Are My Slants Ok?

Australia & New Zealand Homebrewing Forum

Help Support Australia & New Zealand Homebrewing Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

braufrau

Autumn Leaf Brewery
Joined
9/12/06
Messages
1,242
Reaction score
2
I've got a bunch of slants in the fridge and they all look like, well, hmm .. something that came out my nose.
A white smear across the agar.
But I made 3056 slants 2 weeks ago and they look more like something that would grow on cheese.
White, but spotty.
Is it OK? I threw away my 3068 slants because they looked that way.
 
I've got a bunch of slants in the fridge and they all look like, well, hmm .. something that came out my nose.
A white smear across the agar.
But I made 3056 slants 2 weeks ago and they look more like something that would grow on cheese.
White, but spotty.
Is it OK? I threw away my 3068 slants because they looked that way.

Any chance of a photo?

Both sound OK (white is good), mine are usually spotty but the different patterns might be due to different innoculation techniques.
 
I've got a bunch of slants in the fridge and they all look like, well, hmm .. something that came out my nose.
A white smear across the agar.
But I made 3056 slants 2 weeks ago and they look more like something that would grow on cheese.
White, but spotty.
Is it OK? I threw away my 3068 slants because they looked that way.


braufrau,

I have only slanted yeasts the once (Prefer to split the wyeast pack into "X" tubes then farm the next 4 or 5 generations) but if the yeast is healthy it should appear as a white film on the surface of the agar. Anything other than the white film is to be avoided as it is not healthy yeast according to my research.

T
 
I've got a bunch of slants in the fridge and they all look like, well, hmm .. something that came out my nose.
A white smear across the agar.

Photos of some healthy yeast growth:

slantgrowth.jpg


From the guide I use for slanting:

http://www.unm.edu/~draper/beer/slantuse.html
 
OK. I sacrificed one for the purposes of illustration. doesn't look so bad now. :)

slant.gif
 
They look ok to me, most of mine look pretty similar.
As mentioned above depending on innocculation technique they will not always look like someone elses.
 
Braufrau, there is nothing wrong with the slant. Thats just yeast.
 
Hey Braufrau,

The slopes look fine :super:

I used to be a manager of a commericial yeast culture collection and found excess moisture in the agar caused alot of slopes to go all runny which is evident in your pics. Excess water of the surface of the agar runs down the slope while the yeast is growing, making the colonies fuse together resulting in a large white film.

The solution is to leave the slopes to dry once the agar is set. Ie leave them for 24hrs with the lids loosly on.

Innoculating the slopes also takes a bit of practice. The best way to get nice individual colonies is to start at the bottom of the slope and move the loop in a circular motion as you streak side to side working towards the top of the slope. Don't go right to the end of the agar - leave a little bit near the top to avoid contamination.
It's best to use sterile innoculation loops which you can buy easily online e.g. http://www.livingstone.com.au/item_info_po...;item_id=173220

The caps of the slopes should be sealed with a strip of sterile parafin film to prevent contamination - particuarly by moulds
http://www.livingstone.com.au/item_info_po...;item_id=190071

Store the slopes in the fridge they should keep for 6 months. Any longer than this the agar starts to dry out and depleted of nutrients which leads to unhealthy yeast.

cheers,

piraterum
 
Sorry to hijack, but I just wanted to know Piraterum if you have any advice on storing yeast longer. A glycerol stock in the freezer perhaps?
 
Thanks everyone. I'm such a worry wort! :)

I just started some coopers yeast, in its slanty tube, and the wort I'd pressure cooked was in a glass jar and when I went to pour it into the slant, the damn bottom fell out of the jar! Now I have a big (bigger) mess to clean up in the kitchen!
 
I had a weird yeast slant the other day its london esb ale wy1968 Im guessing its just gas escaping as I have pushed the loop too deep into the medium.

Check it out

YEAST_SLANT.JPG

looks gross but I used 1 so far and no worries with it.

:icon_cheers:
 
Sorry to hijack, but I just wanted to know Piraterum if you have any advice on storing yeast longer. A glycerol stock in the freezer perhaps?


Hey Mad Hopper,

You can store yeast cultures in the freezer by mixing glycerol broth culture with 100% glycerol and freezing it. However, labs use -80 deg freezers. I'm not sure how stable they would be in a -10 deg domestic freezer.

If you're interested here is a freezing method:

Medium: Glycerol Broth


Ingredients per litre
Sucrose 10g
Vegetable Peptone Broth 15g - can use animal based peptone, this is a kosher recipe.
Phytone Peptone 5g
K.H2PO4 1.75g
Glycerol 40g



Preparation
1. Dissolve all ingredients in water.

2. Dispense 100ml into 200ml conical flasks.

3. Autoclave at 121C for 15 minutes.


Q.C. Tests
A. pH 5.9 0.2

B. Appearance Tan broth

C. Sterility 30C 3 days O2



The procedure for freezing cultures is as follows:

1. Single colony taken from slope and inoculated to Glycerol Broth
2. Incubated at 30C for 1 day = yeast culture
3. 2ml of 100% glycerol is added to 10ml of yeast culture.
4. 1.8ml quantities are divided into cryotubes.
5. Cryotubes put into -80C freezer.
 
Thanks for that, I might give it a shot. I work in a biology lab and we store bacteria as glycerol stocks at -20C if we can't be bothered putting them in a -80C or liquid nitrogen freezer (or if we need frequent access). Never worked with yeast though and for our purposes we don't really care if the stock retains strain characteristics as we just use them for vector production.

I'll see how this goes in a standard -10C/-20C freezer over time and let people know how it turns out.

Alternatively I could label a box at work "dangerous, do not open" and hide some stocks in there! :D
 
Back
Top