We used liquid chromatography-mass spectrometry (LC-MS) to identify and quantify hordatines and amino acids in sour beer samples collected over the course of a year. To make sour beer, brewers extract sugars from grain and use yeast and bacteria to ferment the extract.  Brewers age the resulting beer in barrels for months to years, and many compounds such as hordatines and amino acids that can affect flavor and mouth feel change in concentration during the aging process.  Hordatines are phenolic compounds that are produced in barley and result in a sour flavor after extraction and aging. Amino acids are the result of metabolic processes carried out by the yeast and bacteria during fermentation. While there are many studies on regular beer and a few studies on beers related to sour beer, most of those studies focused on finished products and very few have explored sour beer itself. We collaborated with Sour Cellars brewery in Southern California to obtain samples of beer taken from the same barrel over several months and across multiple batches of beer. We used LC-MS to confirm the presence of different types of hordatines and amino acids in each sample, and to quantify the concentrations of the compounds.  We used the results to identify trends in levels of hordatines and amino acids as a function of time and batch. Understanding how concentrations of compounds such as amino acids and hordatines can fluctuate can help brewers in terms of quality-control, reproducibility and being able to better predict flavors in the end-product.

Analysis of hordatines and amino acids in sour beer using liquid chromatography-mass spectrometry

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.