First AG... classic efficiency is not what I want

[shushikiary]

Well, I pretty much knew this was going to happen... first AG batch hit 60%(note this is the brew house efficiency).. I know I know, I'm being the clasic perfectionistic self that I am and would like higher efficienty.

I did a fat tire clone. 11.375 lbs of grain with 1.25 q/lbs mash. My system is a completely automated one I built up from the ground up using the brew troller. It fly sparges, automatically. I litterally put the grain in tell it to go and add hops. It's a RIMS system also. I sparged at 175 deg, mash showed that at the end of sparge it was down to about 155 deg, temp in the kettle was about 140. I sparged at 1 quart/min which I know was the rate as it's measured by the brew troller for automation. The batch was a 5 gallon batch with a preboil volume of 6.355 gallons. I know that I boil off almost exactly one gallon in a hour (it was an hour boil), and then .2 gallon for density increase while cooling.

I did a 20 min dough in at 110, 45 min sach at 154, then 10 min mash out at 168. Like I said, fly sparge. Sadly I measured my mash PH and it was 5.6

Currently I have no sparge arm, I just have silicone tubing laying in the top of the mash. Now my pump that pumps from the HLT to the MLT has a pretty scary high flow rate and sense I dont have a sparge arm and just let the tubing sit in the top of the mash I'm slightly worried about channeling. I'm using a false bottom in a 3 keg setup.

I currently have my own grain mill as well and have the gap set to .035, it's a 3 roller mill and I condition my malt, I get a very nice crush without shattered husks. When I poured the grain into the mash tun I got a TON of "dust" that came up, I'm wondering if perhaps that's an issue as well, I put the grain in slow, maybe I should put it in faster next time, or slower, what ever reduces the dust. I also ran the grain through the mill only once.

Also I should note that I did no stiring what so ever at any time during the brew.

So, I'm thinking to get my efficiency where I want it, more like 75 - 80% or higher I'm going to try a sparge arm, lower my mash PH with salt additions and or saurmauls, and then actually stir during the mash. Should I also make my crush even smaller? I've read that .035 is pretty good, maybe I should run the grain through a 2nd time?

Anything you can offer to what I'm doing would be nice. Sorry for the long read, I wanted you to have all the details.

 

[lgoolsby]

If you didn't stir the mash when you first 'doughed' in then that would certainly explain low efficiency. The grain will tend to form dough balls that, if they ever do soak through on their own, would take a long time to do so. Did you use iodine to test for full conversion?

 

[shushikiary]

No, we never did an iodine test either. I'm really thinking that the no stiring is what really did us in. I'll look into doing an iodine test, that or just making sure our mashes always last long enough.

 

[IrregularPulse]

I second stirring at dough in.

 

[bruin_ale]

yep, stir the mash. Crush gap sounds about right, I wouldn't worry about the dust - that comes with the territory. Probably not related to your efficiency, but why the acid rest?

 

[jfowler1]

I think it is pretty obvious that your process let you down due to the no stir mash. You don't have to keep stirring after you have your temps set, but you really need to stir while adding strike water to eliminate those dough balls. Honestly, I am shocked that you didn't have an awful time with a stuck sparge considering the lack of stirring.

Next, the sparge arm. I do not think it is worth wasting your time building a contraption that "rains" down, or "twirls", or any other of the Whoville style designs on the market. Just provide a tube above the grain bed that can keep adding water during the fly sparge. If anything, a slight whirlpool motion above the bed might be nice. Don't overthink that one. I cringe when I think back to drilling all those little holes into a copper tube.....

Finally, lets play worst case scenario. You stir your next mash really well, run your program, carefully measure your volumes, and still get 60% efficiency. Are you selling beer commerically and looking to make a profit? Are you unable to fit enough grain into the mash tun to make the recipe you are going for? If the answer to these questions is NO, don't sweat it. People get very hung up with efficiency numbers. They should be hung up with consistency numbers. Brew at 60% every time, and you are doing better than someone who pulverizes his grain, gets 95% one time, 82% the next, and experiences a stuck sparge on his third batch. It is just a number - the important thing is knowing what that number will be, not how high the number is.

