exBEERiment | Impact Rice Hulls Have On An American Wheat Beer

Author: Alex Shanks-Abel

The husk or hull of a cereal grain is a hard shell that shields endosperm from pests and the elements. It also acts as an effective filter when lautering despite making up just 5% of the weight of malted grain. Although useful in the brewhouse, this insoluble shell has limited culinary appeal, so humans have successfully bred most grains to readily shed these hulls during processing.

One such example is wheat, the second most common grain used in brewing, which is also used in relatively high proportions for certain styles. In order to avoid a slow or stuck mash when wheat makes up a high proportion of the grist, some clever brewers thought to substitute the barley husk with rice hulls, a method that has become commonplace.

Widely accepted as contributing zero perceptible qualities to beer, I’ve used rice hulls in several batches over the years, and they’ve always seemed to do the job they’re intended for. However, I also noticed they have a distinct aroma, and this made me wonder if perhaps they were adding something unique to my beers, so I designed an xBmt to test it out.

| PURPOSE |

To evaluate the differences between an American Wheat Beer made without rice hulls in the mash and the same beer made with rice hulls in the mash.

| METHODS |

For this xBmt, I went with a simple American Wheat Beer recipe where malted wheat made up 50% of the grist.

Put On Hulled

After adding identical volumes of RO water to separate BrewZilla units, adjusting them to the same target profile, and setting the controllers to heat them up, I weighed out and milled the grain.

Once the water for each batch was adequately heated, I incorporated the grains, adding  rice hulls to just one batch.

I then checked to make sure both mashes were at the same target mash temperature.

Once each 60 minute mash was complete, I removed the grains then boiled the worts for 60 minutes, adding hops as listed in the recipe.

When the boils were finished, I took refractometer readings showing both worts achieved the same target OG.

The filled fermenters were placed in my chamber and left to finish chilling to my desired fermentation temperature of 68°F/20°C for an hour before I pitched a pouch of Imperial Yeast L13 Global into each.

The beers left to ferment under pressure in my temperature controlled chamber.

With signs of activity absent 2 weeks later, I took refractomer readings the beers were at the same FG.

I cold crashed the beers overnight before pressure transferring them to separate CO2 purged serving kegs that were placed in my keezer and left on gas for 3 weeks, at which point they were ready for evaluation.

| RESULTS |

A total of 18 people of varying levels of experience participated in this xBmt. Each participant was served 1 sample of the beer made without rice hulls and 2 samples of the beer made with rice hulls in different colored opaque cups then asked to identify the unique sample. While 10 tasters (p<0.05) would have had to accurately identify the unique sample in order to reach statistical significance, only 9 did (p=0.11), indicating participants in this xBmt were unable to reliably distinguish an American Wheat Beer made without rice hulls from one where rice hulls made up 5% of the grist.

My Impressions: Out of the 5 semi-blind triangle tests I attempted, I correctly identified the odd-beer-out 3 times, though those were admittedly lucky guesses, as these beers tasted identical to me. These are great examples of American Wheat Beer that tasted similar to a Session IPA with a touch more body.

| DISCUSSION |

Brewing with higher amounts of huskless grains can lead to issues with lautering, hence many brewers rely on the use of rice hulls to serve the same purpose as barley husks. While marketed as contributing nothing in the way of perceptible characteristics, some of questioned this claim. Indeed, tasters in this xBmt were unable to reliably distinguish an American Wheat Beer made without rice hulls from one where rice hulls made up 5% of the grist.

While rice hulls on their own posses a distinct aroma, it seems plausible this is easily covered up by the other characteristics in beer such that it’s imperceptible. As far as the impact on lautering, I’ve certainly experienced the benefit when using mash methods that rely on sparging, but the only thing I noticed on these BIAB batches is that the rice hulls seemed to absorb a bit more wort.

As someone who uses a stainless filtration basket for full-volume mashing rather than sparging, I’ve really no need for rice hulls. That said, I appreciate having data to backup commonly accepted claims, which I feel is what this xBmt yielded. For those who do fly or batch sparge and may have wondered what impact rice hulls have on flavor, these findings suggest it’s nil, so carry on with confidence.

If you have any thoughts about this xBmt, please do not hesitate to share in the comments section below!

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