Rice Hulls are the outer shell or husk of a grain of rice. Rice Hulls are normally removed from the grain of rice, and when used for brewing the hulls improve the filter bed of the mash to decrease the likelihood of a stuck mash. Rice hulls are non-fermentable, and provide bulk helping prevent the mash from settling and becoming stuck during the sparge. Rice hulls are particularly useful for recipes using high protein additives such as large amounts of wheat or flaked barley or rye in the grist.
Brewing Use Guidance:
Rates of usage can vary with the percentage of adjunct grains, but in general, adding between 1% and 5% of total grist weight in rice hulls directly to the mash helps ensure better wort runoff rates and greater wort clarity.
In an all-grain brew Rice hulls act like makeshift 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 colour 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 250 gram to 500 gm 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 colour you do have to account for water absorption. One way to minimise this is soak/rinse your rice hulls in water before adding them into your mash.
Sample Brew Recipe:
The Following homebrew recipe is for a 25 Litre brew length:
OG 1.048 Colour 6.7 EBC Est. Abv 4.9 Target IBU 10-12
Use your favourite classic style German Pilsner or Czech Pilsner Hops or some modern New World NZ Hops or AU Hops for a new world twist and hop to between 25-45 IBU. The following varieties maybe of interest:
You can use a liquid Yeast or a dried yeast from the large stable in the shop. Some suggestions to think about below: