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Gluten Free Home Brewing Blog

Updated Brewing Recommendations

By GFHB  -  November 21st, 2017

This past year we have conducted well over a dozen test batches to shore up our knowledge of brewing gluten free beer. Things have changed quickly since we started in 2010 as a facebook page sharing the bits and pieces of information and recipes we acquired. Our goal this year was to unlock and clear up many of the questions GFHBers, including ourselves, still have about brewing gluten free beer. 

Brew In A Bag (BIAB): We have really enjoyed using the BIAB method this past year. As it turns out, the BIAB method was the ideal brewing method for filling in some of the gaps in information about gluten free malts and brewing. We used the BIAB method to ascertain the grain absorption rate and grain to hull ratio of rice malt. Conventionally, the BIAB method combines the total grain bill with the strike water to produce the mash. The calculations need to be precise because when you pull the bag of grain out of the kettle, the target preboil volume is left behind. We conducted a series of BIAB test batches which we wrote about on our blog. We have been getting more requests for information about gluten free brewing using the BIAB method. But we need to experiment with this brewing method more before we can make any specific recommendations. 

Enzymes: We are currently conducting a series of test batches using different amounts of different enzymes and will report our findings on our blog; and update our brewing recommendations as appropriate. Remember, gluten free malts have little to no natural enzymes activity; and require the addition of enzymes to the mash in order to turn starch into sugar for the yeast to convert into alcohol. No enzymes = No sugar = No alcohol! Our preliminary findings suggest more enzymes than what we have been recommending may be beneficial. Additionally, longer mash times also appear to be beneficial. 

Grain Absorption Rate: The amount of water grain absorbs can be easily compensated when brewing using the partial mash or all-grain brewing methods because you can simply add the amount of water needed to achieve the target preboil volume. However, the grain absorption rate is crucial when using the BIAB brewing method. At this time, we have ascertained the grain absorption rate of rice malt only, which is approximately 20%. We believe most of the absorption rate of rice malt is actually conducted by the hulls which rice malt has a high percentage of. We intend to conduct a new series of test batches to confirm our theory and also determine the grain absorption rate of millet and buckwheat. 

Grain To Hull Ratio: All gluten free grains contain a hull. However, the hull of millet and buckwheat is very minimal as compared to rice. Hulls provide circulation during the mash and filtration during lautering. Millet and buckwheat require the addition of 10-15% rice hulls to the grain bill to ensure proper circulation and filtration. Rice malt on the other hand has a surplus of hulls. Rice malt contains approximately 62.5% grain to 37.5% hull. You can use this ratio information to calculate how much hull you are obtaining from rice malt in your grain bill; and deduct that amount from the rice hulls you would otherwise need to add to millet and buckwheat malt. 

Partial Mash: Conventionally, partial mash brewing consists of steeping a small amount of malt in water for a short period of time before adding an extract to create your wort. We recently conducted a series of test batches using the Brew In A Bag (BIAB) brewing method and think it could be a great addition to the partial mash brewing method. In theory, by conducting a mini BIAB mash you will convert the starch in the malt into sugar, and allow the malts more of an opportunity to impart flavor while also increasing maltiness and mouthiness. This method would fully utilize the malts giving you the most bang for your buck; and reduce the amount of sorghum syrup required since you would actually get some fermentable sugar from the malts! We look forward to experimenting with this approach in the near future. 

Water To Grain Ratio: We have been recommending a ratio of 1 quart water to 1 pound grain for the last several years. We conducted a series of test batches and stand by that recommendation for the time being. Our results showed a ‘thin’ mash (more water used with the grain bill) resulted in lower conversion. We also experimented with increasing the amount of enzymes used in a ‘thin’ mash. The additional enzymes did increase conversion, but still came short of the conversion using a ‘thick’ mash. Ultimately, a ‘thick’ mash and an increased amount of enzymes resulted in the highest conversion. We are currently conducting a series of test batches using different water to grain ratios and will report our findings on our blog; and update our brewing recommendations as appropriate. 

Yeast Nutrient: We recommend you use ½ tsp yeast nutrient per gallon to ensure active fermentation for all gluten free beers regardless of brewing method. Previously we believed yeast nutrient was necessary for extract and partial mash brewing only. We intend to conduct a new series of test batches to validate our observations; but at this time we are making this recommendation based on our observations of fermentation activity when using and not using yeast nutrient. 

Please follow our progress on our blog and tutorials for updated brewing recommendations!

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