High consistancy and low lag times are two things that are constantly bragged about, but have very little to do with making a good beer.

Joe

EDIT - I just saw the bit about too high a flow rate between the HLT, the pump, and the MLT. It is an easy fix. Do you have a pump with a magnetic drive (like a March pump) that can be throttled down while still running? If so, I suggest adding a BV to the inlet point of the MLT, so that you can throttle the flow rate back into it (in other words - 2 BV's on the mash tun, one for the outlet, one for the inlet). It makes controlling the sparge speed easier because valve adjustments can be made at eye level, makes strike temps easier to hit, because the hot water can be regulated by a valve at your fingertips, and makes recircuating a mash easier, because you can have the outlet on the mash tun, the inlet on the pump, and the outlet on the pump fully open (so the pump does not get choked off) but still keep the recirc speed controllable by the valve on the MLT inlet, which eliminates the threat of overly compacting the grainbed during recirc. That was a long way of saying add a valve to your system.

 

[shushikiary]

Yea I have a flow control valve on the RIMS tube out just before it goes back into the MLT. I however do not have one on the HLT pump out to the MLT in, I'm thinking I may add one for this very reason.

Oh, and yes I have 3 pumps. 2 are LG pumps, the fast one is the 3-md-hc which goes from HLT to MLT and does 12gpm, and the 2nd one is a 3-md-hc-te which is 3gpm slower and is used for MLT recirc and boil recirc to sanitize the plate chiller. The third is a peristaltic pump I built for 100 bucks that lets me control the sparge flow rate in a linear fashion as I PWM control its 12v DC motor with the brew troller.

So I'll add a flow control valve to the list for HLT out to MLT in, drop the sparge arm and maybe lengthen the tubes in the MLT so I can coil them on top of the grain.

I did research on stuck sparges and mashes before this and that's why I crush my grain and condition it like I do, to help prevent that, so I'm glad my prep in that sense worked!

If stiring ends up fixing my efficiency issue then I'll most likely put in a motor and control it with the brew troller to automate that as well, haha.

Oh, and I didnt really do an acid rest per say, but the temp and time were right to call it that I suppose. I did a dough in just to make sure it would recirc like I wanted before going head long into the sach rest.

I know that I dont NEED to fix my efficiency numbers, I'm just being a perfectionist I suppose. That and my friends keep talking about actually turning this into a full brewery someday sense people keep asking es if we sell the beer after they try it, or where they can get more of it. So just in case that ever did happen I'd like to do what I can to get the efficiency up there (who knows what happens 5 years from now, haha). Given that the system pretty much runs its self at this point I'm hoping it should have consistent efficiency, we'll find out. I'd love it if I could get 75 - 80 % consistently, but then again I like a challenge.

Thanks for the replies, any other idea's I'd love to hear as well so I have a list of things to try and exhaust in an attempt to get what I want.

 

[shushikiary]

Ok, update time.

Brewed again, same recipe but with 2% saurmaulz added to get the right PH for the mash. I stired like crazy at dough in and mash out. I got my mash PH DEAD on this time 5.2. I also made the flow during fly sparge much lower and made my silicone tube much longer to have it coil around on top of the mash, had a nice little circular flow on top of the grain bed. I also lowered my crush to .030 from .035.

And.... EXACTLY the same efficieny. I'm talking not even 1% lower or higher. So that's both good news and bad news, good because it's VERY consistant, bad because the efficency is not as high as I'd like it.

So I got to thinking about this... My false bottom is this one:

http://www.midwestsupplies.com/11-sanke-stainless-steel-false-bottom.html

I'm starting to wounder if perhaps it isnt the culprit. It doesnt cover the entire bottom of the keg, only 11 inches of the some 15.5, and not only that but it can only pull from about 9 of those 11 inches it is wide, and it also only pulls from the top really, the sides get cloged up with grain pretty quick during the mash.

