title: Influence of yeast strain, priming solution and temperature on beer bottle conditioning.
abstract: BACKGROUND
  Recently, there has been a significant increase in the number of microbreweries. Usually, craft beers are bottle conditioned; however, few studies have investigated beer refermentation. One of the objectives of this study was to evaluate the impacts of different experimental conditions, specifically yeast strain, priming solution and temperature, on the standard quality attributes, the volatile compounds and the sensory profile of the bottle-conditioned beer. The other aim was to monitor the evolution of volatile compounds and amino acids consumption throughout the refermentation process to check if it is possible to reduce the time necessary for bottle conditioning.
  
  
  RESULTS
  The results indicate that the volatile profile was mainly influenced by the strain of yeast, and this may have obscured the possible impacts of the other parameters. Our results also confirm that the two yeast strains showed different metabolic activity, particularly with respect to esters production. Moreover, we found the Safbrew S-33® strain when primed with Siromix® and refermented at 30 °C yielded the fastest formation of higher alcohols while maintaining low production of off-flavours.
  
  
  CONCLUSIONS
  These results suggest a formulation that may reduce the time needed for bottle conditioning without affecting the quality of the final beer which may simultaneously improve efficiency and economic profits. © 2016 Society of Chemical Industry.
authors.affiliation: Department of Agricultural, Food and Environmental Sciences, University of Perugia, Via S. Costanzo, n.c.n, 06126, Perugia, Italy.
authors.forename: Ombretta
authors.initials: O
authors.lastname: Marconi
authors.affiliation: Department of Agricultural, Food and Environmental Sciences, University of Perugia, Via S. Costanzo, n.c.n, 06126, Perugia, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Rossi
authors.affiliation: School of Agricultural, Forestry, Food and Environmental Sciences, University of Basilicata, Via dell'Ateneo Lucano, 10, 85100, Potenza, Italy.
authors.forename: Fernanda
authors.initials: F
authors.lastname: Galgano
authors.affiliation: Italian Brewing Research Center, University of Perugia, Via S. Costanzo n.c.n., 06126, Perugia, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Sileoni
authors.affiliation: Italian Brewing Research Center, University of Perugia, Via S. Costanzo n.c.n., 06126, Perugia, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Perretti
mesh_terms: D000328:Adult; D000368:Aged; D001515:Beer / Q000382:microbiology*; D000431:Ethanol; D005260:Female; D005285:Fermentation; D005516:Food Microbiology; D063427:Food Quality; D006801:Humans; D008297:Male; D008875:Middle Aged; D012441:Saccharomyces cerevisiae / Q000145:classification*; D013649:Taste; D013696:Temperature; D055815:Young Adult
chemical_list: D000431:Ethanol
keywords: beer; bottle conditioning; volatile profile; yeast