The Complexities of Non-alcoholic Beers - Understanding How Production Methods Shape Fresh Flavor and Aging Profiles

Non-alcoholic beers (NABs) are experiencing significant growth in production and consumer demand, yet their chemical properties, flavor profiles, and aging behaviors are still underexplored. This study investigates the effects of varying brewing techniques - namely fermentation with maltose-negative yeast, thermal dealcoholization, and combined methods - on the characteristics of NABs. Eight commercially available German Pilsner-style NABs were analyzed for key chemical parameters including alcohol content, original gravity, residual sugar concentration, bitter compounds, polyphenols, and volatile compounds derived from malt, hops, and fermentation. Sensory analysis was conducted alongside chemical assessments, and the effects of storage conditions (4 °C and 20 °C) over 12 months were examined to assess the aging behavior of these NABs.

Cluster analysis (dendrograms) revealed distinct groupings based on both analytical and sensory data, showing that production techniques and brewery origin significantly influenced the chemical and sensory profiles of the NABs. Chemical differences were highly attributed to residual sugar content, which varied depending on the production methods used. Sensory evaluations confirmed noticeable flavor variations, particularly concerning fermentation by-products and aldehydes, with some samples exhibiting prominent wort-like characteristics. Fresh NABs displayed significant chemical variability, predominantly determined by the production method. Alcohol content ranged from below 0.02 % vol in two products labeled as 0.0 % vol to up to 0.40 % vol in others. NABs with higher residual sugar concentrations exhibited sweeter flavor profiles and increased mouthfeel, a direct result of the brewing technique applied. Other parameters, such as pH, color, and bitterness, were consistent with previous findings for non-alcoholic Pilsner-style beers. Polyphenol content ranged from 71 mg/L in the NAB produced with maltose-negative yeast to 264 mg/L in thermally processed products, generally lower than in alcoholic lagers but comparable to other NABs.

Principal component analysis (PCA) identified three main clusters: isotonic beers (with higher sugar content, as required by regulations), combined-method NABs, and thermally processed beers. Isotonic NABs were characterized by higher residual sugars and aldehydic compounds like methional, resulting in more wort-like sensory attributes. Combined-method NABs clustered around aldehyde-related descriptors, which contributed to increased "odor intensity" and potential off-flavor development, while thermally processed beers exhibited more traditional beer characteristics, such as estery and fruity notes.

Aging behavior varied according to production technique, with aged NABs displaying more pronounced sweet, worty, and oxidized characteristics. The study underscores the critical role of both production methods and storage conditions in determining the aging behavior, stability, and sensory quality of NABs. The correlation between aldehyde levels and sensory degradation emphasizes that both storage temperature and production methods are pivotal in shaping the quality and long term acceptability of NABs over time. Statistical analyses offer valuable insights into how these factors contribute to flavor differences and potential aging effects (off-flavors), highlighting the importance of optimizing brewing and storage processes to enhance product stability and quality.