Food scientists show rice malt may play a bigger role in beer

Rice has shown potential to play a more important role in beer brewing, helped by the state’s large production of rice.

About half of the rice in the United States is grown in Arkansas, mostly long-grain rice. Meanwhile, climate change and international conflicts are causing shortages of raw materials traditionally used in beer brewing, particularly barley.

A new study titled “Investigating malting suitability and brewing quality of different rice varieties” was published in February in the journal beverage, suggesting that rice malt can provide powerful fermentation in gluten-free all-malt beers and styles that use a lot of additives. Additives are additional sugar sources for beer fermentation.

Rice and corn have been used as supplementary grains in American breweries since the 1860s. However, the rice is polished white rice and does not use koji. Because the malt quality of U.S. rice varieties had not yet been evaluated for brewing quality, one of the objectives of the study was to identify rice varieties with high malting potential.

Bernardo P. Guimarães, a graduate student in food science, is the lead author of the rice malt study and is the first to publish data analyzing the brewing quality of 19 varieties of malt that are important to the U.S. rice industry. Scott LaFontaine, a flavor chemist and assistant professor in the Department of Food Science, served as Guimarães’ advisor on this research.

“Does rice have what it takes? Scientifically, it is possible,” LaFontaine said.

They discovered that rice malt has enough enzymatic capacity to completely convert starch sources into fermentable sugars (also called autosaccharifying malt). This malt produces a sweet liquid called “wort” during brewing. LaFontaine says wort from rice malt “appears to be able to ferment healthily with standard yeast without the need for added enzymes or nitrogen supplementation.”

Do you have an extra container to put rice koji in?

Malting is the process of germinating grain by hydration and then drying and heating to stop germination. This process produces the enzymes needed to convert starches into sugars when soaked in boiling water during a brewing step called “mashing.” When it comes to rice, brewers have typically used polished white rice rather than rice malt. Using milled white rice requires additional brewing vessels because it needs to be boiled to gelatinize the starch and turn it into a sweet liquid called wort.

On the other hand, with rice malt, you may not need a second container. Guimarães and Lafontaine showed that rice malt undergoes autosaccharification under appropriate brewing conditions. In other words, given the right temperature and time, starch is broken down into fermentable sugars, which yeast can assimilate and turn into alcohol.

Just as wheat flour is to bread, barley malt is to beer, and barley is used in varying degrees as a base malt, along with other grains such as wheat, rye, and oats, to suit different styles of beer. Recipes required. Additional ingredients such as roasted barley or roasted malted barley create different flavors and aromas.

The study showed that malting long-grain rice is the most promising competitor to malted barley in terms of sugar content and other brewing qualities. The study looked at short-, medium-, and long-grain varieties of “paddy rice,” meaning rice with the chaff removed but not the husks. Interestingly, a wild variety of rice with purple bran produced naturally colored gluten-free beer with a wine-like hue.

new discovery

Previous public research on rice malt has been conducted on Italian and Indian varieties, and research on rice malt in the United States yielded two interesting findings, Lafontaine said. First, gelatinization temperatures vary among rice varieties, and mashing parameters appear to influence the onset of gelatinization.

“We don’t yet know exactly what’s going on, but this is likely due to rice malt’s unique enzyme profile, and brewers need to adjust their mashing conditions to effectively utilize this material in their breweries. It shows that all you have to do is change,” LaFontaine said. Gelatinization temperature is lower.

Another unexpected finding was that rice malt exhibited higher protein levels than previously reported, offering potential application as an alternative protein source in food. LaFontaine said. New research has shown that protein content ranges from 7% to 10.5%, with some rice varieties having protein content comparable to malted barley.

Depending on the rice variety being grown, this study could represent a value-added product for farmers whose rice becomes highly whitish during milling. Chalk rice is opaque and tends to crumble during processing, making it less valuable as a food. However, when it is sent to a malt mill to become rice malt, chalk does not affect the quality much. High nighttime temperatures during rice grain development have been shown to cause chalk. LaFontaine noted that as the climate warms, this will be an issue that farmers and scientists will have to continually grapple with.

Economy and flavor

While chemical analysis of rice malt is promising, Lafontaine is working with the Bureau of Agricultural Economics and Agribusiness to conduct a feasibility study that considers a number of economic factors comparing rice malt to barley malt. .

One of the most pressing economic factors is the price of barley, which has increased over the past four years. Mr Lafontaine said the increase had brought long-grain rice prices “on par” with barley. Barley is grown in areas with a cool climate, and rice is grown in areas with a warm climate. Climate change and global warming are therefore another factor in the long-term economic impact of barley and rice as beer ingredients, he added.

“Providing brewers in the South and the United States with more locally grown grains, water rice requires proportionally more carbon dioxide to grow than malted barley, yet lacks international transportation.” could make up for the difference in carbon dioxide,” the study said. “Additionally, rice is also a gluten-free starch source for brewers and beverage and food manufacturers.”

Lafontaine plans to conduct a sensory panel of various beers made from rice malt. For example, he and Guimarães found that some aromatic varieties of rice had higher levels of diacetyl, which has a buttery, popcorn flavor often thought of as an off-flavor in beer.

“As preliminary information for the next part of this study, I would say that the rice varieties had many different and interesting aromas and flavors,” Guimarães said. “We believe it has great potential as a stand-alone ingredient or in combination with malted barley.”

During the study, rice varieties were malted in small quantities using techniques comparable to industry standards. In each small test batch, the researchers measured protein content, enzyme levels, and other characteristics important to brewing. LaFontaine’s lab is licensed and insured as a University Beverage Development Facility with a 15-gallon electric brewing system, providing hands-on experience for students in the University’s Brewing Science Proficiency Certificate Program.