How would you fix consistent, low mash efficiency?

[strangegreenman]

Hello, Homebrewtalk! I have a problem. I have been brewing all-grain for five batches now, and with one exception, always have low efficiency. I have been paying close attention to my system and its results and need some help.

How do I raise my efficiency from 50%?

Here are my parameters. If you spot something I'm doing wrong, let me know!

-I mash in a 10-gallon igloo drinks cooler with a stainless steel mesh tube at the bottom. The tube sticks out across the whole diameter of the tun.

-I mash at a ratio of 1.25 quarts per pound of grist, between 150-155*F, for 45-70 minutes, depending on the recipe. Sometimes my grains test faintly positive for starch even at the end of the mash, though the wort tests negative (iodine).

-I sparge as much as I can, but my kettle is only five gallons. Since most of my beers are relatively small (1.035- low 1.050s), I make do with this. Usually I use about 0.3-0.4 gallons of sparge water per pound of grain.

-I batch sparge, although on my most recent beer, I "hybrid fly sparged," by fly sparging with 1.75gal H2O, mixing the grain bed, and fly sparging with the other half of the water.

-My LHBS does my milling for me. I find an unfortunate number of uncracked grains in the spent grist, and I think this is my most significant problem. Briess 2-row malt and torrified wheat seem to reliably shatter and convert and I hit gravity easily, but Maris Otter doesn't seem to crack quite as well.

My last few batches went like this...

English Bitter: 4.8lb Maris Otter, 4.8lb 2-row, 1lb crystal; Batch Sparge; OG: 1.039 out of 1.045; 56% Efficient mash.

Yule Gruit: ~90% 2-row, 10% crystal and roast; OG: 1.070 out of 1.072 (supplemented with 3lb of DME); Batch Sparge; 65% efficient mash.

Sahti: 4.4lb Pilsner Malt, 4lb Rye malt, 1.25lb flaked rye, .6lb crystal; Batch Sparged, 3.75 gallons out of 5 gallons at 1.050; 52% efficient mash.

Golden Ale: 7lb Maris Otter, 0.8lb torrified wheat, 0.8lb crystal. OG: 1.032 out of 1.039, 53% efficient mash.

So... does anyone have an idea of what I can do to fix my efficiency or what kinds experiments can I do to test my system's problems?

Thank you for your help!

 

[LovesIPA]

-I sparge as much as I can, but my kettle is only five gallons. Since most of my beers are relatively small (1.035- low 1.050s), I make do with this.

What size batches do you make? It's not really a problem, but most recipes are geared to 5 gallon or 10 gallon batches. If you brew 5 gallons, then you will need a larger kettle. I would recommend a 10 gallon kettle for doing 5 gallon batches.

-I batch sparge, although on my most recent beer, I "hybrid fly sparged," by fly sparging with 1.75gal H2O, mixing the grain bed, and fly sparging with the other half of the water.

I used to do that. If you have the capability to fly sparge, then do it that way. Less work and better efficiency - at least with my setup it is. I use a 10 gallon igloo cooler with a copper manifold. I also fly sparge with a spaghetti collandar and my "brew stand" is made of cinder blocks. You definitely shouldn't feel obligated to get fancy or spend a lot of money.

-My LHBS does my milling for me. I find an unfortunate number of uncracked grains in the spent grist, and I think this is my most significant problem. Briess 2-row malt and torrified wheat seem to reliably shatter and convert and I hit gravity easily, but Maris Otter doesn't seem to crack quite as well.

Grain crush is the single biggest factor that affects efficiency. What you describe is not what properly milled grain should look like. You can either have them run the grain through multiple times (will help some) or you can buy a mill and set it to whatever you want (will completely eliminate it as a factor).

I bought a monster mill 2 and set it to 0.030 with a credit card. I get efficiencies in the low 90's. Before I brew a recipe, I have to reduce the grain bill by about 20% to end up with something that resembles the original.

 

[strangegreenman]

What size batches do you make? It's not really a problem, but most recipes are geared to 5 gallon or 10 gallon batches. If you brew 5 gallons, then you will need a larger kettle. I would recommend a 10 gallon kettle for doing 5 gallon batches.

