15 minute mash

Hey all,

I was listening to some Archives of my favorite beer radio show, The Brewing Network (http://thebrewingnetwork.com/) and there was an interview with the head brewer from TitleTown Brewery in Green Bay, WI.

He said that by using a wide and shallow mash bed as opposed to the tall compact design used by many homebrewers water cooler setups (myself included), you could achieve full mash in 15 minutes!

Apparently the guy does this now and swears by it. I use 60 minute mash on pretty much anything, and find this hard to swallow... but then again, I'm not a professional brewer (by any means).

Anyone had any experience with a shallow mash bed and these kinds of decreased mash times? I think I may give it a try with a giant tailgate cooler... 15 minutes??? Seriously?

I've read about this type of thing before. Interesting, but I have my reservations. I doubt it would work for homebrewers - I'd think you need an awfully large mash tun to make it work.

A local brewpub that I frequent actually does a 10 minute mash and 90 minute sparge. Makes good beer as well. He believes he gets less husk flavors this way but doesn't reduce his time that much. I never asked him if his grain bed is shallower than when he did longer rests. I suspect not based on his mash vessels. Did they comment if they extended their sparge time?

I've "contemplated" giving it a try but just can't get myself to tempt fate...

I wonder what the depth of the grain bed is.
I guess it will only work if you are fly sparging rather than batch sparging.

JRoche00 said:

Hey all,

He said that by using a wide and shallow mash bed as opposed to the tall compact design used by many homebrewers water cooler setups (myself included), you could achieve full mash in 15 minutes!

Apparently the guy does this now and swears by it. I use 60 minute mash on pretty much anything, and find this hard to swallow... but then again, I'm not a professional brewer (by any means).

Anyone had any experience with a shallow mash bed and these kinds of decreased mash times? I think I may give it a try with a giant tailgate cooler... 15 minutes??? Seriously?

Click to expand...

Hmm...enzyme kinetics are independent of the vessel size and shape. It is dependent on the concentration of substrate and the enzyme. 15 min mashes are possible in any shape cooler there is a vast excess of enzymes in todays grains. I've seen full conversion via iodine test in 15 minutes or less while doing decoction, in a 5 gal water cooler, and in a square cooler. Now I didn't use a spectrophotometer so there may have been some unconverted starch but since I did them all the same it doesn't really matter.

Now in theory it may be easier to get a lower water:girst ratio in different shape vessels but most people use about the same ratio. Also that would mean that concentration would be differnt and not directly due to vessel shape.

-Eric

I believe it was a 20-30 minute sparge time. I would have to re-listen to the podcast, but if I remember correctly I believe he had said that a shallow bed allows more constant temperatures throughout the mash, less husk and tannin flavoring, and greater efficiency.

Again, I have not tried it, nor am I a science whiz (in fact, my motto when brewing is... "It's ok, it's not an exact science.") but it sounds like an interesting point. I plan on trying it out and will let everyone know my results.

I've heard that conversion often does only take 15 minutes or so and the hour or more recommended for home brewing is really just "To make sure". I stick to an hour because it allows me time to weigh out my hops and set up for sparging, but I suspect that some scientific testing of the mash (perhaps a little more exact than the standard starch end point test) would yield some surprising results - especially with today's malts.

And re the "Wide and shallow" grain bed, how shallow is "Shallow"? With home brew grain bills "Shallow" would be an inch or two, but with in a commercial process "Shallow" could still mean a grain bed several feet deep. There's a vast difference - especially when we consider temp control issues.

It's all interesting stuff though!

I couldn't possibly mash in 15 minutes. I wouldn't be well enough lubricated to complete the rest of the brew

-a.

First, 15 minutes can indeed fully convert modern 2-row malt. I believe that the shallow grain bed being better issue is more for decreasing the sparge time. Deeper grain beds require slower sparges to minimize channeling. Shallower grain beds simply have less vertical distance so less chance of channeling. At least that was my take on it.
Steve
Stevenson, WA

I suspect a shallow mash for a professional brewer would be a foot or so. The few pro mash tuns I've been in have been two to five feet deep. My mashes are rarely over 6 inches.

JRoche00 said:

I believe it was a 20-30 minute sparge time. I would have to re-listen to the podcast, but if I remember correctly I believe he had said that a shallow bed allows more constant temperatures throughout the mash, less husk and tannin flavoring, and greater efficiency.

Click to expand...

the shallower the grain bed, the more likely you are to have a temp. variation - the best configuration to retain heat would be the greatest volume:least surface area, which would in a perfect world be a sphere, but the cylindrical coolers or boxy rectangles mimick that pretty well.... the shallower you go the more of a pancake effect you'll get which means greater surface area:volume which means the energy/heat will have a much better chance of getting away from things making it that much harder.....
going shallow would make for a quicker sparge tho....
just my .02

kneemoe said:

the shallower the grain bed, the more likely you are to have a temp. variation - the best configuration to retain heat would be the greatest volume:least surface area, which would in a perfect world be a sphere, but the cylindrical coolers or boxy rectangles mimick that pretty well.... the shallower you go the more of a pancake effect you'll get which means greater surface area:volume which means the energy/heat will have a much better chance of getting away from things making it that much harder.....
going shallow would make for a quicker sparge tho....
just my .02

Click to expand...

