The article deals with brewing beer with a higher degree of wort fermentation using Brettanomyces yeast added during second bottle fermentation. Its оorganoleptic properties are analyzed. Malt bill composition is 65% of Pilsen light malt, 20% of Vienna malt and 5% of caramel malt. 10% of inverted sugar syrup is added at boiling stage. Infusion mashing is made with mash ratio of 1:4. Fermentation is carried out at 25 ±1 deg C. The effects of top-fermentation Belgian Ale Yeast - Mangrove Jacks and Belle Saison strains on fermentation process and the quality of finished beer are analyzed. M-27 and M-79 Mangrove Jacks strains are shown to have the highest degree of fermentation during main fermentation, being 97.2 and 97.8%, respectively. Fermentation of beer with Brettanomyces bruxellensis yeast is carried out for 60 days at 20 deg C. In samples with Brettanomyces bruxellensis yeast being added at the maturation stage the degree of fermentation is improved highly (99.7%). Increased color degree (8 SRM) and active acidity (рН 4.0-3.8) are also exhibited in the samples. Organoleptic properties evaluation is carried out using 25-grade scale. The beer with M-27 Mangrove Jacks yeast used for main fermentation gets the maximum number of points (23): 5 points for taste, 5 for bitterness, 5 for flavor, 4 for opacity and 4 for color. The least balanced in taste and flavor is the beer made using M-79 Mangrove Jacks yeast: 2 points for taste, 4 for bitterness, 2 for flavor, 4 for opacity and 4 for color.