue I had last time was sparging too fast - not too slow. I think I'll keep the grind where it's at for a few more brews and play around with the sparging.

Not that I think 12 pounds of grain in a keggle is even remotely close to what a commercial brewer has to deal with.

 

[helibrewer]

As for the mash stirring bit, we discussed that in class and the consensus was that not stirring makes sense in a single vessel MLT. Rakes aren't used in combination vessels, just in dedicated lauter tuns which are very wide and shallow....same with mash mixers, they are only used in dedicated mash tuns.

 

[helibrewer]

With regard to the thin/thick mash item. Thin mashes have lower fermentability because beta-amylase is a limiting enzyme. There is adequate alpha-amylase in a wide range of dilutions, but beta-amylase activity decreases with even moderate dilutions and since beta-amylase accounts for about a 70% contribution to fermentability, the fermentability decreases as the mash is diluted. Lewis and Young Brewing, 2nd addition address it. A vast majority of professional brewers use a L:G of about 3. That equates to homebrewers as 1.42 qts/lb of grain.

 

[Gytaryst]

As for the mash stirring bit, we discussed that in class and the consensus was that not stirring makes sense in a single vessel MLT. Rakes aren't used in combination vessels, just in dedicated lauter tuns which are very wide and shallow....same with mash mixers, they are only used in dedicated mash tuns.

I never stirred the mash. For single infusion I got my rest temp stabilized and then just let it go 45 min to an hour, (or more - depending). In another thread I was asking about ways to increase efficiency and a couple of guys suggested stirring the mash every 15 to 20 minutes. I tried that the last time I brewed and didn't have any increase in efficiency. What I did note was that my mash temp dropped a lot more due to opening the MLT to stir. I can't directly heat my MLT nor do I have the capability to recirculate. If I don't open the MLT I only lose 3/4 of a degree in 60 minutes. Opening it caused it to drop, plus stirring it cooled it down even more, so I had to add 1.5 qts of boiling water to bring it back up to rest temp. Not the end of the world I suppose - I just thought it caused more problems and more work than it was worth. If I would have seen a significant jump in my efficiency then I probably would have worked that into my routine. As it is I think I'll go back to stirring real good when I dough in and then not worry about it.

 

[MaryB]

I might stir once during winter when temps in the garage are 40 or so. Mash in at 1.5 quarts per pound. Average brew house efficiency is 80%. And that is with a traditional stainless mash kettle(11 gallon batches). If I add an insulated jacket in winter I can probably skip the stirring.

 

[Gytaryst]

I might stir once during winter when temps in the garage are 40 or so. Mash in at 1.5 quarts per pound. Average brew house efficiency is 80%. And that is with a traditional stainless mash kettle(11 gallon batches). If I add an insulated jacket in winter I can probably skip the stirring.

I tried stirring every 20 minutes last weekend. I'm not going to do that anymore. Extra work, extra hassle, and I didn't notice any difference in efficiency. As far as I can tell the only thing I accomplished was causing a bigger drop in mash temp than necessary.