Yeah and grain density...but there is one problem with shallow. Without enough overall resistance you can cause channeling. It is very easy to channel a shallow grain bed if you draw off too fast. A larger grain bed provides greater resistance (which slows run off) but also acts to "even out" the overall hydrodynamic pressures.

-Eric

eolle said:

hydrodynamic

Click to expand...

Gawd I love that word.

eolle said:

Yeah and grain density...but there is one problem with shallow. Without enough overall resistance you can cause channeling. It is very easy to channel a shallow grain bed if you draw off too fast. A larger grain bed provides greater resistance (which slows run off) but also acts to "even out" the overall hydrodynamic pressures.

-Eric

Click to expand...

just to be clear ... i'm not *pro* shallow bed, i thought my explanation pointed that out mashing you want stable temps, meaning keeping the endges wrapped, ie the sphere comment, which in turn works with your comment on channeling/and the avoidance of it....
i luv beer

well, just do a conversion test on see if it works? i agree w/ wric and above on the shallow grain bed channeling easier and unable to hold a constant (or somewhat constant) mash temp. good questions.

As others have stated, most of the conversion is done in about 15 minutes. So, there's definatley some truth to this.

JRoche00 said:

He said that by using a wide and shallow mash bed as opposed to the tall compact design used by many homebrewers water cooler setups (myself included), you could achieve full mash in 15 minutes!

Click to expand...

I can believe full conversion in 15 minutes, particularly depending on the grains used (at least I have no reason not to). I haven't heard the program, but perhaps the speaker was implying that runoff could be accomplished faster with a shallow grainbed that with conventional geometries? There are definitely some disadvantages (less filtering), but certainly there would be less resistance with a shallow grainbed that with a thick one.

Shallower mash beds would definitely be more prone to channeling. Temperature variations with shallower mash beds would be more of a problem but mashing temperature plays a major role in the time required to complete conversion. A mash at 150 deg. F takes much longer than a mash at 160 deg. F. Regardless of the depth of the mash during lautering, you just can't rush the sparge if you hope to achieve reasonable efficiency

Alvin said:

Regardless of the depth of the mash during lautering, you just can't rush the sparge if you hope to achieve reasonable efficiency

Click to expand...

Nevertheless, a shallower grainbed will present less resistance to a gravity fed sparge than a deeper grainbed. Also, it would be possible to sparge more of the grain at one time at some optimum rate for extraction, in crossection, than with a taller, deeper grainbed. Sparging a gallon of water through a surface area of 5 sq.ft. at some constant flow rate for a given area will take less time than sparging it through 1 sq.ft.

Unless you add a pump, but that's a whole 'nother animal. And as a homebrewer I can't see any advantages for me to go to a shallow grain bed over my cooler. And that may not even be what the guy on the radio was getting at.

kneemoe said:

the shallower the grain bed, the more likely you are to have a temp. variation - the best configuration to retain heat would be the greatest volume:least surface area, which would in a perfect world be a sphere, but the cylindrical coolers or boxy rectangles mimick that pretty well.... the shallower you go the more of a pancake effect you'll get which means greater surface area:volume which means the energy/heat will have a much better chance of getting away from things making it that much harder.....
going shallow would make for a quicker sparge tho....
just my .02

Click to expand...

That's the exact reason I went with a cyndrical cooler, rather than a rectangular when putting together my AG setup. With less exposure to the outside air, I assumed that it would be easier to maintain a constant temp. I think I was right, but that's without applying heat directly to the mash.

I'll bet that if you can apply heat directly to the mash, you'll get quicker conversion with a shallower bed. Whether or not this method will produce a better tasting beer is the big question.

I'm guessing that they grind much finer than we do and since the grains are spread out more there is more filtering action from the grain bed thus preventing stuck sparge due to the large surface area.

Denny's Brew said:

I'm guessing that they grind much finer than we do and since the grains are spread out more there is more filtering action from the grain bed thus preventing stuck sparge due to the large surface area.

Click to expand...

I did some reading a while ago that initially surprised me that is tangentially related to this, but not wrt shallow grainbeds or in refutation of your point. I had assumed that all breweries (regardless of mashtun geometry) crushed grain pretty finely to get maximum extraction. Turns out that there is actually a 'sweet spot' to grind at which balances extraction from the grains with lauter throughput. In other words, as they crushed finer to get more extraction, they slowed down lautering which reduced production. Too coarse of a grind and of course they left a lot of sugar on the table, so to speak.

This may not apply to micros who have less throughput than larger brewers and do fewer batches per year...as one man sitting in my garage trying to avoid chores I often neglect the business side of the equation!

Sam75 said:

That's the exact reason I went with a cyndrical cooler, rather than a rectangular when putting together my AG setup. With less exposure to the outside air, I assumed that it would be easier to maintain a constant temp. I think I was right, but that's without applying heat directly to the mash.

Click to expand...

That's what I originally thought, but after going to my 36qt Coleman Extreme I see at most 1F drop over 75 minutes. However, I do seem to see a lot more temperature variation in the rectangular cooler vs my old 20qt cylindrical. I certainly would have opted for a 40qt cylindrical if they had been readily available and inexpensive.