I see! Well... I was hoping I could avoid a new kettle, since I'd also need to buy a burner instead of using my stove. I brew 5 gallons at a time. How much is that cutting into my yield?

I used to do that. If you have the capability to fly sparge, then do it that way. Less work and better efficiency - at least with my setup it is. I use a 10 gallon igloo cooler with a copper manifold. I also fly sparge with a spaghetti collandar and my "brew stand" is made of cinder blocks. You definitely shouldn't feel obligated to get fancy or spend a lot of money.

How do you use that spaghetti strainer? As a sparge arm?

Grain crush is the single biggest factor that affects efficiency. What you describe is not what properly milled grain should look like. You can either have them run the grain through multiple times (will help some) or you can buy a mill and set it to whatever you want (will completely eliminate it as a factor).

I bought a monster mill 2 and set it to 0.030 with a credit card. I get efficiencies in the low 90's. Before I brew a recipe, I have to reduce the grain bill by about 20% to end up with something that resembles the original.

OK, I could learn to love that! The LHBS mill frequently stops milling and I think has too wide a gap. I'm guessing you really like the monster mill then? Where should I look for one?

Thanks so much for your input!

 

[jakenbacon]

What temperature are you sparging at? I noticed about a 10% increase when I increased my sparge temps to about 165 from what used to be around 155 or so (based on my mash temp of the brew). That is the biggest and easiest increase in efficiency with my experience.....

 

[BreezyBrew]

What temperature are you sparging at? I noticed about a 10% increase when I increased my sparge temps to about 165 from what used to be around 155 or so (based on my mash temp of the brew). That is the biggest and easiest increase in efficiency with my experience.....

If that is happening, it sounds like you aren't mashing long enough.

 

[strangegreenman]

I sparge at 170*F, so not too much of a problem there.

If that is happening, it sounds like you aren't mashing long enough.

Hybrid dextrin rest/fly sparge?
I am considering doing 165*F dextrin rests before I sparge... but I doubt that would help all that much since I've already mashed my grain for 60min and probably fully converted the crushed part of the grist.

 

[jakenbacon]

If that is happening, it sounds like you aren't mashing long enough.

Can you explain? I have always read that the hotter water helps rinse the sugars better than using a temperature closer to your mash temps when sparging....

 

[PHDrunk]

If you want to keep your current kettle, I would recommend moving to 3.5 gallon batches. I made the made the switch and found that I can do full boils on my tiny stove, and I'm more motivated to brew more frequently and experiment in my brewing given the smaller volume of beer to manage.

As for the efficiency, it sounds like a crush problem, but I'd recommend looking at Kai Troester's work on the subject (braukaiser.com). Following his guides, you could definitively separate (and thus rule out) lautering problems from conversion ones.

If it is conversion look at your mash pH --- are you way outside the suggested range? Otherwise, stirring really thoroughly (2-3 min) at dough in increased my efficiency a lot. Finally, I also crush at the my LHBS. I tried double crushing on my last batch and that gave me a few more points for efficiency, but it wasn't drastic. I'm at about 75% efficiency batch sparging now.


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[strangegreenman]

If you want to keep your current kettle, I would recommend moving to 3.5 gallon batches. I made the made the switch and found that I can do full boils on my tiny stove, and I'm more motivated to brew more frequently and experiment in my brewing given the smaller volume of beer to manage.

As for the efficiency, it sounds like a crush problem, but I'd recommend looking at Kai Troester's work on the subject (braukaiser.com). Following his guides, you could definitively separate (and thus rule out) lautering problems from conversion ones.

If it is conversion look at your mash pH --- are you way outside the suggested range? Otherwise, stirring really thoroughly (2-3 min) at dough in increased my efficiency a lot. Finally, I also crush at the my LHBS. I tried double crushing on my last batch and that gave me a few more points for efficiency, but it wasn't drastic. I'm at about 75% efficiency batch sparging now.


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Hi! Thanks for the link and the advice! 3.5gal might be a good move for now (until I get money for a mill, a burner and a new kettle, that is!). Heck, it even means I can brew more often, and I like that! :fro:

I don't think my mash pH is all that off since it has a slight sour twinge to it when I taste it, and my water is respectably, but not horribly, hard. I do stir very thoroughly at dough in, though, and that advice is money in the bank to anyone who doesn't. I'll tinker around with what you and the Kaiser said and see what happens!

