4/30/09 – Thursday
Over the past month or so I have been e-mailing with Greg Doss of Wyeast Labs as previously mentioned and it turns out the gracious people over at Wyeast were able to supply the Brettanomyces Masters Project with three slopes. WY5112 (B. bruxellensis), WY5526 (B. lambicus) and WY5151 (B. claussenii) were shipped over from the USA and have arrived safely. This brings the strain count up to eight different strains that are being used in the research!
The slopes were looped and inoculated into 6 sets of 250 ml conical flasks containing 100 ml of solution for propagating up to pitchable amounts. I will be observing the growth during batch culture in two different mediums this time. Of the six flasks the strains were inoculated into, three contain MYPG solution and three contain wort solution. This is a quick observation to test the difference in growth between the two mediums. Conditions are the same as with all the batch culture propagations: Temperatures of 28°C in the Orbital incubator with agitation around 80 rpm, semi aerobic conditions with foam bung in the conical flask tops and aluminum foil covering.
5/6/09 – Wednesday
What I observed was interesting. I found a slightly higher amount of non-viable cells in all three of the MYPG solution flasks as the over all viability was 96.68%, while after 6 days the cells grown in wort solution had 99.73% viability overall. As for cell growth a different pattern was observed. For B. bruxellensis the wort/mypg cell ratio average per square on the hemocytometer was 228.4/104, for B. lambicus 125.2/76.8 and for B. claussenii 117/134.2. This shows that the yeast have different growth behaviors based on the composition of the media. This could be important in choosing the right wort to use for a 100% Brettanomyces fermentation, or when propagating up cells for pitching into a primary or secondary fermentation. The flasks were then added to 500 ml of sterilized wort solution. As they are grown up into pitchable amounts I will take daily cells counts monitoring the cell growth to see if the initial media continues to have an effect or not. All propagation data from the eight strains will be put into graphs and made available as soon as I get the last of the data.