Yeastcalc.com (Now two stir plate options?)

[Hermit]

Just my uneducated opinion using both these methods. I think the Troester are always high, and Jamil's are usually within 5-10%. It seems like Troester would be correct in perfect world scenario, in theory, but not reality.

I'm pretty sure Kai's numbers are based on his own research. His methods are published and documented. Can you point me to Jamil's research and his explanation on how he arrived at his numbers?

 

[jwalker1140]

Can you point me to Jamil's research and his explanation on how he arrived at his numbers?

Check out the Brew Strong podcasts on starters and washing. I know he talks about it there, in addition to plenty of other Brewing Network podcast episodes. I've heard him say multiple times that he counted the cells himself from his own beers and I also remember a conversation he had with Chris White where they discussed the research they each did.

Sure, we all stand on the shoulders of others to some degree, but I don't have any reason to doubt that he personally recorded the data points that were fed into the Mr. Malty calculator.

 

[theveganbrewer]

I'm pretty sure Kai's numbers are based on his own research. His methods are published and documented. Can you point me to Jamil's research and his explanation on how he arrived at his numbers?

Aren't they in his yeast book? I haven't read it in a while but I thought there was some talk on this topic in the book.

 

[Hermit]

Aren't they in his yeast book? I haven't read it in a while but I thought there was some talk on this topic in the book.

There is some but the book is Chris White "with" Jamil Zainasheff so I always took that to mean it was basically CW with JZ playing the role of a ghost writer.

 

[maida7]

well they both can't be right... Can they?

 

[simonbones]

How vigorously do you stir the yeast? I've been wondering about this one for awhile now. Once I get krausen on my starter I wonder if I really get anymore oxygenation going on. My plate throws the bar at high speeds so I just get the 'dimple'. Do people pulling vortexes prevent krausen and get oxygenation throughout the process and therefore get more division?

I've wondered the same thing. My Black Maxx can get an awesome vortex that can diffuse air bubbles through the starter. But sometimes I'll get a krausen and other times I won't. When I do, it can go bananas and want to foam out of the top. I can't help but wonder if getting a high krausen foaming up will block the O2 exposure and give a lower growth rate. Perhaps I should start experimenting with giving a pure O2 burst first?

 

[kwadric]

The variation could be in the details that we don't know: yeast strain, temp, yeast health, nutrient, type of stir plate etc.

Sorry if this is off topic:
I'm concerned about the difference in the viability calculator. My HBS has a lot of yeast in the second half of its life span and the difference in yeast viability is significant. I read the work by Woodland and Kai, and I think both made starters from stored yeast... and that might be different from vials or smack packs. Idk.