Yeast Culturing Equipment

[Thirsty Boy]

to ask a couple of stupid questions..

you dip the loop into the yeast pack while it is still red hot? I assume it's a liquid yeast pack?

Yes, liquid culture. No need to slant a dried culture, they are already in a stable storable form.

 

[Amber Fluid]

Yes, liquid culture. No need to slant a dried culture, they are already in a stable storable form.

Trying not to state the obvious here but I'm going to, why doesn't the hot loop kill the yeast it collects?
I am assuming that it cools on contact with the liquid, but still kills off a few cells although too little amount to worry about.

 

[therook]

Trying not to state the obvious here but I'm going to, why doesn't the hot loop kill the yeast it collects?
I am assuming that it cools on contact with the liquid, but still kills off a few cells although too little amount to worry about.

Spot On

 

[Wolfy]

Trying not to state the obvious here but I'm going to, why doesn't the hot loop kill the yeast it collects?
I am assuming that it cools on contact with the liquid, but still kills off a few cells although too little amount to worry about.

Yes, that's the theory - the loop is so small/thin that it cools virtually instantly.
However, I've had a few yeast-culturing attempts fail because I did not cool the loop well enough.

 

[piraterum]

Yes, that's the theory - the loop is so small/thin that it cools virtually instantly.
However, I've had a few yeast-culturing attempts fail because I did not cool the loop well enough.

Simple solution get some disposable (sterile) 1uL or 10uL Inoculation Loops. They are cheap to buy and a box will last you a lifetime :beerbang:

Available from plenty of Laboratory / Scientific suppliers like e.g. Livingstone International http://www.livingstone.com.au/

No affils etc etc plenty of suppliers to choose from

 

[Wolfy]

Simple solution get some disposable (sterile) 1uL or 10uL Inoculation Loops. They are cheap to buy and a box will last you a lifetime :beerbang:

The problem with the disposable ones is they can't be heat sterilized and so are really single-use-only (and if I used them for each slant I make, that's about 300 a year).

 

[piraterum]

The problem with the disposable ones is they can't be heat sterilized and so are really single-use-only (and if I used them for each slant I make, that's about 300 a year).

They come in boxes of 1000 so that should last you a while :icon_cheers:

Not to mention save a lot of f**king about with a wire loop, which have a much higher contam risk than using a gamma sterilised disposable one

 

[Wolfy]

Not to mention save a lot of f**king about with a wire loop, which have a much higher contam risk than using a gamma sterilised disposable one

There is a bit of messing around with a wire loop, however I don't think much of anything can survive the loop being heated to red/white-hot ... can it?

 

[benno1973]

Simple solution get some disposable (sterile) 1uL or 10uL Inoculation Loops. They are cheap to buy and a box will last you a lifetime :beerbang:

Similar theory, I use sterile syringe needles. Cheap to buy a box of them and lots of brewing uses. I just suck a little into the syringe and squirt that into the slants/testubes.

 

[MaltyHops]

Yes, that's the theory - the loop is so small/thin that it cools virtually instantly.
However, I've had a few yeast-culturing attempts fail because I did not cool the loop well enough.

Another simple solution is to keep a vial of vodka to dip the hot loop into to cool it (assuming there's no chance of the vodka blowing up - hmmm must test this sometime :huh: ).

 

[troopa]

Is 40% vodka enough to sterilise or does it need to be higher in alc% ?

 

[MaltyHops]

Is 40% vodka enough to sterilise or does it need to be higher in alc% ?

This homebrewtalk poster writes "You need 80% concentration of
alcohol for 45 seconds to sanitize. Your cheap vodka is likely 40%
alcohol (80 proof) and way too low a concentration for sanitizing
unless you have very, very long contact times (but it's not going
to grow stuff on its own or harm already-sanitized stuff, so it's
okay for filling airlocks and such)."

There's also brewingtechniques article

 

[Wolfy]

Is 40% vodka enough to sterilise or does it need to be higher in alc% ?

Isopropol (rubbing) alcohol (comes in a green bottle with a crocodile on the front) is what I use, it's 80% and probably cheaper than vodka (also use it for a clean heat-source for our fondue).

 

[Lord Raja Goomba I]

Similar theory, I use sterile syringe needles. Cheap to buy a box of them and lots of brewing uses. I just suck a little into the syringe and squirt that into the slants/testubes.

Free with a diabetic in the house.

Goomba

 

[Darkman]

Isopropol (rubbing) alcohol (comes in a green bottle with a crocodile on the front) is what I use, it's 80% and probably cheaper than vodka (also use it for a clean heat-source for our fondue).

Wouldn't Metho be just as effective?

 

[piraterum]

There is a bit of messing around with a wire loop, however I don't think much of anything can survive the loop being heated to red/white-hot ... can it?

Some environmental mould spores are resistant to dry heat and alcohol. The other thing to consider is the rest of the loop is not being heated so there is potential for contamination from the handle.

Metho is fine to use for flaming e.g. dipping a loop in metho and flaming it. If you are using alcohol to sanitise a 70% ethanol solution is the most effective concentration. Using higher concentrations (80%, 100%) is less effective. There are plenty of peer reviewed papers demonstrating this.

 

[kieran]

This homebrewtalk poster writes "You need 80% concentration of
alcohol for 45 seconds to sanitize. Your cheap vodka is likely 40%
alcohol (80 proof) and way too low a concentration for sanitizing
unless you have very, very long contact times (but it's not going
to grow stuff on its own or harm already-sanitized stuff, so it's
okay for filling airlocks and such)."

There's also brewingtechniques article

While the 40% vodka is too low, sterilising in 80% (by volume) alcohol for 45 seconds is complete overkill (like using an H-bomb to kill a mouse) and a waste of time.
A 1 second double-dip/shake and flame is more than enough to kill even the most pervasive bacteria and yeast. As for spores, if you're worried, before the first dip flame the loop until it is glowing. Then let it cool, dip and flame. That technique has served me well for over 10 years in the lab, with controls, and perfect bug growing environments (so any contamination had a great chance of kicking-off).

Methylated spirits is denatured alcohol, and it's cheap. It's also usually available in 4L jugs at Bunnings. Dilute that to ~80% by volume (which works out to about 70% by weight), and a quick dip and flame and you're done.
Of course, pure alcohol is the best, but for a back yard homebrew environment, "metho" is just fine.


side note.. has anyone with access to it, used ampicillin/kanamycin/choramphenicol on home plates to kill off any bacteria? Not sure how easy it is to get in the home for regular brewers though. Ampicillin is pretty well controlled now, as an S2 drug so that probably won't fly, but I don't think the others are?

 

[manticle]

(like using an H-bomb to kill a mouse)

Fucker won't ever piss in my pantry again though will he?

 

[MaltyHops]

.
Methylated spirits is denatured alcohol, and it's cheap. It's also usually
available in 4L jugs at Bunnings. Dilute that to ~80% by volume (which
works out to about 70% by weight), and a quick dip and flame and
you're done.
Of course, pure alcohol is the best, but for a back yard homebrew
environment, "metho" is just fine....

I'd always been put off by the "POISON" printed on bottles of metho
and since using for yeast cuturing would end up in the beer we drink
- or would the amount ending up in the beer be so low as to be
negligible?

Pure alcohol is also not easy to get.

 

[manticle]

Flaming will drive that tiny amount away. Many a kitchen I used to work in would rinse clean cutlery in hot water and a touch of metho.