When Chan Mei Zhi Alcine chose her senior project, she thought outside the box by thinking inside the bottle. Along with a research team at her university, she found a way to combine health and enjoyment, while meeting a challenge not so definitively met before in alcoholic beverages. She and a research team at her university claim they've created the world's first probiotic sour beer.
Probiotics are microbes meant to create a healthy gut microbiome; they are an extra dose of bacteria that naturally live in the digestive system and help it function.
Chan, a fourth-year student at the National University of Singapore (NUS), has been a lifelong probiotic lover — drinking a dairy-based probiotic beverage daily, she told NUS News. While fermented foods and beverages (like beers) are made with microbes and can often be sources of beneficial bacteria, beer presents a unique challenge. The acidity of the hops used to flavor beer can inhibit bacteria, making it difficult for live probiotics to flourish. Researchers changed the brewing process to give the bacteria an advantage and let the probiotic bacteria produce their own, more hospitable acid.
The research team grew both the lactobacillus bacteria and the yeast for the beer in pure cultures so that there was already a good population of probiotic bacteria before those bacteria had to deal with acidic stresses of the other ingredients. They also changed the brewing and fermentation processes for this beer. Unlike other beers, this beer gets its sharp taste from lactic acid produced by the lactobacillus bacteria. The bacteria feed off of sugars in the wort, which is water combined with mashed grain before fermentation.
The team spent nine months experimenting with different strategies to end up with the best probiotic beer they could. The beer they created has a 3.5% alcohol content. It also has at least 1 billion probiotic colony-forming units per serving, to meet the standards set by the International Scientific Association for Probiotics and Prebiotics in their probiotics guidelines of 100 million–10 billion colony-forming units per serving. The beer has around the same amount as some probiotic yogurt.
While beer brewing typically involves microbes, in the form of yeast and sometimes even lactobacillus bacteria, the average beer you get at the store or the pub isn't verified to have live and probiotic cultures. Most commercial beer is filtered and doesn't have any, and the rest (unfiltered beers that you'd order from a specialty brewery) usually just have yeast. And while it's not the first to involve lactobacillus bacteria, other beers aren't made for the survival of the bacteria themselves. The lactic acid they produce creates a sour taste before fermenting, and then the rest of the process goes as usual, and it becomes less than ideal for live bacteria. This beer builds on the probiotic potential that was already there in brewing and might make it a commercial reality.
Chan and Associate Professor Liu Shao Quan (who supervised the research team) say they are interested in working with members of the beer industry to make the probiotic beer commercially available. Chan will graduate in May with a Bachelors of Applied Science with Honours from NUS' Food Science and Technology program; it looks like while the beer she made is sour, her future as a scientist will probably be the opposite.