Starting from slants - initial cell count?

[Argyll Gargoyle]

I’m a homebrew noob learning to be a yeast rancher. I followed the instructions on inoculating slants from the sticky thread in this forum - so far so good.
It looks like the usual way to create a starter from said slants is to use the entire slant.

First question: what is a good assumption for initial cell count (per unit area of the slant surface)?
Second question: how do I determine how many steps my starter needs, and the optimal volumes for these steps?

Thanks

 

[TheMadKing]

I’m a homebrew noob learning to be a yeast rancher. I followed the instructions on inoculating slants from the sticky thread in this forum - so far so good.
It looks like the usual way to create a starter from said slants is to use the entire slant.

First question: what is a good assumption for initial cell count (per unit area of the slant surface)?
Second question: how do I determine how many steps my starter needs, and the optimal volumes for these steps?

Thanks

A good rule of thumb is to start with 10mL of wort and never increase the volume by more than a factor of 10 in a single step. So 10mL, 100mL, 1L, 2L is not unreasonable

 

[bracconiere]

https://en.wikipedia.org/wiki/Cell_counting
i've always thought people worried about cell count use a microscope and a kinda graphing thingy......like if you stick under the scope, and see 10-100 or some amount of cells in a mm then you can calculate how many are in the whole culture....

 

[day_trippr]

hemocytometer

But I don't think the OP is looking in that direction, but instead was hoping for a recipe to get from slant to pitch...

Cheers!

 

[bracconiere]

hemocytometer

homebrewing can be as cheap or expensive as a person wants to take it! i just googled it, and here's a cell-o-meter for $2k! never wonder if your starter is ready again

https://shop.nexcelom.com/products/...ETYCrnokBq_TbAdhpWtAGG6VzjWPZizcaAhNFEALw_wcB

 

[day_trippr]

hahaha! Everyone should have one
But...yeast cell size would surely test the optical resolution of that machine, being down in the 5 micron range, which looks like their stated limit...

Cheers!

 

[bracconiere]

I still want my UV-Vis Spectrometer.....that way i could work on my protein purification skills, and make my own gluco!

 

[Argyll Gargoyle]

Thanks for the guidance on starter volumes - the 10x progression seems pretty reasonable.

I might try some cell counts to get a ballpark number for cells in a slant — microscope is on order. Any recommendations on how to approach this? I would probably start some new slants, trying to cover as much of the surface as possible. Might need to experiment with how many days to let them grow, temperature, etc

 

[Vale71]

homebrewing can be as cheap or expensive as a person wants to take it! i just googled it, and here's a cell-o-meter for $2k! never wonder if your starter is ready again

https://shop.nexcelom.com/products/...ETYCrnokBq_TbAdhpWtAGG6VzjWPZizcaAhNFEALw_wcB

Funnily enough those expensive image-based cell counters are less accurate than a trained lab-monkey... I mean technician. But they do save time which is probably more important for a commercial operation. Fluorescence-based cytometry is where it gets really fancy but you'll have to add at least one more zero to the price for some basic gear...

 

[eimar]

It looks like the usual way to create a starter from said slants is to use the entire slant.



Thanks

No need to use the entire slant, get yeast from the slant once using an inoculating loop and inoculate a 10 ml of wort in a test tube . Then successively multiply by 10.