You might have seen in recipes the use of rice hulls. And when you see rice hull in a recipe you might be asking your self, “What are rice hulls and how do I use them?”
The Answer To Your Question…
Rice hulls are the protection covering of rice. For homebrewers these can be a great tool for when you plan on brewing all-grain. If you do all-grain brewing you use them as make shift springs. When adding them to your mash they will get in-between the wheat or flakes and prevent clumps forming. So picture them as little tiny springs making your mash fluffy rather than a big pile of goop. Rice hulls can be added directly to your mash and they add no flavor or color to your beer, they are just an aid to help with preventing stuck sparges.
If your recipe does not have a large amount of barley in it and has primarily wheat, rye, or flaked whatever then it is usually a good idea to use rice hulls because without them it turns into a big dough ball.
How much should you use?
Typically people will use 8 oz to 1 lb per recipe when they are put to use. One thing that you need to consider is, while they do not add flavor to the beer or color you do have to account for water absorption. One way to minimize this is soak/rinse your rice hulls in water before adding it to your mash. I have found that this helps while mashing.
I sometimes recommend for people who making their first all-grain batch to use rice hulls even if their recipes doesn’t have a large amount of flaked whatever or wheat or rye. It will just help prevent a stuck sparge in general.
Conclusion
While rice hulls aren’t necessarily needed in recipes they can be used as a great tool to prevent stuck sparges.
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Jay's Brewing Blog 
April 4, 2012 at 10:40 am
Excellent, thank you. I had to dump a Blue Moon clone due to this issue… will make sure i get the rice next time. 🙂
April 4, 2012 at 11:08 am
It can be helpful sometimes. You’ll be ready this next go around!