Making yeast slants?

[johnmac]

Should I buy test tubes, or vials? Glass or plastic? If test tubes, what about bungs/lids? What size is best? Best to buy on ebay, or not?

I gather cooking agar is just as good as lab standard agar? Or do some people use gelatin?

For a flame, will it be OK to use the gas hob or do I need an alcohol lamp?

Any advice gratefully received...

[Eadweard]

"Universals" is what you're after. Glass or platic is fine, but plastic ones are single use.

[Wolfy]

Glass test tubes can be easily sterilized and reused, but if you don't plan to reuse them, plastic is probably cheaper and easier to work with.

Agar purchased from a (Asian) supermarket is fine to use (and is my preference), but some people use gelatin without problem. You'll be boiling to sterilize your agar (or gelatin) and wort mixture, so as long as it solidifies when it cools that's what matters most (I find that agar tends to work better with my procedures).

A flame serves two useful purposes; the first is to flame/sterilize the inoculation loop used to transfer the yeast and streak the surface, the second is to create an 'updraft' via convection, hence keeping any dust or other potentially contaminating particles from falling onto the surface you are working with. You may or may not be able to do that with your gas hob, however an alcohol lamp is small, easy and portable - a bunsen burner, hand held propane torch, or any similar clean source of flame can be used equally well.

[mitch]

Should I buy test tubes, or vials? Glass or plastic?

Glass (autoclavable) culture bottles, 30-40mL.

Best to buy on ebay, or not?

The Ebay seller baffcat has some 28mL autoclavable culture bottles.

I gather cooking agar is just as good as lab standard agar? Or do some people use gelatin?

Agar Agar from a health-food shop or Chinese supermarket works well. Gelatin will loose the ability to set after being properly heat sterilized. Available from Ebay seller geordie256 (100g of Agar Agar will make about 5L of wort-agar, enough to prepare about 600 slopes).

For a flame, will it be OK to use the gas hob or do I need an alcohol lamp?

Gas hob is a bit too low, alcohol lamps are not very powerful and also quite low. Get a cheap camping stove (the kind that screw onto the top of a small gas canister).

Don't forget your inoculation loop. Get some 24 swg NiChrome wire (Ebay), clamp a 2mm drill bit in a vice, fold a section of your wire in half, clamp the ends of the wire in the chuck of a hand-drill, loop the wire over the shank of the clamped drill bit and twist away. Baffcat sells loop handles but you can use a craft knife handle.

[Scooby]

I also use a small camping gas stove and these Autoclavable tubes from baffcat, being polypropylene they can be used in a pressure cooker.

I got this Agar Agar, should last a while as I use 1.5g in 100ml

[Waffty]

I use the same 28ml culture bottles, mitch listed, Agar Agar powder and NiChrome wire, Baffcat, sells a holder, just grab the end with a pair of round nose pliers and made a loop.

I then use an Advant baby bottle steriliser to keep everything sterile. Works well.

As a tip, make enough Wort to make your slops and also keep some 'neat' wort for your first starter i.e I usually make 5 Agar slopes + 5x 28ml wort starters.

[Fuse]

Personally i prefer using THESE however they come in a massive box and ive not seen lower quantites split down etc on something like eBay - they come pre-sterilised so all you have to do is pour in your agar and away you go, i used to use Universal tubes as recommended earlier but have has problems in the past with them so dont really use them now. I also just use dispsable innoculation loops rather than having to sterilise and flame loops all the time, you can get them on eBay from the guy mentioned above HERE. For short term storage i tend to use YPD agar slopes (i.e. 3-6 months, essentialy the same as Wort agar) but was reccomended to use duck egg agar slopes for longer term storage (1-2years), but i usualy just restreak cultures more regularly.

I also dont bother using a flame or anything as it really doesnt make a huge amount of difference as long as you are working in a reasonably clean area thats not been dusted in a few days its fine, i tend to do it in the kitchen.

[Scooby]

As a tip, make enough Wort to make your slops and also keep some 'neat' wort for your first starter i.e I usually make 5 Agar slopes + 5x 28ml wort starters.

I collect a few litres of wort at the start of a brew and pressure cook for 15mins in kilner jars or small baby feed pots for the initial starter. These can be stored anywhere that's dark and will keep for ages, just pop them as needed for starters.



I always use spray malt for the slopes as it's such a small amount and easy to do, then pressure cook the wort/agar in the tubes for 15mins, leaving them in the cooker allowing the pressure to drop slowly. That way you know the whole lot are completely sterile.

I also dont bother using a flame or anything as it really doesnt make a huge amount of difference as long as you are working in a reasonably clean area thats not been dusted in a few days its fine, i tend to do it in the kitchen.

I reckon it's best to use a flame of some sort and keep as close to it as possible when opening vials and inoculating.

[johnmac]

Thanks very much. How long will a slant last? I think the stock answer is 'a year' but I'm hoping they last a lot longer, in practice?

[Scooby]

Brewlab say use within 6 months. I believe Aleman has successfully propagated from Brewlab slants over 1 year old.

I guess it depends how strict a regime you follow, I have some I made 8months ago that still have a creamy white look,
and some that look like peanut butter, supposedly a bad sign.

[Wolfy]

Thanks very much. How long will a slant last? I think the stock answer is 'a year' but I'm hoping they last a lot longer, in practice?

A year is a good estimate, and it does not hurt to reculture and reslant your yeast on an annual basis - at least you know it is viable that way.

But in theory the slant will last as long as the yeast remains viable, and that depends on how/where you store it as well as the procedures used to create the slant and also to reculture the yeast for your starter.
Someone here on the forums said they've been using the same (commercially purchased) slant to reculture yeast for the last 4 years!

[johnmac]

I've got everything ready to go, except I can't find our old pressure cooker. Would an unpressurised boil do instead?

[floydmeddler]

Have just finished preparing my slants and they are 'setting' now. Will inoculate two tomorrow - one with Duvel yeast that I have in a 100ml starter at the minute and the other will be WLP005 which is in the fridge... well what's left of it! Only need a tiny bit anyway. Pretty excited. Even made me a little record sheet.

Plan is to finally start collecting yeast from pubs. Was worried in the past about nasties but now I'll be able to pick out healthy colonies... I think! Still learning!

[Scooby]

Have just finished preparing my slants and they are 'setting' now. Will inoculate two tomorrow -

I leave my newly made slants in a warm place for about 3 days just to be sure they are 'clean'.

[Wolfy]

Plan is to finally start collecting yeast from pubs. Was worried in the past about nasties but now I'll be able to pick out healthy colonies... I think! Still learning!

Streaking onto petri-dishes would be best for that - as long as the yeast you are collecting is a single strain type.