Fly sparge: drain or maintain

[DraconianHand]

I am new to fly sparging having recently stepped up to a HERMS system with a float control from a 5 gallon Igloo batch sparge system.

The last 5 brews I have continued to add sparge water during the sparge until I had reached my preboil volume. Right now my efficiency is about 65% (I have a mill on order so I can make some adjustments).

I realized that at the end of my 60 minute sparge, I have about 4.5 gallons (dependant on grist weight @ 1.5 q/lb) of low gravity wort sitting in the MLT. Say about 40 gravity points.

My question is this:

Should I continue to add sparge water during the entire sparge as I do now, which leaves wort behind in the MLT.

Or should I stop adding sparge water at some point and let the MLT drain into the kettle, taking the sugars out?

It seems that most people on HBT go with the former, but I have seen others go with the latter. Additionally, most of the books, articles and websites that speak to calculating the volume of water required for brewing, calculate the water required to get you to post boil volumes. This means no additional sparge water and that you are draining the MLT at the end of the sparge.

 

[Lil' Sparky]

When I fly sparged (much prefer batch BTW) I calculated how much sparge water and then let the MLT drain at the end. It made more sense to me that way, but my guess is there's not much difference.

 

[Bombo80]

I used to only fly sparge, my AG brews. I always used a 1.33qt/lb grist ratio, and about 1.5qt/lb for my sparge water. I usually ended up with about 5 gallons of sparge water, with a preboil volume ranging from 6 to 8 gallons. My fly sparging sessions usually took around an hour, considering the runnings being drawn off at 1 qt per minute, and that included the recirculation of the initial runnings, to clear them up.

I have a commercial coffee grinder for crushing my grains. It's like a huge motorized version of the Corona grain mill. It has a stationary plate, and a spinning plate, and has a handle that I can adjust the plate spacing as I am crushing the grains. I have checked the gap with a feeler gauge, and marked this on the chassis, so I know where my .045" is at. I was always right around the 70% mark, for efficiency. I always just filled my boil pot with what came out of the lauter tun, after all the sparge water had been added. I kept the spout open, and added the running until the wort hit the hot break. By that time the runnings were usually pretty light.

So if you have calculated the proper amount of mash water, and sparge water, you shouldn't have to add any more water for your preboil volume. I have done several brews that were around the 1.080 mark, following this method. I have just recently converted a cooler to a MLT, and did my first batch sparge. I think it will work well, once I can get my copper manifold to stay together.

Good luck

 

[Boerderij_Kabouter]

I am a fly sparger and I continually wash the grains until I have my pre-boil volume. Then I close by valve and thats that, I leave the remaining wort in the mash tun. Normally my runnings are not 1.040 though. That must have been a big beer to be running 1.040 after an hour sparge!

The way I look at this is, when I am in the shower and rinsing myself off, the best way is to stand under the water and let it continually rinse all the soap off of me. I would not get very wet, then stop the water and allow all the soapy water to drip off of me.... I don't know if that made sense, but it does in my head.

Basically, I think you get a better rinsing of the grains by continually passing water through the grain bed and stopping when you have reached the desired volume, our your runnings are dropping below the desired gravity (no lower than 1.008 for tannins).

I would be interested to hear others takes on this.

 

[jdoiv]

I fly sparge and will figure that I need 1/2 gallon per pound of grain for average beers. I'll usually stop adding water in around the 40 minute mark as I'll have a good 4 to 6 inches of water on top of the grain bed by then. Then slowly drain the MLT until I've reached my pre-boil volume. I may end up with a little wort left in the MLT, but usually not much. I usually get around 87% efficiency this way.

 

[JoePolvino]

I fly sparge and regularly get around 85-88%. What I do is fly sparge until I get about half my pre-boil volume, then shut down the tun output and then add another gallon or so of water to the tun. Then I stir the mash well, vorlauf, and then resume sparging into the boil pot. When I'm about 1.5 gallons shy of my target volume, I stop the HLT water and slowly pump the remainder into the boil pot.

My guess is that this practice loosens sugars that may get trapped as water presses down on the grain and finds the path of least resistance to the manifold.

 

[DraconianHand]

Normally my runnings are not 1.040 though. That must have been a big beer to be running 1.040 after an hour sparge!

I think you misunderstand a bit.

It is 40 gravity points for 4.5 gallons, which is around 1.008 to 1.010 a gallon.

