Equipment Questions

[Clinton]

I have recently acquired an ex-lab Erlenmeyer flask for making yeast starters. Apparently it was not used very much, but I'd still like to err on the side of caution. What can I do to make sure it's safe for use? I assume a wash with boiling water and a Star San rinse before use would be adequate?

I've also been thinking of making a keggle for use as a boil kettle. I have kept an eye on Trademe for a keg, but I haven't spotted any cheap ones in/around Wellington so far. I have also found this keg at Keg Resources NZ, but I'm not sure if it's suitable as it is different to the conventional kegs that are usually used. I am using an electric element rather than gas heating, so would this keg suit my needs?

Thanks!

[Ralph]

An autoclave would be the best way... But at home you could try popping it into a pressure cooker for 20 min or something. Alternatively soaking it in something that contains a hot solution of sodium percarbonate to for a few hours before rinsing well and then sanitising with starsan should work. All the napisan type products have sodium percarbonate, just make sure you get an unscented one.

[Tilt]

To err on the side of caution I'd want to know what the flask was used for.  From a washing perspective probably the best you could do to cover all bases is hit it with a caustic wash (Sodium hydroxide), an acid wash (Starsan at twice usual strength - but thats a guess), maybe a bleach rinse and then boil some water in it.  It might be overkill but ultimately you've got to feel happy drinking what comes out of it.

Keg wise - I use one of those kegs as my kettle - but I use a burner so had to take the plastic sections off.  I'm figuring you'll need to take the top plastic section off to cut the top of the keg out.  Not sure how the bottom section will  stand up to a 90min electric element boil.  You could always try it with the base intact first up then take it off and make yourself a stand if it complains with the heat.

If thats all too much hassle -try a local scrappy with 6 pack of your finest in hand and ask them to keep their eyes out for a standard SS keg.

[Clinton]

Thanks for the suggestions. I can get NaOH reasonably easily, and have a lot of Star San, so I'll probably go with your method. 

If the shipping is cheap enough, I'll probably get that keg, as it looks like a viable option for $60.

[Damon Colbert]

An autoclave or pressure cooker would kill anything except the hardiest fungal spores.  But you'd be hard pressed to get your hands on anything big enough for an erlenmeyer.

We use Virkon in the lab.  It kills everything.  Standard procedure would be to virkon treat a flask after each use, if not autoclaving, so hopefully your flask might have already been sterilised.  You might be able to find Virkon online somewhere? Not sure how much it'll cost though.

Realistically I think a caustic wash, and a standard brewing sanitiser would do the trick.  There are not many things we grow in the lab that could withstand that.  Most common bugs are E. coli, Saccharomyces cerevisiae, and occasionally a few other fungi/moulds. 

[Liam Callaghan]

Bear in mind that if you do wash it, you could be destroying the perfect yeast and bacterial mix...

:p

I often run mine in the oven for an hour if they have been left standing for a while, same as with the pickling jars.