Changes

The esters that were analyzed were ethyl acetate (pineapple, pear, solventy), ethyl butyrate (tropical fruit), ethyl hexanoate (apple), ethyl decanoate (apple, brandy), ethyl octanoate (waxy, pineapple), isoamyl acetate (banana), isobutyl alcohol (solventy), and isoamyl alcohol (fusel, banana). Ethyl acetate had the most sporadic results. It was highest in the 100% BSI-565 fermentation (43 ppm; above the 33 ppm odor threshold), and lowest in the 100% BSI-Drei fermentation (21 ppm; below the 33 ppm odor threshold). The different , but when co-fermentation fermented the ethyl acetate production rates formed a pattern of more ethyl acetate as the pitching rate of BSI-Drei 565 was increased, but they were still lower than decreased and the 100% pitching rate of BSI-565 fermentationDrei was increased. The 75/25 ratio produced 27 ppmof ethyl acetate, 50/50 produced 34 ppm, and the 25/75 produced 42 ppm (BSI-565 to BSI-Drei ratio in percent pitching rate). Ethyl butyrate was The highest in ethyl acetate concentrations were therefore for the 100% BSI-565, and curved downward as the pitching rate for the BSI-565 strain was decreased. Ethyl butyrate was below odor threshold in the 10025% BSI-Drei fermentation. This indicates that the production of ethyl butyrate was dependent on the pitching rate of BSI-565, and that the BSI-Drei strain did not produce significant amounts of this ester. For each of the esters ethyl hexanoate, ethyl decanoate, ethyl octanoate, they had a slight decrease as the pitching rate of BSI-565 decreased, indicating that these esters are produced more by the BSI-565 strain, however the small measured differences may not be reflected in the actual taste/aroma of the beers since the differences were so small. The exception was ethyl decanoate which was around 3x higher in the 10075% BSI-Drei, which indicates that ethyl decanoate is a major flavor contributor to 100% BSI-Drei fermentations. Overall, the ester concentrations were significantly lower in the BSI-565/BSI-Drei fermentations compared to the strains of ''S. cerevisiae'' and ''B. bruxellensis'' used by [[Brettanomyces_secondary_fermentation_experiment|Lance Shaner and Richard Preiss in their similar experiment]], indicating that total ester concentrations are highly dependent on the strains used. Isoamyl acetate, which was above odor threshold in the 100% BSI-565 fermentation, was almost not detectable in any of the fermentations that contained BSI-Drei (it was 0 ppm in the 100% BSI-Drei fermentation), which is in agreement with other studies that ''Brettanomyces'' hydrolyzes this ester. The alcohols isobutyl alcohol and isoamyl alcohol were slightly decreased as the pitching rate of BSI-565 decreased, and were extremely low in the 100% BSI-Drei, indicating that these alcohols were produced more so by BSI-565.

Ethyl butyrate was highest in the 100% BSI-565, and curved downward as the pitching rate for the BSI-565 strain was decreased. Ethyl butyrate was below the odor threshold in the 100% BSI-Drei fermentation. This indicates that the production of ethyl butyrate was dependent on the pitching rate of BSI-565, and that the BSI-Drei strain did not produce significant amounts of this ester. For each of the esters ethyl hexanoate, ethyl decanoate, ethyl octanoate, they had a slight decrease as the pitching rate of BSI-565 decreased, indicating that these esters are produced more by the BSI-565 strain; however, the small measured differences may not be reflected in the actual taste/aroma of the beers since the differences were so small. The exception was ethyl decanoate which was around 3x higher in the 100% BSI-Drei, which indicates that ethyl decanoate is a major flavor contributor to 100% BSI-Drei fermentations. Overall, the ester concentrations were significantly lower in the BSI-565/BSI-Drei fermentations compared to the strains of ''S. cerevisiae'' and ''B. bruxellensis'' used by [[Brettanomyces_secondary_fermentation_experiment|Lance Shaner and Richard Preiss in their similar experiment]], indicating that total ester concentrations are highly dependent on the strains used. Isoamyl acetate, which was above odor threshold in the 100% BSI-565 fermentation, was almost not detectable in any of the fermentations that contained BSI-Drei (it was 0 ppm in the 100% BSI-Drei fermentation), which is in agreement with other studies that ''Brettanomyces'' hydrolyzes this ester. The alcohols isobutyl alcohol and isoamyl alcohol were slightly decreased as the pitching rate of BSI-565 decreased, and were extremely low in the 100% BSI-Drei, indicating that these alcohols were produced more so by BSI-565. The phenols that were measured in Mader's experiment were 4-vinylguaiacol (clove), 4-ethylguaiacol (smokey, spicy), and 4-ethylphenol (medicinal, barnyard). While the 100% BSI-565 fermentation had high levels of 4-VG (1800 ppm), they were less than half the amount in the co-fermented ferments (600-800 ppm) but still above odor threshold (300 ppm) (the different ratios of BSI-565 to BSI-Drei did not have a large impact), and 4-VG was below threshold in the 100% BSI-Drei fermentation. 4-EG and 4-EP had high levels in the co-fermentations with BSI-565 and BSI-Drei and the 100% BSI-Drei, and the ratios did not have a large impact. This is in agreement with another experiment by [[Brettanomyces_secondary_fermentation_experiment|Lance Shaner and Richard Preiss]] that showed that pitching rate of ''Brettanomyces'' after fermentation with ''S. cerevisiae'' did not have a great affect effect on the levels of phenols produced <ref>[https://www.facebook.com/groups/MilkTheFunk/permalink/1935201276508077/ Nick Mader. 2017 Master Brewers Conference Presentation. 2017.]</ref>.