Author Topic: Water in yeast plates?  (Read 1727 times)

boulderbrewer

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Water in yeast plates?
« on: November 23, 2009, 08:42:52 PM »
Can water in yeast plates (after they are pressure cooked) cause problems, such as yeast showing up where you have not streaked yeast or a crystalization on the edges of the plate?

Online Kaiser

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Re: Water in yeast plates?
« Reply #1 on: November 23, 2009, 11:17:03 PM »
Yes, the water can cause the problems you mentioned. I think the water in my plates evaporates slowly through the masking tape I'm using to seal them. After a few days of storage the condensation that was in them is gone.

Kai

boulderbrewer

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Re: Water in yeast plates?
« Reply #2 on: November 24, 2009, 12:20:16 AM »
Kai,

How do you store your plates upside down? Do you seal them (in a ziploc) or do you just use tape to keep the two pieces together? Just trying to get a grasp on this. Is the cystalization bad if you have not opened the plate?  Can the yeast migrate on the liquid an can you have a viable colony away from the streak.

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Re: Water in yeast plates?
« Reply #3 on: November 24, 2009, 06:09:05 AM »
I thought I had a picture of this on-line but I don't.

I use one strip of masking tape to hold the two plates together and then another strip that I tape around the bottom edge such that about 2/3 of its width stand over. I then fold that into the center which "seals" the plate. The plates are stores a plastic shoe box where they'll keep for a few month.

I don't use plates for long term storage though. Just to isolate cultures that I then streak onto a slant and/or stab in agar to make a stab culture. Plates get to easily infected due to the large exposed area when I open them.

Kai

Offline roffenburger

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Re: Water in yeast plates?
« Reply #4 on: November 24, 2009, 08:47:25 AM »
Can water in yeast plates (after they are pressure cooked) cause problems, such as yeast showing up where you have not streaked yeast or a crystalization on the edges of the plate?

I don't see the condensation causing a problem unless its excessive. How much condensation are we talking about? You shouldn't have a puddle. If the condensation gets on the media after you streak, it can swirl around in the plate and "run." Its not a big deal. Store your plates media side up for a day or two and the condensation will evaporate some and be absorbed by the media some. This is the proper way to store (storage and incubation) plates as it prevents them from drying.  You can also open your plates, and dump the condensation (if its really bad), holding the plate in a manner that minimizes the chance of contamination--hold the media so that it faces down. Its not really necessary to tape them shut unless storing them for a while, though it won't hurt and it might be a good idea if you're clumsy ;). I would personally store in a bag instead of taping shut.

Just keep in mind that the kitchen is not a clean place. Use good aseptic technique and you'll be fine.
Travis R.

boulderbrewer

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Re: Water in yeast plates?
« Reply #5 on: November 25, 2009, 09:07:34 AM »
Thanks for the info, guys. The yeasts are now on slants.


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Re: Water in yeast plates?
« Reply #6 on: November 25, 2009, 09:27:49 AM »
Nice. once thing, that makes me more comfortable is taping around the cap. This way nothing gets under the cap and closer to the opening of the vial. Not that it can get into the closed vial but I like to keep the other bugs away as much as it is reasonable.

I also made a log-book for yeast in which I can record how I have been propagating a particular strain. Here is a PDF: http://www.braukaiser.com/documents/logbook_yeast_bank.pdf. I just started using this form but have been keeping track of my cultures ever since I started yeast banking. Some are now as old as 3 years. This is the time since I cultured them first and not the age of a prticular culture. I found that stab cultures make a nice longer term storage than slants while with slants I can easily scrape off some "lawn" and start propagating from that. As a result I now keep one stab and one slant for each yeast strain I have.

BTW, one of the Weissbier bottle dregs I brought back from Germany is finally showing yeast growth. I now have to propagate enough to make a small sample fermentation with it.

Kai

boulderbrewer

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Re: Water in yeast plates?
« Reply #7 on: November 25, 2009, 09:33:44 AM »
Do you use a loop or needle to inoculate your stabs? With visible yeast on the one you use? Thanks for posting the log book.

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Re: Water in yeast plates?
« Reply #8 on: November 25, 2009, 09:47:04 AM »
Some are now as old as 3 years.

What exactly does that mean?  I've just started doing slants (from the info on your web page thank you very much) and I put the date I started each one on it.  When I need to grow up a starter, I use the loop to pull a little off the lawn and go from there.  How long can I keep "mowing the lawn"?  Surely not three years, right?  Do I need to periodically replant a lawn on a new slant?  How often? Best method?
Joe

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Re: Water in yeast plates?
« Reply #9 on: November 25, 2009, 11:42:23 AM »
Do you use a loop or needle to inoculate your stabs? With visible yeast on the one you use? Thanks for posting the log book.

to make a stab, let the agar set w/o resting the vial at an angle. Then take a sterilized needle and stick it into one of the colonies on the plate. After than just stab it a few times into the agar and let the culture grow a little before putting it into the frigde. I don’t think it matters much if you have visible yeast on the needle. I usually have a little bit.

 
Some are now as old as 3 years.

That means I have been able to keep the culture going for 3+ years. That involves periodical re-culturing. I stop harvesting the lawn once it starts looking brown. That usually happens after 4-7 months. At that point I may inoculate a new slant from the old one, get some yeast from a stab culture or start a plate culture from which I inoculate a new slant.

My oldest yeast is a culture of WY2206 and sometime in the future I want to brew a side-by-side with that yeast and a fresh yeast pack from Wyeast. I’m curious if I can detect taste and or fermentation performance differences.

Kai


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Re: Water in yeast plates?
« Reply #10 on: November 27, 2009, 08:41:29 AM »
Quote
My oldest yeast is a culture of WY2206 and sometime in the future I want to brew a side-by-side with that yeast and a fresh yeast pack from Wyeast. I’m curious if I can detect taste and or fermentation performance differences.

Kai

Do you have plans to split a batch and try this out?! Thats good info. I would also be curious how yeast differ once they are several generation off the original culture, espicially going through several brews:

Wyeast pack into A
yeast from "A" into "B"
yeast from "B" into "C"
and so on...

Then  split some wort and pitch the original culture and the yeast from the last brew.

Travis R.

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Re: Water in yeast plates?
« Reply #11 on: November 28, 2009, 07:48:27 PM »
I've been working off plates quite a bit and agree they are much easier to contaminate than slants.  I'm in the process of getting all of my cultures onto slants.  I've never done any stab cultures but I like the idea of doubling up the cultures with one slant and one stab.

When you make new slants to replace an old slant do you steak it out on a plate to check for contamination or do you just innoculate the new slant (or stab) from the old culture directly?

Thanks for posting the yeast culture log, I've been needing something like that! ;D

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Re: Water in yeast plates?
« Reply #12 on: November 28, 2009, 09:09:30 PM »
If the culture is old, I tend to steak them out to isolate a single cell growth. But oftentimes I just skip that step.

Kai

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Re: Water in yeast plates?
« Reply #13 on: November 29, 2009, 03:10:09 PM »
Thanks,

I need to get my but in gear and make up some new slants to transfer some cultures to