 

[Bobby_M]

Think of fly sparging this way. Imagine a 1/4" high plane of water the same width and length of your MLT progressively falling through the grainbed. For every inch it falls, it takes in a little more sugar. If your equipment is working properly, that plane of sparge water will be as saturated as it's going to get by the time it reaches the bottom of the tun. In order to maximize your efficiency, you could technically continue to sparge until the runoff reaches 1.010. In many cases though, you're going to well exceed a manageable preboil volume before that happens. It shouldn't matter how much water still left in the tun.

If you can't get 80% efficiency by fly sparging, there's got to be something fundamentally wrong though. You might as well batch sparge.

 

[Bobby_M]

I fly sparge and regularly get around 85-88%. What I do is fly sparge until I get about half my pre-boil volume, then shut down the tun output and then add another gallon or so of water to the tun. Then I stir the mash well, vorlauf, and then resume sparging into the boil pot. When I'm about 1.5 gallons shy of my target volume, I stop the HLT water and slowly pump the remainder into the boil pot.

My guess is that this practice loosens sugars that may get trapped as water presses down on the grain and finds the path of least resistance to the manifold.

Huh? This is like an intentionally slowed version of a batch sparge. Why not just go with a full on batch sparge if you're going to stir water into the mash?

 

[DraconianHand]

Hypothetically, lets say that:

• I need 9 gallons of 1.040 wort at preboil (360 gravity points)
• I continue to sparge until I reach the 9 gallons
• At the time I reach 9 gallons, my runoff is 1.010
• With a 12 lb. grist (@ 1.5 qt/lb) I have 4.5 gallons of wort in the MLT at the end of the sparge. (45 gravity points)
• 45 gravity points is 12% of the 360 gravity points in the kettle

So I could add several percentage points of efficiency by draining the MLT instead of sparging until I reach preboil volume.

I am not trying to be exact, just ballparking to provide a rough example.

 

[JoePolvino]

Huh? This is like an intentionally slowed version of a batch sparge. Why not just go with a full on batch sparge if you're going to stir water into the mash?

I certainly could, since my rig easily supports both fly and batch sparging, but I'd have to modify my manifold to a stainless braid to batch sparge. Plus I enjoy the simplicity of just balancing the in and out water flow with fly sparging.

Also, I'm not convinced a full-on batch sparge would extract as much sugar as my method.

 

[Bobby_M]

Drac,
You're thinking too much like a batch sparger IMHO. If you measured that last running at 1.010, you can't assume that the remaining liquid in the MLT is also 1.010. In fact, if you're doing it right, the very top will be 1.00000 and the middle will be somewhere near 1.005.

One other note, just because you intially strike with 4.5 gallons doesn't mean it remains availabe after the mash. Don't forget about grain absorbtion. So, in your hypothetical example, you more likely have about 2 gallons available with the top portion at 1.000 and the bottom at 1.010. It would average out to about 10 gravity points overall.

 

[FSR402]

I certainly could, since my rig easily supports both fly and batch sparging, but I'd have to modify my manifold to a stainless braid to batch sparge. Plus I enjoy the simplicity of just balancing the in and out water flow with fly sparging.

Also, I'm not convinced a full-on batch sparge would extract as much sugar as my method.

Why would you have to change anything? You are kind of batch sparging now with just a really slow drain and fill.

 

[JoePolvino]

Yeah, I guess I never thought of it that way!

To me, batch sparging is: fill, stir, recirc, drain, repeat.

My process is: fill, stir, recirc, fly sparge for a while, repeat fill+stir+recirc, fly sparge some more.

 

[Boerderij_Kabouter]

Well put Bobby. Man my shower example was weak...

 

[Bobby_M]

One of the benefit of a well excecuted fly sparge is absolute maximum efficiency at the cost of time.

The benefit of batch sparging is time savings at the cost of some arguable amount of reduced efficiency (mostly dependent on target OG and process).

Trying to combine the two seems counterintuitive to me. The concepts are mutually exclusive. Fly sparging is a progressive rinsing while batch is a full saturation then drain. I don't believe you get the best of both worlds when you combine them.

 

[DraconianHand]

You're thinking too much like a batch sparger IMHO. If you measured that last running at 1.010, you can't assume that the remaining liquid in the MLT is also 1.010. In fact, if you're doing it right, the very top will be 1.00000 and the middle will be somewhere near 1.005.

Guilty. This fact did actually cross my mind, as did a lot of other ideas. I figured, correctly, that if my thinking was indeed flawed then someone would point it out.

