Progress and modelling of cold contact fermentation for alcohol-free beer production: A review

Cold Contact Fermentation (CCF), or Cold Contact Process (CCP), is one of the many methods of producing beer with little to no alcohol content through a combination of low fermentation temperatures and extended fermentation contact times. Although this method was first discovered in 1983, its importance in academic and industrial circles has risen only recently, parallel to the rising demand for Alcohol-Free Beer (AFB) recorded world-wide. For the discussion of this topic, the origins of AFB and the current market perspective of the sales and consumption of Low or Alcohol-Free Beer (L/AFB) serves as an introduction, followed by an exploration of the various methods of producing L/AFB. After these two introductory sections, an in-depth discussion of the biochemical pathways present in fermentation is presented as well as the mathematical basis upon which fermentation modelling stands in the form of Differential-Algebraic Equations (DAE) modelling. Finally, a sequential review of the organoleptic properties of beer and the previously published fermentation system models in literature segues to the critical evaluation of this study. CCF, either with the use of free mass or immobilized yeast, is considered one of the best available production methods for producing AFB given the relatively minor additional capital investment and the ability to meet the various ethanol concentration specifications. However, several issues are discussed, most notably the difficulty reported in attenuating the contributions of negative flavor compounds that are generally reduced to higher degrees during standard fermentation practices. •Cold-Contact Fermentation (CCF) is a process for manufacturing Alcohol-Free Beer (AFB).•Advantages and disadvantages of post-processing methods for ethanol removal are covered.•Biochemical and yeast metabolic pathways towards flavour-contributing compounds are discussed.•Quantitative data for all flavour-contributing compounds are organoleptic properties are tabulated.•Dynamic mathematical models for CCF simulation on the basis of first principles are analysed.