General Category > Yeast and Fermentation

Loop vs. needle?

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enso:
So, I just streaked my first plates.  Fun!   ;D

I used my inoculation loop as most sources I have read instruct.

I have an inoculation needle though as well.  In my eagerness to get going I placed an order with more beer and got their overpriced needle.  This was before I learned about cynmar.  So now I have both and I am not sure what the needle is for.

What I have read indicates that the loop is for streaking plates and slants and the needle is for stabs.  I don't understand the purpose of a stab though.  I get that you stab the inoculated needle into the agar in a slant, but what does that do?  How do you then work with this?

Kaiser:
stab cultures tend to remain viable longer since the yeast grows inside the agar where it doesn’t have access to oxygen. I had a few cases of 12+ month old yeast where the slant culture was dead but the stab culture still had live cells which I was able to culture on a plate and then in new slants and stabs.

Kai

enso:
Okay thanks. 

How do you then access this yeast inside the agar to propagate it?

Kaiser:

--- Quote from: enso on February 04, 2010, 10:30:08 AM ---How do you then access this yeast inside the agar to propagate it?

--- End quote ---

stab the needle in it a few times and then streak it over the plate. That's what I do and it seems to work. You don't really have to stab exacly into the hole you made first. There seems to be enough viable yeast throughout the agar.

Kai

Thirsty_Monk:
Thank you for the info.
I also have both loop and needle but so far I used loop only.

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