One other note, just because you intially strike with 4.5 gallons doesn't mean it remains availabe after the mash. Don't forget about grain absorbtion. So, in your hypothetical example, you more likely have about 2 gallons available with the top portion at 1.000 and the bottom at 1.010. It would average out to about 10 gravity points overall.

Actually, in my system the volume in the MLT stays pretty much constant. With a 12 lb. grist @ 1.5 q/lb (I prefer it a bit more fluid since I use a pump), I put 18q or 4.5 gallons of strike water in. The grist absorbs about .25q of water per pound or just over a gallon. Prior to starting the sparge, I position my float switch approximately 1 inch above the top of the mash. This 1+ inch (including float travel) gives me back the water absorbed by the grain. The float, in conjunction with my pump, keeps the sparge water at the same level. So, although the volume of the mash may have increased from mash to sparge, the volume of water is pretty much the same at sparge as at strike.

I am getting 65% efficiency, which is ok since it is consistent, but I guess I would like to get a bit more. My grain crush hasn't changed from when I was batch sparging. My mash is 30 minutes longer than when I batch sparged and my sparge is about 60 minutes (5 gallons). Mash temps vary based on recipe, but not so much from batch to batch.

 

[jdoiv]

What is your MLT? Do you use a braid, manifold or false bottom? That isn't a very good efficiency for fly sparging. There could be a number of things impacting that number, but I would start by looking at your MLT design first.

Braids are good for batch sparges but not so good for fly. Manifolds work a good bit better but aren't ideal. False bottoms are the best for a fly sparge. If you are limited by the equipment, perhaps changing procedure would help.

After equipment, I would look at pH and water chemistry if your thermometers are accurate.

 

[DraconianHand]

I have a SS MLT with a false bottom. To be more precise, I have a B3-1550.

Water PH shouldn't be a problem as it wasn't a problem when I was batch sparging (75% eff). Does PH play a bigger role in fly sparging vs. batch sparging? I don't remember reading anything that indicated this. The only change in my water is that I now run it through a carbon filter, whereas when I was batch sparging it was straight tap.

As for temp guages, the MLT has two. One analog and one digital. Both read the same, but I have not verified that the temperature they both read is correct. I guess I just figured, perhap erroneously, that the chances were slim that they we both off to the same degree.

 

[DraconianHand]

One more thing.

After the mash is complete, but before vorlauf/recirc, should I stir the mash.

Right now, I don't disturb the mash before I begin sparging. My HERMS recirculates during the mash to keep the temp constant.

 

[jdoiv]

Ok, I have the 1500 which is similar. I don't use the HERMS very often though and don't have the digital smart.

Here's my process though. I mash with 1.25 qts/lb not counting what is below the false bottom. Add my 5.2 buffer and any water salts for the style. I'll dough in in 2 or 3 additions stirring between until all the grain is in the MLT. Hold the temp (150-156) for an hour. Stir mash every 15 minutes or so. If I lose some temp, I'll gently add heat and stir. Start recirc and heat to mash out while stirring the mash. Start the sparge and collect run off for one hour at least. I'll stop adding sparge water when it's about 40-45 minutes through the sparge and drain the MLT of almost all the liquid.

I routinely get 85-92% efficiency doing this.

pH can be a factor in the sparge as it will lead to tannin extraction, but shouldn't effect efficiency. pH will effect the efficiency of the mash. As long as the mash pH is within range, you should be good. You will need to keep an eye on it during the sparge though to protect against tannin extraction.

I think you need to take a look at the following things.
One, water pH and the pH of your Mash (use the 5.2 and you won't need to worry much about this). Once you have a strong handle on the process, you can go back to water chemistry and cut back or eliminate the 5.2.

Two, grain crush. Crush till you are scared. If you don't have a mill, buy one. If you do, use feeler gauges and adjust to a finer crush.

Three, check the therms. Chances are they set the analog one to what the digital one said. If the digital was off, then they both are. Get a traceable one from professional equipment or a lab therm and check them.

Four, stir your mash more and make sure the grain bed isn't compacting from the suction of the pump during the HERMS. I think this could be a big problem for you as it will lead to channeling and really bad efficiency. Definitely stir the mash after your done with the herms and before you vorlauf.

If that doesn't get you a mid to high 80's efficiency, something else is wrong. That system should give you awesome efficiencies every time.

