Homemade water kefir: Characterisation and first evidence of an effect on breath alcohol testing

Abstract

varying levels of ethanol, and the impact of its consumption on the breathalyser is still unknown. Since manycountries have established regulations on the levels of alcohol permitted in drivers, this study aimed to assess theeffect of water kefir intake on the results of breath alcohol tests. Water kefir was prepared under four differentconditions: 4 % and 6 % (w/v) brown sugar, with or without 10 % (v/v) lemon juice. Chemical analysis (pH,organic acids, ethanol and saccharose) and microbiological counts (lactic acid bacteria, acetic acid bacteria, andyeasts and moulds) were performed at the beginning and after 24 and 48 h of fermentation. The condition thatresulted in the highest ethanol production was used to produce water kefir for a breath alcohol test. Finally, twoassays were conducted: 16 and 12 adult individuals drank 150 mL and 300 mL, respectively, of water kefir, andthe concentration of breath alcohol was quantified using a breathalyser. The water kefir used had a pH value of3.30 and a level of 2.17 ± 0.08 g/100 mL of ethanol. In the first breath alcohol test, 16 participants were offered150 mL of water kefir. None of them resulted positive to the breath alcohol test when performed after 30, 60, 90or 120 min from ingestion. In the second assay, 13 participants were offered 300 mL of the same water kefir. Onlyone participant tested negative at all time points assessed. For the rest of the participants, breath alcohol testswere positive from min 10, peaking at min 30, and became negative after 75 min of the intake. Even with ratherlimited data, it is possible to conclude that water kefir intake may render positive a breath alcohol test,depending on the volume and ethanol content of the kefir consumed, as well as on other variables such as theBMI (Body Mass Index) of the consumer.