tag:blogger.com,1999:blog-2261525107149934458.post6373801389812709893..comments2023-08-17T06:55:36.859-04:00Comments on Woodland Brewing Research: Starter Cell GrowthAnonymoushttp://www.blogger.com/profile/18109943319735098753noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-2261525107149934458.post-24129824256363362612013-01-21T12:47:00.668-05:002013-01-21T12:47:00.668-05:00I've been keeping a log of my starters as well...I've been keeping a log of my starters as well. Some of them to follow the 10 million per °P per litter. Unfortunately many of my starters are experimental in some way, so I'm not sure that it indicates correlation. Anonymoushttps://www.blogger.com/profile/18109943319735098753noreply@blogger.comtag:blogger.com,1999:blog-2261525107149934458.post-86952134701233034002013-01-21T11:59:35.261-05:002013-01-21T11:59:35.261-05:00Interesting that these were not stirred. I wonder ...Interesting that these were not stirred. I wonder if you saw the high growth b/c dry yeast comes with lots of internal reserves or because the tall beer column caused circulation that was equivalent to stirring. The aspect that dry yeast has more reserves than liquid yeast should only matter foe the higher inoculation rates.<br /><br />Are you also seeing the same growth rate for non stirred regular sized starters?<br /><br />KaiAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-2261525107149934458.post-66132520771773265562013-01-21T11:21:20.128-05:002013-01-21T11:21:20.128-05:00Thanks Kai!
What you are suggesting sounds reason...Thanks Kai!<br /><br />What you are suggesting sounds reasonable. The results I have here are far from conclusive, but hopefully shows a relation between sugar concentration and cell growth. Further experimentation is necessary.<br /><br />The yeast was re-hydrated US-05. Twenty five test tubes were inoculated and allowed to culture at ambient air conditions for about two weeks. There were an additional two higher inoculations that showed unusual results that I could not interpret, so rather than try to explain something that I did not understand I did not report that data thinking that there must have been some error. These may follow what you saw.<br /><br />There are a number of other variables to consider. Two weeks ensured that the cultures with the lowest inoculation rates and highest sugar concentration completed, however the cultures on the other side of the spectrum were sitting at completion, in the alcohol they had produced, for a long period of time.<br /><br />But that's just the tip of the iceberg. It seems every experiment leads to a whole slew of follow up experiments.<br />Anonymoushttps://www.blogger.com/profile/18109943319735098753noreply@blogger.comtag:blogger.com,1999:blog-2261525107149934458.post-20602625024951239332013-01-21T09:46:32.280-05:002013-01-21T09:46:32.280-05:00Thanks for running these experiments Steven. I ver...Thanks for running these experiments Steven. I very much welcome if others are looking into starter yeast growth and don’t blindly trust Jamil’s calculator. <br /><br />Where these still, shaken or stirred starters? It’s not obvious from your write-up, but the numbers seem to align with what I found for stirred starters (http://braukaiser.com/blog/blog/2012/11/03/estimating-yeast-growth/). But there are some differences. When I plotted your data as new billion cells per gram of extract over initial billion cells per gram of extract I noticed that you are getting much more growth at high initial cell densities than I do. My experiments, done with liquid yeast, showed a drop in yeast growth around 1.5 billion initial cells per gram. In your data even with 4 B/g initial cells you were getting ~ 1 billion new cells per gram of extract. I think this is because you were working with dry yeast and I was working with liquid yeast. They both are in different metabolic states when they are put into fresh wort. The dry yeast doesn’t have to replenish reserves before it can start growing which allows it to grow more when there is less extract per yeast cell.<br /><br />Kai<br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-2261525107149934458.post-4811415463634587652013-01-20T09:43:22.945-05:002013-01-20T09:43:22.945-05:00Yes, directly following the pitch the container is...Yes, directly following the pitch the container is shaken until 75% or more of the volume is foam. This should achieve approximately 8ppm of oxygen. After that no further oxygen is introduced.Anonymoushttps://www.blogger.com/profile/18109943319735098753noreply@blogger.comtag:blogger.com,1999:blog-2261525107149934458.post-18760922932698751062013-01-20T02:05:45.253-05:002013-01-20T02:05:45.253-05:00So it looks like you're getting the amount of ...So it looks like you're getting the amount of growth Jamil's calculator predicts with a stir plate, without using a stir plate. Did you aerate the starter at all?Lee Morganhttps://www.blogger.com/profile/00698409525485698378noreply@blogger.com