Can you explain? I have always read that the hotter water helps rinse the sugars better than using a temperature closer to your mash temps when sparging....

At about 165*F, alpha-amylase hits its optimum activity and will convert any remaining starches into dextrins (oligosaccharides a.k.a. mouth-feel/body sugars) at a furious pace. They won't ferment, but they will up your efficiency by a bit, and I think that's what Breezy was getting at. At 170*F, that rinsing goodness you mentioned takes over, and all the enzymes get destroyed in the process, too.

 

[MindenMan]

If I missed it, forgive me... I used to just hit the numbers volume wise, and my efficiency was pretty good, so I accepted it as normal and never checked the gravity of my sparging. Damn! I was leaving 1.030 gravity wort behind in my sparge tun. I have a 10 gallon BK and it was pretty full last batch with the "extra" sparging water adding to the volume. My efficiency went way up, and I still had a half gallon or so left over in the grain, so there was my starter wort. You mentioned only having a 5 gallon pot. Go to Wally world and buy a cheap pasta pot, then you have plenty of pot to boil down all the 1.015 plus extra wort you weren't getting before. I am willing to bet your numbers will drastically your first batch using the new method. For less than $20.00 you can get a 16 quart covered pot to boil down the extra gallon or two.

 

[strangegreenman]

If I missed it, forgive me... I used to just hit the numbers volume wise, and my efficiency was pretty good, so I accepted it as normal and never checked the gravity of my sparging. Damn! I was leaving 1.030 gravity wort behind in my sparge tun. I have a 10 gallon BK and it was pretty full last batch with the "extra" sparging water adding to the volume. My efficiency went way up, and I still had a half gallon or so left over in the grain, so there was my starter wort. You mentioned only having a 5 gallon pot. Go to Wally world and buy a cheap pasta pot, then you have plenty of pot to boil down all the 1.015 plus extra wort you weren't getting before. I am willing to bet your numbers will drastically your first batch using the new method. For less than $20.00 you can get a 16 quart covered pot to boil down the extra gallon or two.

OK, one vote for a new kettle, then! I think my problem's a combination of "needs more sparge" and "needs a better crush," then. Thanks for the pointer with the noodle pot, I'll see what's for sale!

 

[plankbr]

Not sure that someone hasn't mentioned this, but stir the SNOT out of it every 15 minutes during the mash. I can assure you your efficiency will bump up quite a bit.

 

[IslandLizard]

Use a 2nd kettle or large stock pot on your stove. Most stoves won't boil 5+ gallons on a single burner/element anyway.
Either split the batch or just boil down some of your 2nd or 3rd runnings in the 2nd kettle. Then combine the 2 in your fermentor. I do that.

As mentioned before, to beat your low efficiency you need to get a much better crush. If you see whole uncrushed kernels, 50% of your grist is "under-milled."

The iodine test is only showing the conversion of starches in the wort. It won't detect the starches that are still locked deep inside the large granules, where the water and enzymes can't get to.

Let your HB shop run it through twice will help somewhat, but is still not fine enough. Or get them to tighten their mill (yeah right!).

Better yet, invest in your own mill. I vow for a Monster Mill MM2 but there are others. To save some money on the MM2 you could make your own baseboard and hopper. There's always the Corona.

 

[wilconrad]

OK, one vote for a new kettle, then! I think my problem's a combination of "needs more sparge" and "needs a better crush," then. Thanks for the pointer with the noodle pot, I'll see what's for sale!

Use the ol' 3-step process before you go out and buy new kettles/equipment:

Step 1: Fix the crush
Step 2: Fix the crush
Step 3: Fix the crush

 

[clickondan]

My opinion, something you can easily change immediately and could help considerably: Your sparge and boil volume is limited by the kettle size, and your crush may not be ideal. Assuming you don't change either of those conditions, if I were you, just for a test, I'd only change one factor... Stir like it's saving your mom's life, at every single key point in the mash. Stir vigorously at dough in. Stir vigorously at 10 min. Stir vigorously at 20 min. Give it a rest now because of diminishing returns. Stir vigorously 5 minutes before lautering. Vorlauf a bit more than you'd have to if you didn't. Stir your sparge like Jesus is coming back. Side note: I'd sparge with 180F water in your situation. I did these things without changing anything else and went from 62% brewhouse to 73%.