 

[Bobby_M]

I hope you get it figured out because I like when fly spargers are able to make a really good case for the longer process by quoting 95% efficiency. At 65%, it doesn't make the batch vs. fly debate fun anymore.

I think the grain bed compaction idea is right on. You can easily test it by stirring the mash like crazy, then a gentle vorlauf (not pump driven) prior to the sparge.

Also, are you getting the grainbed up to 168ish prior to sparging and using 170F sparge water?

 

[DraconianHand]

I have the 1550 with DigSmart and HL.

I mash with 1.5 q/lb as the pump runs when the heat in the MLT drops below the set point. I don't touch the mash for 45 minutes, but some recirc does occur. At the end of the mash, I bring the mash temp to 168*F by recircing through the HLT. When it is time to sparge, I set my float to maintain 1" or so of water above the mash and sparge for about 60 minutes. The sparge continues until I get my preboil volume or 1.008 (never gotten this low though, 1.010 is the lowest).

The water I use is tap water and its the same water I used when I did batch sparging and got 75% eff.

To respond to your four points:

1) pH and 5.2. I would prefer to get a strong handle on my process, then try 5.2 to see if/what difference it makes.

2) Grain mill. A grain mill is on the way. The grain crush I am currently using is the same grain crush that I used when batch sparging. The crush is whatever my LHBS (mdhb.com) has their mill set at.

3) Thermometers. My understanding from B3 is that they do not make adjustments to their thermometers. They just install them and send them out the door. Based upon their quality control measures, I have no reason to doubt this. I will check both therms against the two other therms I have.

4) Stirring. I will give this a try. I am concerned that perhaps my pump is pulling too hard on the mash causing it to compact. Right now, I have the valve from the MLT 1/4 open and the valve on the recirc sparge ring 1/4. I might try using my kettle as a grant to prevent the pump suction from compacting the grain bed.

 

[jdoiv]

Yeah, I would check those therms out. Bimetal thermometers can easily get out of whack and digital thermostats can routinely be 10* or more off. Try calibrating at the temps you plan on using them at, not at boiling or freezing points.

The more I think about it, the more I'm convinced it's either the thermometers or you have channeling issues from the grain bed getting compacted. Stir before you start the sparge and don't open the valve all the way up and I'll be you'll gain several points.

 

[DraconianHand]

OK,

Double checked both of my therms against a digital probe therm and a bimetal probe therm, and they are all +/- 2*.

Brewed today and got 65% efficiency, again.

I tried stirring the mash periodically until just before sparging. I did discover one thing at the end of the sparge. My runnings near the end of the sparge where about 1.013 and I decided to stop adding sparge water and just let the MLT run out. I tilted my MLT toward the bulkhead and instantly the wort darkened up. It appears that there is quiet a bit of sugar trapped under the false bottom. I don't think it is 10 points, but still.

Part of me is happy that I am getting consistant results, but I am still irritated that my efficiency has taken a hit.

My grain mill came in on Friday, so maybe I can make up some of the difference by adjusting my crush.

 

[jdoiv]

Do you have a pickup tube on the MLT? My 1550 came with a little copper piece of pipe with a small bend in it that goes down to the bottom and acts as a pickup tube so I'm pulling off the bottom. I'll tilt my MLT up at the end and I get cloudy runoff but not really darker run off. This could be a factor, but I doubt a really big one.

Have you tried doing a simple single step infusion batch? If not, you may want to give this a try. I found that my efficiency was not very good when I would do the HERMS thing. I don't know why, but it never worked very well for me. I do more direct fired step mashes and have good results.

 

[jdoiv]

Also, over on the Morebeer forum, there is a guy named MuddyMike that has a 1550 in Maryland. Maybe you could PM him and see if he can come over and help you troubleshoot.

 

[DraconianHand]

No pick up tube on my 1550...not yet at least. I have a short piece of 1/2" copper tubing, but the bulkhead opening on the inside of the MLT is just a bit smaller. I'll have to see if I can find some sort of fitting to reduce it just slightly.

My run off went from being very clear golden at the end of the sparge, back to the brown I saw at the begining of the sparge and at recirc. It was a bit cloudy, but certainly darker.


The fact that I have some dense wort sitting in the dead space under my false bottom indicates that I am probably getting greater lautering closer to the drain. I would imagine that a pickup tube would help prevent this.

I'll shoot MuddyMike a PM. Thanks.

 

[Boerderij_Kabouter]

This may be a silly thing to ask.... but, the inlet of your drain is below the false bottom correct? All the FB I have dealt with have a pickup tube passing through them. I am sure you have this figured out. Good luck with getting the system tuned up.

