[tomsawyer]

In thinking about it, its probably better to add them in such a way that they get well mixed into the grist.  They're basically replacing the husks on grain that have none.  Having them at the bottom means you have a cake of stuff above that won't let wort through.  When interspersed they allow the mash cake to be porous.

[Podo]

i used them occasionally when brewing with wheat or rye, but ever since I learned about malt conditioning on this site, IMO they are no longer necessary.

[majorvices]

I've never had a stuck runoff, so I've never had a reason to use them.

+1. I brew a beer with 50% wheat very regularly (weekly in fact) and never use them and never have a problem. That said, YMMV.

[bearcat]

i used them occasionally when brewing with wheat or rye, but ever since I learned about malt conditioning on this site, IMO they are no longer necessary.

+.5  -should clarify I use a sabco keg with their false bottom..  I went from Denny's cooler method so I could direct fire my MT.   Didn't need them with Denny's setup as well.   I have a big bag just sitting there #5pounds is huge... maybe if I forget to malt condition someday I will need them again in a panic. 

[boganbrewer]

I use rice hulls in almost all my brews because they greatly improve the circulation in my mash tun.

[lazydog79]

Rice Hulls = sparge insurance

I use 2-3 handfulls for every mash, 4-5 when using wheat or rye.

+1 I'm efficiency obsessed so I push my crush to the edge.  A friend of mine once said, "Crush 'til you are scared."  For what rice hulls cost, a couple handfulls are better than spending an extra hour lautering.

[denny]

+1 I'm efficiency obsessed so I push my crush to the edge.  A friend of mine once said, "Crush 'til you are scared." 

Hey, that's my saying!

[dbeechum]

Hey, that's my saying!

Were you his friend once?

[bluedog]

I split 50 lbs of rice hulls with 2 other guys about 2 years ago. I brewed about 50 gallons of german wheat beers that summer. I threw in a couple of pint glasses worth into every batch and never had a stuck sparge. I also made a wheat wine with over 10 lbs of wheat in a 5 gallon batch - that one got sticky but I got it going after adding a pound of rice hulls and re-mixing. By the way rice hulls come packed compressed - it's like opening a bag of peat moss...

[Tim McManus]

Will rice hulls help prevent a stuck sparge on large mashes?

We have an issue when we use over 35# of grain in our mash tun.  It's a converted keg, and occasionally we'll get stuck on +40% wheat beers.

We're brewing a 41# mash for a doppelbock next weekend and decided to get 2# of rice hulls to see if it prevents a stuck sparge.  We assume that the weight of the mash is compressing the bottom of the grain bed too much and that's preventing sparge water from flowing.  Our assumption is that the rice hulls will make the mash more porous (probably the wrong word, but you get the idea) and minimize a stuck sparge.

The alternative is doing multiple batch sparges (the grain and sparge volumes can't be completely contained in the 15-gallon keg) and whirlpooling.  We're a bit OCD over efficiency and may just have to suck up getting a 60% efficiency on a 41# grain bill.  Of course with a smaller mash we could get an 83% efficiency.  I should probably gather better metrics and graph this but there's probably a point in our system where adding more grain is actually costing us more money and we're not going to reach an optimal efficiency/cost ratio (see, OCD...).

[euge]

Tried them and it took forever to go through 2 pounds. Even brewed a 70% wheat without rice hulls and no stuck mash. I think mash-bed thickness can affect one's lauter but that can be compensated for by throttling back the run (my opinion).

Straight up- I think they are superfluous and they looked pretty dirty even after washing.

[denny]

I've had a 2 lb. bag in my supplies for over 10 years.  Never needed them.

[lazydog79]

+1 I'm efficiency obsessed so I push my crush to the edge.  A friend of mine once said, "Crush 'til you are scared." 

Hey, that's my saying!

Denny Conn: Often imitated but never duplicated 

[denny]

And I think you should all thank your lucky stars for that!

[mabrungard]

The depth of the grain bed and the flow rate have a big effect on the lautering performance.  My compliments to the brewers who can brew high wheat grists without hulls. 

I run a RIMS and its pretty important to have a fairly permeable grist so that my flowrate is good.  Many RIMS and HERMS brewers probably know that the permeability of the grist actually changes during the mash.  It starts out at a lower permeability and you cannot try and push too much wort through the grist for the first 15 minutes or so.  As the conversion and soluablization progresses, the permeability of the grist increases and you can start increasing the flowrate.   Pushing too much flow through the grist can contribute to compacting the mash and possibly producing a stuck mash.

Therefore, I use hulls with high wheat grists or grists with rye.