 

[cluckk]

Ding ding ding ding ding! We have a winner: Quote "-My LHBS does my milling for me."

Invest in a mill and grind your grain finer. This will raise your efficiency better than anything.

 

[max384]

Besides the overwhelming response to mill your own grains, you've got to get a bigger brew kettle, and likely move to a propane burner. I'm assuming that your boil off rate is really low on the kitchen stove, and that you have to add water and the end of your boil (because I can't see how it's physically possible to boil five gallons in a five gallon kettle without significant spillage). You're going to increase your boil off rate by moving to a proper propane burner, which means you'll use more sparge water. More sparge water means more sugars extracted from the grain, which will lead to higher efficiency (plus a finer crush, of course).

 

[DurtyChemist]

I'd consider brew in a bag and do the whole thing in one pot. Thinner mash might give you more enzyme activity. Either that or buy a bigger kettle or just do extract.


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[Riot]

If you want to see if more sparge volume will help without having to buy anything, try a thicker mash. Get to 1 or 1.1 qt/lb, should get you at least another couple pints of sparge.

 

[Denny]

-My LHBS does my milling for me. I find an unfortunate number of uncracked grains in the spent grist, and I think this is my most significant problem. Briess 2-row malt and torrified wheat seem to reliably shatter and convert and I hit gravity easily, but Maris Otter doesn't seem to crack quite as well.

There's your problem. Fix that before you try the more esoteric stuff. I average 85% batch sparging and there's no reason you can't too.

 

[strangegreenman]

I'd consider brew in a bag and do the whole thing in one pot. Thinner mash might give you more enzyme activity. Either that or buy a bigger kettle or just do extract.

Good point, though I did BIAB for a while at about the same efficiency and I find it's not quite my cup of tea mug of mead

If you want to see if more sparge volume will help without having to buy anything, try a thicker mash. Get to 1 or 1.1 qt/lb, should get you at least another couple pints of sparge.

I think that also makes a less fermentable wort by making beta-amylase less favorable... or so say my books. This would work for my Bitter and Milds, though!

Use the ol' 3-step process before you go out and buy new kettles/equipment:

Step 1: Fix the crush
Step 2: Fix the crush
Step 3: Fix the crush

ROFLMAO
Point taken.

My opinion, something you can easily change immediately and could help considerably: Your sparge and boil volume is limited by the kettle size...[snipped for length] Stir your sparge like Jesus is coming back. Side note: I'd sparge with 180F water in your situation. I did these things without changing anything else and went from 62% brewhouse to 73%.

Thanks for the details! How do you deal with the drop in temperature from stirring that much? Boiling water? That said, I hear mash mixers are all the rage with craft/commercial craft breweries. I can imagine that mixing would really improve enzyme/substrate contact, too. OOC, do you get a lot of tannic flavors with 180*F sparging?

Many, many thanks to all of you! I see I have a fairly straightforward problem with volumes and crush. I checked some grain I had lying around, and I find that Crisp 2-row gets perfectly crushed. I am not sure, but it may have been the crystal 40 in my last brew that didn't crack :? If not, then MO doesn't crack well at LHBS. Guess which two aren't going to go into my Brett IPA until I get it worked out? (The crystal's never going in that beer anyway.)

Anyway, I see that I need to stick with smaller batches until I can start to expand my equipment into a monster-mill and a big pot (I just discovered I have a big-burner propane stove in the garage! ). I really appreciate all of your advice and I'll keep it in mind for next time. Big cheers, and thanks for your input!

-Strange Green Man

 

[RM-MN]

Are you willing to put a few bucks and some labor into increasing your efficiency? Your own grain mill will likely do this but the big roller mills seem a bit expensive when you aren't sure if that will fix the problem (although it probably will) so start with something cheap and find out if the crush is the problem. If it solves the problem, you will pay for the investment quite quickly in the lower cost for the grain and if it doesn't, you don't have a huge investment in the wrong tool. I use a mill like this for BIAB and normally get about 85% efficiency but I don't have mine motorized so I have to work a bit to mill the grain. http://www.discounttommy.com/p-189-...er-for-wheat-grains-or-use-as-a-nut-mill.aspx

 

[smyrnaquince]

If I am using the LHBS mill and I can adjust the gap size, what is a good way to check that gap size? 1-, 2-, or 3-credit card thicknesses? Something else?

