In today’s competitive environment breweries need to produce high quality alcoholic beverages in a time-efficient and cost-effective manner. This has led the use of modern technologies such as high-gravity brewing. However, the benefits of this approach are limited by the ethanol sensitivity of the S. cerevisiae strains. The current study identifies mechanisms contributing to ethanol tolerance in a commercial brewing strain ‘IND1’. This was achieved by creating an ethanol tolerant mutant of the strain and investigating differences between the parent and the mutant in their response to ethanol at a molecular level. Genes contributing to ethanol tolerance were identified and characterised by comparing gene expression profiles of the parent and mutant in the absence and presence of ethanol, using microarray analysis.