# Yeast Slants



## Spartan 117 (12/8/09)

Hey Guy's

Been reading on the net on how to make yast slants. I understand the whole preperation process but am unsure about what to do then. Do the slants (like bacterium cultures) need be incubated at a certain temperature and when I have collonies of yeast do I just keep them in the fridge? If so for how long should they be incubated and how long will they keep in the fridge?

Cheers 

Aaron


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## Thirsty Boy (12/8/09)

you incubate them at a nice moderate room temperature for a few days - you will see the yeast growing on the surface of the gel. I like to give my slants a week or so at room temp, so that if there is anything apart from yeast growing on there, I will have a better chance of seeing it. This may or may not be good practice from a yeast viability point...

Then store in the fridge at 4C

I was reading in a recent brewing industry mag (Brewer and Distiller I think) that with the exception of -80 cryogenic storage, slanting and storage at 4C (with reculturing every six months) was the best way to maintain yeast cultures in good, stable condition with a minimum of drift in the fermentation properties of the yeast.

TB


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## ~MikE (12/8/09)

oooh yeah -80C freezer.

yeast slants should be fine for a week at room temp. you can tell when cell viability is dropping off as the yeast itself slowly turns brown from it's nice pasty white as cells die off.


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## Spartan 117 (12/8/09)

Cool, exactly what I nedded to know. Seems like a nice way to save money, growing your own yeasties.

Aaron


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## gwozniak (12/8/09)

Do you guys use that agar stuff as the medium or do you use something else?


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## Spartan 117 (12/8/09)

gwozniak said:


> Do you guys use that agar stuff as the medium or do you use something else?



I'll be usig agar, but only because I'll be getting it free from Uni  , I'll also try to get my hands on some test tubes if they'll let me.....

Aaron


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## buttersd70 (12/8/09)

Some use geletin, some (if not most) use agar. One of the main complaints (from others, that I've read in other threads) with geletin is that it doesn't set firm enough. I use agar.

Personally, when I make a bunch of blanks, I keep them for several days at room temp before I innoculate them, just to be absolutely sure that they're OK. My first batch I had 2 duds that started growing stuff....


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## ~MikE (12/8/09)

don't use gelatine, just don't unless you absolutely cannot get agar.


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## gwozniak (12/8/09)

So where do you get agar from?


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## altone (12/8/09)

gwozniak said:


> So where do you get agar from?



Your local asian supplies store.


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## Spartan 117 (12/8/09)

gwozniak said:


> So where do you get agar from?




Asian grocers usualy by what the internet says. and if you cant get it there im sure someone here will know of a source. 

Aaron


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## gwozniak (12/8/09)

Hahaha,
And here i was thinking i'm gonna have to make contact with a bio weapons lab


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## gava (12/8/09)

I use gelatine and all my slants work fine... 



~MikE said:


> don't use gelatine, just don't unless you absolutely cannot get agar.


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## samhighley (13/8/09)

Gelatine is not as stable as agar at warmer temperatures, which makes it a pain in the arse if you live in warmer climates.

Agar will remain solid until very warm temperatures (60C+) while gelatine starts to turn back to liquid at temperatures around 30C.

Go with agar if you can find it. I get it at the local asian grocers. It's the same as the one listed on the Beerbelly page.


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## gava (13/8/09)

Ah, that would be a pain in hotter places..I have a temp controlled area for growing the yeast then i keep mine in a fridge. no real risk of turning back into liquid.

Is Agar more expensive than Gelatine? 



Sammy said:


> Gelatine is not as stable as agar at warmer temperatures, which makes it a pain in the arse if you live in warmer climates.
> 
> Agar will remain solid until very warm temperatures (60C+) while gelatine starts to turn back to liquid at temperatures around 30C.
> 
> Go with agar if you can find it. I get it at the local asian grocers. It's the same as the one listed on the Beerbelly page.


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## raven19 (13/8/09)

FWIW, I use Gelantine, and use it in a 50/50 mix with malt... made up to around 1040. This seems to set quite well at room temps.

My first slants did not have enough gelatine in them, hence melted a bit.


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## ~MikE (13/8/09)

gava said:


> Ah, that would be a pain in hotter places..I have a temp controlled area for growing the yeast then i keep mine in a fridge. no real risk of turning back into liquid.
> 
> Is Agar more expensive than Gelatine?



not really, i get 42g pack for $2 - is enough for just over 2L of media.

gelatine melts if the slants get warm. yeast love growing at 30C, gelatine loves melting around that temp . agar sets at room temp, no need to put it in the fridge, you can leave it at room temp for weeks and it'll be fine, unlike gelatine. if your culture (this shouldn't be the case with yeast though) produces proteases then it will dissolve the gelatine and leave you with liquid. there's quite a few reasons not to use gelatine, but if you have to, it will work.


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## samhighley (15/8/09)

Melting slants is a royal PITA. Go for agar. It's cheap and readily available.