Other then that I'm running out of idea's as to why the efficiency is so low, I could perhaps increase the time of the mash from 45 min to 60 or something. Still didnt do an iodine test. I could also test the gravity of my sparge runnings, it's possible that I should sparge longer and then boil more, for a 5 gallon batch I start with a preboil volume of 6.3 gallons, so with 11.625 lbs of grain and 1.25 q/lbs I use 3.6 gallons for mash, then another 2.7 gallons for sparge... so not a very large sparge volume. Perhaps a larger sparge volume and longer boil will solve the problem... hmm.

The grain bill was as fallows, just for added info (it's a BYO fat tire clone plus the saurmalz):
8 lbs 10.0 oz Pale Malt (2 Row) US (2.0 SRM) Grain 74.19 %
8.0 oz Biscuit Malt (23.0 SRM) Grain 4.30 %
8.0 oz Cara-Pils/Dextrine (2.0 SRM) Grain 4.30 %
8.0 oz Caramel/Crystal Malt - 20L (20.0 SRM) Grain 4.30 %
8.0 oz Caramel/Crystal Malt - 40L (40.0 SRM) Grain 4.30 %
8.0 oz Munich Malt (9.0 SRM) Grain 4.30 %
4.0 oz Acid Malt (3.0 SRM) Grain 2.15 %
4.0 oz Chocolate Malt (350.0 SRM) Grain 2.15 %

 

[JuanMoore]

Going from no-stir at dough in to "stirring like crazy" combined with a finer crush should absolutely result in some sort of increase in efficiency. How are you measuring your volumes, SG, and temps? Even slight innaccuracies in your measurements can throw off your efficiency calculations quite a bit.

I could also test the gravity of my sparge runnings, it's possible that I should sparge longer and then boil more, for a 5 gallon batch I start with a preboil volume of 6.3 gallons, so with 11.625 lbs of grain and 1.25 q/lbs I use 3.6 gallons for mash, then another 2.7 gallons for sparge... so not a very large sparge volume.

Collecting more wort and boiling for two hours doesn't really solve the problem, it just makes up for it. It's usually cheaper and easier to buy an extra pound of grain and live with a lower efficiency. Your sparge volume seems fine to me (it's more than 2.7 gal BTW). If anything I'd guess that a thinner mash (like 1.5 qt/lb) and less sparging would be more likely to increase your efficiency, especially if your false bottom is the culprit like you're thinking.

Checking the gravity of both the first runnings and last runnings could very well answer the question for you. You could also try a double batch sparge. If your efficiency improves with batch sparging then it's most likely the mash tun/false bottom design causing channeling that's the issue.

Edit:
I also want to reiterate what jfowler mentioned about chasing efficiency. At the homebrew level consistency and quality are way more important than efficiency. I've been able to achieve very high efficiencies, but it was somewhat inconsistent and I even went so far that I had tannin issues on one batch. I'd much rather buy an extra pound of grain and brew great beer every time than be able to say I get 90% efficiency brewing an inconsistent or sub-par beer. IMHO dialing in your current system with lower efficiency will help you more if you end up going pro than trying to maximize efficiency on it. Even at the small brew-pub level efficiency isn't all that important.

 

[Bobby_M]

It's very possible that your high PH was due to a good portion of the malt being taken out of the buffering equation by being locked up in dough balls. I'm not saying it's not due to the water chemistry and specific grain bill, but you should try to only change one variable at a time.

One thing doesn't jive though: "I start with a preboil volume of 6.3 gallons, so with 11.625 lbs of grain and 1.25 q/lbs I use 3.6 gallons for mash, then another 2.7 gallons for sparge"

If you strike with 1.25qt/lb at 11.625lb of grain, that's 14.5 quarts and due to absorption, it really only leaves about 8.75 quarts (just under 2.25g) available for runnoff. You should be preparing at least 4 gallons of sparge if you want to allow the bed to run dry, but you'll get better efficiency if you run the full sparge with the bed fluid. That means running in about 6 gallons of sparge water even though you stop running off when you reach 6.3 gallons preboil.\

It sounds to me like your volume measurements might be off. You're not adding any topoff water to the fermenter are you?

 

[Yooper]

I'd prefer a pH of 5.4-5.6 anyway, so that was great in the first batch.

I might have missed it, but how was your crush?