Maybe you should try a grant. You could use a kitchen pot with a siphon to the pump just to experiment and see if it helps.

 

[jdoiv]

Hey Drac, quick quesiton. How long does it take for you to raise the temp in the grain bed from say sac rest to mash out? I found that it took forever in mine, but I don't have any automation and would have a hard time maintaining any temp in the HLT. That's the main reason I haven't used it much. Way more work just keeping an eye on the temps. I still have a sneaky suspicion you are having some sort of channeling issue. Also, do you drain all of the wort out of the chiller and hoses?

 

[DraconianHand]

My FB is entirely over the top of the drain inlet, so I should not have too much of an issue getting a pickup tube in there. Good thought though...it never crossed my mind.

As to how long it takes to go from rest to mashout, I would have to say it depends on environmental temp. I use the HERMS to rais the mash temp, so it can take a while (I have not tested it)...at least 30 minutes? I think on my next brew I will try direct heating the MLT while recircing.

I expect to see an increase in eff once a pickup tube is installed. A more uniform, centralized draining of the wort should help and I will get all the wort off the bottom of the MLT will help a bit.

I will also be using my new grain mill.

70% efficiency would be nice.

 

[jdoiv]

I think you should try just doing a simple single infusion mash of 154, mash out to 168 either through infusion or direct fire (keep it really low, set up recirc, and stir constantly) and you'll see a jump in efficiency. That and the pickup tube.

Last time I set up the herms, it took forever to move up a step and my efficiency was really low at 71%. When I direct fire, I can move the temp up a step in usually less than 15 minutes and get high 80's low 90's efficiency.

 

[jdoiv]

You know, thinking about it, I wonder if the additional water in all the hoses and coils dilutes the enzymes making conversion take longer? Do you do a starch test? I never do on the single infusion or direct fire mashes, as I usually go for a good 75 minutes. But I should when using the herms. Just a thought.

 

[DraconianHand]

jd,

I don't think that any water in the hoses or coils would affect the enzymes, if it isn't in the mash tun during the mash, it shouldn't have an effect on the mash.

And to answer your previous question about wort in my hoses and coils...there isn't any. When I begin my sparge, the water from the HLT goes to the pump, through the heat exchanger in the HLT and out on top of the mash. Any wort in the system is pushed out an into the MLT.

For future brews, I am going to change one variable at a time, so I can see what effect (if any) it has on my efficiency. I think this will be my plan:

1) add pickup tube
2) change my crush
3) direct fire MLT from rest to mashout
4) stop adding sparge water early and run MLT dry
5) 5.2 additive to mash
6) grant (if my eff isn't good enough)

I'll post the results on this thread. Everyone's ideas are well appreciated, thanks. When my membership is up, I'll be upgrading to a lifetime membership.

 

[Brew-boy]

I have done it both ways and I have not noticed a difference, so now I calculate how much water is needed for sparge and drain the MLT dry to get my volume. This saves me water which I have to buy and build.

 

[DraconianHand]

Maybe I'll try the 5.2 before I go running the MLT dry, then.

If I don't see an increase in efficiency after trying something, then I will just shelve it until later (for when I get real desperate).

 

[AiredAle]

You mentioned you get your grain crushed from the same LHBS that you did while batch sparging. I would suggest that maybe their mill gap changed at some point, or the mill itself was changed unbeknownst to you. This would account for some of the difference. Did you also change the base malt you use? Could this malt be crushed more or less efficiently? Just some questions to get you thinking if you left any variables out of your long list of things to try.

Good Luck!

 

[DraconianHand]

I am hoping to check the setting of the rollers at my LHBS tonight and I'll ask them if the setting has changed at all.

The base malts vary from recipe to recipe, but I have brewed several recipes on both my stovetop system and my B3 system. In both cases the efficiency dropped 10-15% on the B3 system.

 

[DraconianHand]

First brew using my new mill. Went from 65% eff to 75%.

I check the rollers at my LHBS and found them to be .42 and my new mill at .39. I didn't notice any negative effect on sparging from a finer crush, so I may adjust my crush further.

It also looks like a pick up tube won't work with my false bottom. Apparently MoreBeer had problems awhile back with the false bottom supports bending under a heavy grist, so they added more supports. These supports prevent me from getting the false bottom in place with a dip tube. For now I will just tip the MLT to get the heavy wort from under the false bottom.