Autoclave technique – loss of medium! - (Jun/08/2007 )

I was told when ever you put bottle of medium in an autoclave or pressure cooker that you needed to turn the cap until it was tight and then back half a twist, to ensure the bottle did not explode! But I have noticed that I lose quite a lot of medium this way (especially in the pressure cooker) and I assume that if media is getting out autoclave steam is getting in and messing with my concentrations…… Should I cap the lids tighter and risk explosion?

Any ideas will be appreciated........

Many thanks,

Evejoss

This is why you run the liquid cycle on the autoclave, it decreases the pressure more slowly at the end of the cycle so that the liquid will not boil (ie: temperature is below boiling point at that pressure throughout the autoclave cycle) this should help, also we always put bottles in a pan of water during autoclaving to help reduce temperature difference stress on the glass resulting from the liquid inside being hotter than the air outside... still lose a little volume maybe but it is not significant loss.

HTH

i always keep the lids of bottle loose when i autoclaved them. and i wrap it with aluminium foil so that no contamination could occur. for flask containing culture media i use foam cap and then wrap with foil and autoclave and after autoclave i remove the foil instantly

If the cap is not too loose, the loss is not a lot. And if the media is LB, its not a big deal.

so, it doesn't matter with empty flasks??!!!

Hmm perhaps you have a very volatile solution? I always untighten it before I autoclave it.