Homebrewing and portable NIR instruments: monitoring the fermentation of readymade malt extract using the SCiO sensor

What do miniaturized NIR spectrometers and homebrewing have in common? From a conceptual point of view, the do it yourself motto. Let’s break this claim down. New miniaturized spectroscopic instruments are launched on the market to try to satisfy the need of both researchers and consumers for quick ways for analysing stuff, especially in the food field: these small instruments are frequently operated via smartphone apps, which also often include pre-trained models to quantify specific properties (e.g., fat or protein content). The user can therefore, to different extents, use the instruments to perform measurements and rather easily build her/his own calibration models. Homebrewing has become a very widespread hobby, with a wide range of equipment available on the market, allowing people to simply ferment readymade malt extracts, but also to brew more complex recipes. Standard recipes provided by the malt producers are generally “optimized”: few actions must be taken, and few parameters must be controlled to obtain a fairly decent beer. In this study, we investigated the overlap between these two conceputally-connected worlds. The fermentation of a commercial readymade malt extract was followed for 14 days by means of NIR spectroscopy, using the portable handheld SCiO sensor (Consumer Physics) equipped with its accessory for liquid measurements. A small amount of brewing liquid was taken once a day from the fermentation tank, and 30 spectra were acquired with the SCiO instrument. The exploratory analysis done by Principal Component Analysis (PCA) revealed interesting trends that could be related to the evolution in time of the homebrewing process and to the recorded temperature of the brewing liquid, both of which can be related to the different stages of maturation of the beer during production.