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## Bribie G (15/8/09)

Not too lazy to do a search, just while this thread is live at the moment where do you guys source your test tubes and what $$$ ? What's the best type of tube, plastic or lab quality glass? Do they have pop on or screw on lids? If pop on then do you seal them by dipping them say in melted candle wax like some winemakers with their corks??

Why so many questions two dogs? :icon_cheers:


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## pdilley (15/8/09)

BribieG said:


> Not too lazy to do a search, just while this thread is live at the moment where do you guys source your test tubes and what $$$ ? What's the best type of tube, plastic or lab quality glass? Do they have pop on or screw on lids? If pop on then do you seal them by dipping them say in melted candle wax like some winemakers with their corks??
> 
> Why so many questions two dogs? :icon_cheers:



Plastic or Glass. Glass is what I have used in the past and glass is what the yeast meisters at the club use.
I have not bookmarked any web sites but there are a few good laboratory and medical supply mail order firms out there, others will probably chime in.

Wort and Agar are cheap so most people don't get bothered with the waste of surface area by buying large capacity tubes and just filling them up. That said, you only use the increased surface area created by turning the tube on its side to set the agar at an angle and not the 3/4 of a giant tube of wort poured beneath it. You work on the surface with Agar, not through the substrate -- for that we have specialty gels for 3-dimensional work.

Tube holder frames are cheap, plastic jobs you snap together yourself. The only problem is most are not slant holders so you have to prop them at an angle until the agar sets. Another option is to get tubes with sides that extend down to the bottom past the dimple or cone and can set upright on their own. Because surface area is all you want you can also look at anything wide and squat and forget about slanting them - something closer to the petri dish which is what you really want anyway for surface area, which is why they were invented and used, just that most glass petris do not have screw on lids.

Most of this is sold at a price per lot of items. Expect anywhere from $20 and up for a set of tubes with screw on caps. Qty depends on what its made from and what size (you can also use some Cetrifuge Vials as tubes as well as some have good seals. Plastic frames are $10-20 range.

I'm going to see about getting my borosilicate petri plates and sample vials brought over from the states as I have a huge collection just sitting around in storage 


EDIT: If you have a pressure cooker already then you are set. You can do sterilisation lab techniques (steam + pressure is the most effective per cost) as well as santisation techniques (just boiled on stovetop at standard atmospheric pressure)

Cheers,
Brewer Pete


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## RdeVjun (15/8/09)

BribieG said:


> Not too lazy to do a search, just while this thread is live at the moment where do you guys source your test tubes and what $ ? What's the best type of tube, plastic or lab quality glass? Do they have pop on or screw on lids? If pop on then do you seal them by dipping them say in melted candle wax like some winemakers with their corks??
> 
> Why so many questions two dogs? :icon_cheers:


I got my first batch of about a dozen for free from the skip at work! Thankfully they were empty and intact, cleaned them myself of course and then filled with agar/wort and sterilized. But, in the long term, I'll be needing some more too, which brings me to my question- do many folks use Falken tubes or centrifuge tubes for slants?




(Source: Proscitech)
I just happen to have some handy plus a couple of racks, would make the whole slanting caper a bit easier if I don't have to go and buy some others. The ones on the left are free- standing which is neat, but we have the racks anyway.

Oh, BribieG, the glass ones I sent you guys were just stand- ins that I had at the time, again from the magic skip at work. The lid is a bit suss for mine, but I just happened to have about the right number handy to propagate some more from the original/ master slants. 
BTW- again, many thanks for those Mike! Actually, the ones he sent me were similar to those in the photo above, so I know at least one person does use them, just wondering if there's many others.

Also, thanks Pete, have just seen your post, I might just give the plastic tubes we already have a go. I also got some glass dishes from the magic skip, jeez I had a yeast field day when I spotted that it was full of useful goodies they were (so wastefully-) tossing out from the pathology & entomology labs!


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## ~MikE (15/8/09)

BribieG said:


> Not too lazy to do a search, just while this thread is live at the moment where do you guys source your test tubes and what $$$ ? What's the best type of tube, plastic or lab quality glass? Do they have pop on or screw on lids? If pop on then do you seal them by dipping them say in melted candle wax like some winemakers with their corks??
> 
> Why so many questions two dogs? :icon_cheers:



a lot of people get their stuff from here. http://www.proscitech.com.au/cataloguex/online.asp?page=l9 - but any lab supplier should stock them.

either the 50ml centrifuge tubes or the 30ml sample tubes work well, they come sterile, and are polypropylene, so can be autoclaved/boiled for re-use without losing their shape or integrity. plus they're cheap 

edit:
beaten


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## Sammus (15/8/09)

yeah those vee bottom containers about 1/3 the way down were standard for all here a while ago, many a bulk buy happening. Well, ones that looked like it anyway, they were discontinued recently, and those ones and the ones under it look very similar. I got the PP version of the vee bottom which isn't listed anymore, id probably get PC if I did it over again.