I use a bazooka tube, so I am not too worried about a stuck sparge.

 

[GotPushrods]

If I am using the LHBS mill and I can adjust the gap size, what is a good way to check that gap size? 1-, 2-, or 3-credit card thicknesses? Something else?

I use a bazooka tube, so I am not too worried about a stuck sparge.

A credit card is about 0.030" and is a nice tight gap. I've heard of plenty of people using one as a guide. Although a set of feeler gauges is pretty cheap, and handy to have.

 

[wilconrad]

If I am using the LHBS mill and I can adjust the gap size, what is a good way to check that gap size? 1-, 2-, or 3-credit card thicknesses? Something else?

I use a bazooka tube, so I am not too worried about a stuck sparge.

1 credit card thickness is a good place to start


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[Denny]

If I am using the LHBS mill and I can adjust the gap size, what is a good way to check that gap size? 1-, 2-, or 3-credit card thicknesses? Something else?

I use a bazooka tube, so I am not too worried about a stuck sparge.

Gap size doesn't matter and it will be different for everyone. Quality of crush is what matters. Learn what a good crush looks like and adjust from there. Nearly all the kernels should be cracked open and there should be a fair amount of flour.

 

[IslandLizard]

Needed gap size for a good crush depends on the mill. The typical 1.5-2.0" 2-roller knurled ones many home brewers and some mill it yourself brew stores use, should start at around 0.034", the thickness of a regular credit card (use an old one). It should fit just snugly.

3-roller mills are more complicated as the final crush is on the 2nd gap. I have no experience with those.

I agree with Denny that you should know what a good crush looks like. And it depends on your system too. BIAB can be a lot finer than conventional mash tuns.

EDIT: Google Results

 

[broadbill]

Invest in a mill and grind your grain finer. This will raise your efficiency better than anything.

Or simply find a vendor who provides a good crush....I can vouch for Brewmasters Warehouse's crush. All of the the major online places will also have a good crush.

 

[LovesIPA]

Or simply find a vendor who provides a good crush....I can vouch for Brewmasters Warehouse's crush. All of the the major online places will also have a good crush.

Buying grains online and paying for shipping is not always economical for everyone.

Compared to what you'll pay for grains by the pound plus shipping costs, buying base malt by the sack and grinding it yourself would pay for a mill pretty quick.

And before anyone says "but so-and-so has free shipping", there is no such thing as free shipping. Even if they don't tack on an additional shipping charge to your order, you are most assuredly paying for shipping anyway. If vendors ate shipping costs they would be out of business.

 

[jmitchell3]

I'm new to all grain, I've completed 5 batches now. Had low efficiency on my first batch, fixed it with my second. I did 4 things: 1) I bought a mill and crushed my own grain, 2) increased my sparge water temp from mash temp (152f) to 170f, and 3) looped the tail in my mash tun rather than leaving it straight, and finally 4) lengthened my lautering time. It usually takes at least 15 mins for first runnings, and over 30 mins to drain second runnings (3 gallon batches). Mash efficiency went from 55% to 72%. I've gotten between 74% and 80% since then.

From my experience, I'd recommend a few things. First, triple check your volumes. If your volume measurements are off, it will affect your mash efficiency calcs. Second, check out http://www.brewersfriend.com/brewhouse-efficiency/ for great definitions of efficiency in various stages of the brewing process. Folks are usually referring to "pre-boil efficiency" when they use the term "mash efficiency". Finally, I'd echo what others have said, your crush may be the issue. You want fine, but not too fine. Husks should still be intact and not in shards. Also, think about possibly tweaking your manifold in your mash tun. I use a 5 gallon igloo, so I've got significantly less surface area than you...a tail may not be sufficient to provide adequate flow when lautering.

Again, take all this with a grain of salt, as I'm way less experienced than a lot of these folks. Keep us posted on your progress!

Happy brewing!