 

[JuanMoore]

One thing doesn't jive though: "I start with a preboil volume of 6.3 gallons, so with 11.625 lbs of grain and 1.25 q/lbs I use 3.6 gallons for mash, then another 2.7 gallons for sparge"

I was hoping he's doing a proper fly sparge and just doesn't understand the numbers behind it. If he really is trying to sparge with < 3 gal of water, then there are bigger problems than efficiency going on.

 

[shushikiary]

Well first my crush looks perfect. It's exactly like the pictures on the wiki for malt conditioned grain that was crushed. The husk is very much intact, almost split down the middle but still one piece so you can see what is inside but didnt destroy the husk.

I dont top off any water in the fermenter, infact it's pretty much exactly 5 gallons. The system is calibrated and measured to be accurate on volume down to about .025 of a gallon.

I've never done all the water equations my self, the brew troller takes care of that so I'll go through what it does.

We start off with 9.4 gallons of water in the HLT, pump more than the 3.6 into the mash tun based on the mash tun dead space and grain absorbtion, leaving about 4.8 gallons in the HLT when mash starts (this number is a vague recelection of mine, I know it was under 5 gallons and greater than 4.5). Then we mash, and then start sparge.

At sparge the paristaltic pump slowly ramps up to speed until we hit 1 q/min. Every time 1 quart is transfered from the MLT to the kettle 1 quart is then pumped from the HLT into the MLT by turning the pump on, the transfer from HLT to MLT usually takes about 5 - 10 seconds, so much faster than the output, but with the flow control valve on there now it's much slower than it was before on the first brew and now goes into a circular motion on top of the grain bed instead of into the grain bed with the longer silicone tube on it.

After the HLT is empty (about .25 gallons of dead space) the MLT starts to get drained. The water level goes below the top of the grain bed, but the MLT is not fully drained, usualy it goes down to about 2/3 of the height of the grain bed by the time we hit the 6.3 gallons in the kettle.

So I guess that would really mean we sparged with closer to 4.5 gallons of water, and took 6.3 gallons out of the MLT and into the kettle.

Hope that clears some things up. I got the 2.7 number by looking at the amount of sparge water taken out of the MLT into the kettle, by subtracting the 6.3 - 3.6 for the mash water.

I should also note that it has been noted on the brew troller forums that the calculation they do for grain absorbtion is very conservative in that they assume the grain will absorb much more water than it does... Now that I've explained all this out, perhaps forcing that value lower would increase efficiency by not leaving so much water behind in the MLT. I also have not yet measured the gravity of the last of the runnings durring sparge, might be a good idea to do that to see if perhaps that is where the efficiency is lagging, idk.

 

[shushikiary]

I'm starting to wounder if maybe I'm sparging too fast as well. At 1q/min I get done in about 25 minutes for sparge on a 5 gallon batch. I see a lot of people talking about 45 min sparge.

Also, I recirc pretty fast during mashout and mash. I've noticed that the grain bed is fairly compacted at the bottom. By that I mean that the grains get stuck into the false bottom pretty good and clog it up, but because I have enough of a vacuum from the pump running it forces its way through. The peristaltic pump does this as well, sense it can actually suck the input side liquid uphill for more than 20 ft of head.

So what I do is recirc during mash out and that gets the grain bed fairly compacted, then start sparge. Are the grains supposed to be fairly free floating during sparge and not stuck against that false bottom? If that's the case then perhaps we need to shut the pump off during mash out and stir a lot to get everything loosened up and then start sparge very slowly and maybe slow sparge down.

I've been reading about how to trouble shoot this some more and I'm reading that I need to measure the first wort gravity to get an idea of my mash efficiency, then after the fly sparge is done fill the mash tun back up with about 1q/lbs of water and stir a lot to try to figure out what my lauter efficiency is to see which part is having the problem.

I should note that during the mash and mash out I'm recircing at something like 5-6 gallons per minute, then once the grain bed compacts I'm closer to 1-2 gpm. I'm starting to think that maybe I need to slow this down a lot.