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## altone (15/8/09)

~MikE said:


> a lot of people get their stuff from here. http://www.proscitech.com.au/cataloguex/online.asp?page=l9 - but any lab supplier should stock them.
> 
> either the 50ml centrifuge tubes or the 30ml sample tubes work well, they come sterile, and are polypropylene, so can be autoclaved/boiled for re-use without losing their shape or integrity. plus they're cheap
> 
> ...



So even the caps on those things survive autoclave/pressure cooker temps ok?
(I differentiate betwen autoclave and your average pressure cooker, as mine only runs at 8psi - so lower temp)
If they do I'll get some when I run out of my sterilized 1 shot tubes.

confirm if you can, 
Ta


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## ~MikE (15/8/09)

boddingtons best said:


> So even the caps on those things survive autoclave/pressure cooker temps ok?
> (I differentiate betwen autoclave and your average pressure cooker, as mine only runs at 8psi - so lower temp)
> If they do I'll get some when I run out of my sterilized 1 shot tubes.
> 
> ...



the centrifuge tubes, 30ml sample tubes and i'm guessing their lids as well are polypropylene (they'd say if they weren't), and the vee bottom tubes are polycarbonate with polypropylene lids, all are autoclavable. http://www.proscitech.com.au/cataloguex/plastics.asp


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## altone (15/8/09)

~MikE said:


> the centrifuge tubes, 30ml sample tubes and i'm guessing their lids as well are polypropylene (they'd say if they weren't), and the vee bottom tubes are polycarbonate with polypropylene lids, all are autoclavable. http://www.proscitech.com.au/cataloguex/plastics.asp




Thanks for that, I don't trust generic specs as one lot of lids I purchased recently are meant to be polypropylene but they change shape after a trip through my pressure cooker (it's only an 8psi job).
I'm using them as one shots because of this.

Just wanted to confirm with someone who'd actually autoclaved them that they work fine.

Cheers


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## Sammus (16/8/09)

I haven't used an autoclave but in cook PP in my pressure cooker at 16psi all the time, once for 2 hours, never had a problem.


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## RdeVjun (16/8/09)

Sounds perfect, many thanks chaps! Pretty soon I'll be giving the tubes and lids I have on hand a whirl in the cooker with some agar & wort. :icon_cheers: 

Oh yeah, WRT melting caps, there's specs and then there's specs. I seldom trust manufacturers or suppliers as far as I can kick them, be it lab consumables, kit, sensors etc, they're often just a pack of thieving liars and we've learnt to test some ourselves before placing big orders. For instance, we bought around a hundred 500kg strain gauges for a large array of field sensing, but I bought a few before that and tested them thoroughly to be sure they'd be up to spec. Sure enough they were, but because they were a good bit cheaper than competing products I had serious doubts. Being surprised like that doesn't happen very often, but its far better than the unpleasant surprises later on when we find that the supplier was pulling our leg/FoS. There's more to it than just performance though, longevity and integration with existing systems are important too but I'm getting way, way, way OT... sorry...


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## pdilley (16/8/09)

I have 3 pressure cookers in storage in the states, they all went up to 25 PSI, built like nuclear reactors with thick walls and tie downs.

Google All American Pressure Cooker Canner to see photos 

Are the pressure cookers you guys have the stove top one that looks like a saucepan with a slide locking top? I have one of those as well over there but never got to use it before moving back here.

EDIT: Nevermind, found photos of them:





Cheers,
Brewer Pete


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## ~MikE (16/8/09)

boddingtons best said:


> Thanks for that, I don't trust generic specs as one lot of lids I purchased recently are meant to be polypropylene but they change shape after a trip through my pressure cooker (it's only an 8psi job).
> I'm using them as one shots because of this.
> 
> Just wanted to confirm with someone who'd actually autoclaved them that they work fine.
> ...



i think it'd be more of a temperature thing than pressure, i dunno how temp control is having never used a pressure cooker before.


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## pdilley (16/8/09)

Mike,


With pressure cookers, the pressure and temperature go hand in hand. Steam sterilisation requires atmospheres of pressure to aid the heat penetration.

Its overkill for most beer brewers but Its from my past when I used to run the mycology lab at the mushroom farm. :icon_offtopic: When I'm all kitted out and in full gear in all my brewing endeavors I might fire up my mycology lab in my house and pump out some fresh gourmet mushrooms. God knows its hot enough during summer here in Canberra but the dry climate is the killer. I'll have to assemble a humidity controlled grow room. Fresh Paddy Straw mushrooms, injected with tamari soy when still in egg form and baked in the oven for a flavour explosion when eaten, YUM!

Making mould for sake production will probably get me off my arse and down the road to kitting out my home lab again.

Cheers,
Brewer Pete


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