Pre-fermentation of malt whisky wort using Lactobacillus plantarum and its influence on new-make spirit character.

Distillery fermentations are non-sterile, which allow bacterial communities to flourish, typically towards the end of fermentation. The effect of beginning the bacterial fermentation at the start of fermentation was investigated. Wort was treated for 48 h using a commercial strain of Lactobacillus plantarum followed by fermentation using a distilling strain of Saccharomyces cerevisiae. The treated wash showed a substantial increase in lactic, acetic and succinic acids Sensory analysis determined that the spirit produced with bacterial treatment were significantly different (p < 0.05) and chemical analysis demonstrated an increase in the production of ethyl acetate. These results show that pre-treatment using species of Lactobacillus could be utilised to alter the quality of new-make spirit in a distillery. By using bacterial cultures present in the surroundings or raw materials, distillers could allow naturally occurring or commercially available microflora to be added thus enhancing flavour development during fermentation and producing different spirit characters.

Uncertainty in Widmark calculations: ABV variation in packaged versions of the most popular beers in the UK.

Forensic practitioners regularly use the Widmark equation to determine theoretical blood alcohol concentrations for use in cases involving alcohol. It is important with these calculations to determine the uncertainty associated with any result. Previous work has investigated the uncertainty in percent alcohol by volume (%ABV) from beers produced by small independent breweries in the UK but did not study the top selling beers in the UK. The top selling lagers and ales/bitters in the UK were identified by sales volume and the %ABV determined. These data was then used to determine the percent coefficient of variation (%CV) that should be used by forensic practitioners when constructing alcohol technical defence reports for use in forensic cases. These samples, from what may be described as 'big' brewers, were determined to have a smaller root mean square error (RMSE) (±0.1%v/v, n = 35), and %CV than those previously reported for beers produced by small, independent breweries in the UK. The results from this study shows that different RMSE's should be used for %ABV when determining the uncertainty of results from Widmark calculations depending if the drinks consumed have been from either 'big' brewers or small, independent breweries.

The influence of alcohol content variation in UK packaged beers on the uncertainty of calculations using the Widmark equation.

It is common for forensic practitioners to calculate an individual's likely blood alcohol concentration following the consumption of alcoholic beverage(s) for legal purposes, such as in driving under the influence (DUI) cases. It is important in these cases to be able to give the uncertainty of measurement on any calculated result, for this reason uncertainty data for the variables used for any calculation are required. In order to determine the uncertainty associated with the alcohol concentration of beer in the UK the alcohol concentration (%v/v) of 218 packaged beers (112 with an alcohol concentration of ≤5.5%v/v and 106 with an alcohol concentration of >5.5%v/v) were tested using an industry standard near infra-red (NIR) analyser. The range of labelled beer alcohol by volume (ABV's) tested was 3.4%v/v - 14%v/v. The beers were obtained from a range of outlets throughout the UK over a period of 12 months. The root mean square error (RMSE) was found to be ±0.43%v/v (beers with declared %ABV of ≤5.5%v/v) and ±0.53%v/v (beers with declared %ABV of >5.5%v/v) the RMSE for all beers was ±0.48%v/v. The standard deviation from the declared %ABV is larger than those previously utilised for uncertainty calculations and illustrates the importance of appropriate experimental data for use in the determination of uncertainty in forensic calculations.