 

[Yooper]

I've battled grainbed compaction problems myself! A couple of things that work- start slow with the recirculation, and then increase. And, RICE HULLS! I went through much angst with the grainbed compaction issue, and found that adding about .25 pounds of rice hulls to a regular batch helps tremendously! The grains should be "loose" so you can rinse them- that's the purpose of the sparge, after all.

You could try batch sparging one batch. That will tell you if the problem is lauter/sparge related vs. mash related.

 

[shushikiary]

Yea that thought crossed my mind.

I can keep a higher flow rate if I use a larger false bottom as well, as the vacuum pressure would go down as the same amount is applied over a larger area...

I think I'll try reducing the flow rate with a valve to under 1 gpm and see what happens that way. That or try the rice hulls first, haha.

If the problem is a grain compaction issue from mash, then batch sparge would show that for sure. I'll have to figure out what I want to do...

 

[shushikiary]

Ran a test with just water... my grain mill is currently down so I cant test a brew.. the motor simply does not have enough torque and keeps seizing (it's 45 inch pounds but I geared it down to 1/2 RPM for 90 inch pounds, it's a 3 roller mill and my conditioned grain seems hard to crush, dry is fine). So I got a 120 inch pound motor at 115 RPM that I can still gear down to half if I need to and get 240 inch pounds of torque (that's 20 foot pounds!) if it doesnt have enough torque... nothing will.

Anyways... At no restriction with just water there is a rather large suction across the false bottom. So I turned it down and measured it (restricted the output of the pump after the RIMS tube) to 1 gpm, and there is next to no suction on the false bottom now while its running.

I'll report back after I get the grain mill back up and run a brew with rice hulls and this lower recirc speed.

 

[shushikiary]

Ok, reporting back. New grain mill motor is awesome, problem solved.

Attempted to brew thursday night... kept scorching wort and blew 3 heatings elements... lesson learned DO NOT restrict the flow out of the RIMS tube, only on the input of the RIMS tube. Fixed this and brewed tonight with lower flow rate.

Stired during the ENTIRE mash with rice hulls. Found that large clumps of grain where sticking together and so broke them up and kept the mash fluid. I let the grain settle gently just before the end of mash out for about 5 minutes and then sparged.

Hit mash PH perfect again. I measured the first wort gravity, 1.092, max possible was 1.096 so we got 95.8% mash efficiency. Measured last runnings, gavity was 1.021, so I could run a 90 minute boil and sparge longer to get some more sugar out. Over all, 77% efficiency this time around, original gravity of 1.064. Finally!

So I think I'm going to re-design the bottom of my mash tun to use a full false bottom instead of the smaller one that I have, and make it drain from the botom so I can put a good yet easy to fit in mash auto stir setup and that should fix the whole problem I think. Then just make sure I sparge longer on high gravity beers if I can.

 

[shushikiary]

Reporting back after 8 brew sessions.

Swiched to a HEX from a RIMS though the RIMS tube still heats the hot water for the water side of the HEX, this solved the wort scorching issues and still lets me step mash.

I switched to a sabco flase bottom to increase my area, and ran into a post on the pro brewer forums where someone FINALY posted some math on a rule of thumb for sparge rate. Rule of thumb is 1.2 minutes x lbs/sqft. lbs is the grain bill weight plus water weight in your mash tun, sqft is the sqft of your false bottom.

Given that it comes out that sparge should always be around 1/2 pint per minute on my system... I was sparging too fast.

So I reduced the sparge flow rate on the system to 1/2 pint per minute, added an automated stirer to it, AND did one other thing. For the last 10 minutes of mash out I shut off the pump and stir and let the grain bed settle. On larger grain bills I now regularly hit between 80 - 85 % (this is for grain bills of 20lbs and up), and also switched to 90 minute boils.

I've found that on smaller grain bills due to the tall but narrow nature of a sanke keg, it's almost impossible to prevent channeling with a true fly sparge. So on smaller grain bills (less than 20 lbs) if I instead let the grain bed run dry during sparge and then fill it back up again just before it completely runs dry I get a better efficiency. (essentually batch sparge, but still sparging out at the fly sparge rate).

So I figured I'd post what I found that finally got things worked out and fixed just by trial and error with some educated thought.