Originally Posted by tagz
Great thread. I have a question about Woodlands latest blog post. Hope you don't mind me tacking it on here. Woodland discussed an equation showing the number of cells produced as a function of sg and fg. Seeing as most people pull their starters after 24 hours, are we not getting the optimal number of cells out of our starters? I assumed most reproduction occurred during the lag phase, but the numbers seem to indicate that reproduction chugs along until you hit fg.
Also, I've never really measured the sg of my starters. Do most starters hit fg after 24 hours?
It would be good to hear what others think about this as well.
(here is a direct link to the post for anyone interested: http://woodlandbrew.blogspot.com/2013/02/cell-growth-as-function-of.html
This is something I have been investigating and am working on some posts that might help illuminate some of this. In short, it's dependent on a number of factors, but given some constraints you can get a pretty good estimate. For a starter propagated at room temperature with an inoculation rate of about 50 million healthy cells per ml and a gravity of about 10°P (1.040) It takes about 4-6 hours for propagation to begin. In the first 24 hours half of the cells are generated. By 48 hours nearly all of the cells have been generated.
Feel free to comment on the blog with questions directly related to it. I'm normally pretty quick about replying.