Culturing Yeast

Drifter · 01-28-2009, 02:22 PM

I have successfully created slants and grew the colonies and pitched them. Here's my question I made 6 slants from an original WYeast slap -pack. Now I am down to one slant, what is the proper way to make more slants with this last slant.

**conpewter** · 01-28-2009, 04:12 PM

I freeze my yeast instead of using slants, but what I do when I am down to my last culture is to make a starter with it (being extra careful about sanitation) and then I'll use that starter to freeze more yeast. Since I don't use much yeast out of the starter I can then pitch it into wort if I need, otherwise it just goes to waste.

fratermus · 01-29-2009, 03:10 PM

Quote:

Originally Posted by Drifter

I have successfully created slants and grew the colonies and pitched them. Here's my question I made 6 slants from an original WYeast slap -pack. Now I am down to one slant, what is the proper way to make more slants with this last slant.

Make more slants, and use your noc loop to inoculate the new slants from the old. As always, use your sterile-as-possible technique, flaming/quenching, etc.

Purists might suggest that you plate out the culture from the last slant into a petri dish first, grow that, then inoculate the new slants. This might be indicated if you are concerned about the health or purity of that last culture. I've had good success both ways.

I just recultured a slant that was 8mos old and it took off fine on the plate.

**raceskier** · 01-29-2009, 06:01 PM

I would add one more point. That is when you are culturing from a slant, there is no need (if you keep things sterile) to discard the slant. I use a 10 ml first step propogation and just a noc loop (pinhead size) volume of yeast stolen from the slant is adequate. At this consumption rate, one slant will be adequate for many propogations.

I have a nice 1318 London Ale starter from this method happily spinning and churning away on the stirplate right now.

I make multiple slants of the same yeast, just to have backup spares on hand. (anal retentive engineer who works satellite reliability here)

fratermus · 01-30-2009, 12:07 PM

Race, how are you handling that first 10ml step? I've tried a few different methods and all seem to work, but wanted to get feedback on best practices:

* smaller volume like 5ml in a culture tube, still

* 10ml in a 50ml flask, still

* 10ml in a 50ml flas, my smallest stirbar thrashing around in the shallow pool