kidnextdoorz
New Member
- Joined
- Sep 24, 2016
- Messages
- 3
- Reaction score
- 1
Hi fellows
I have been making yeast starter for a while and decide to get serious about counting yest cell after the propergation to gauge a propoer pitching rate this also include viability test as well.
At first trial my initial cell count is 160 billion cell of yeast in total with 74% vability and this a washed harvested imperial A07 yeast. I propagated the yeast in 1.5 ml of 1.040 SG malt extract wort and let it spin on stir plate for 36 hours at 22 degC then start to assess the total number of cell. With a big hope of getting a large number of cells from this starter as calculated by a starter calculator I only get about 190 billion cell of yeast in total with 84% viability.
In a subsequence propagation I still face the same yeast cell growth scenario, way too low growth from what the calculator said e.g. initial cell count of 70 billion cell, did a 2 step starters 1.5 l and then 3.5 l of 1.036 SG wort and the final cell count was 270 billion cells.
I am using a dilution factor of 1:20 (dilute 1 ml of yeast sample to 9 ml of water and then bring 1 ml of this mixture to mix with 1 ml of 0.1 % methylene blue solution) and count the yeast in all 25 squares of hemocytomerter. I am not sure that is it my yeast counting practice or there are something wrong about my yeast propergation. Any suggestions?
I have been making yeast starter for a while and decide to get serious about counting yest cell after the propergation to gauge a propoer pitching rate this also include viability test as well.
At first trial my initial cell count is 160 billion cell of yeast in total with 74% vability and this a washed harvested imperial A07 yeast. I propagated the yeast in 1.5 ml of 1.040 SG malt extract wort and let it spin on stir plate for 36 hours at 22 degC then start to assess the total number of cell. With a big hope of getting a large number of cells from this starter as calculated by a starter calculator I only get about 190 billion cell of yeast in total with 84% viability.
In a subsequence propagation I still face the same yeast cell growth scenario, way too low growth from what the calculator said e.g. initial cell count of 70 billion cell, did a 2 step starters 1.5 l and then 3.5 l of 1.036 SG wort and the final cell count was 270 billion cells.
I am using a dilution factor of 1:20 (dilute 1 ml of yeast sample to 9 ml of water and then bring 1 ml of this mixture to mix with 1 ml of 0.1 % methylene blue solution) and count the yeast in all 25 squares of hemocytomerter. I am not sure that is it my yeast counting practice or there are something wrong about my yeast propergation. Any suggestions?
