High altitude autoclaving
Posted 17 February 2010 - 05:04 PM
My question is whether longer durations at lower pressures (10-11 psi) will equate or do I just need to get an new autoclave which will support increased pressure? Thanks in advance!
Posted 17 February 2010 - 11:16 PM
But: you have your medium in (loosley) closed bottles? This could influence the sucess of your attempt, as the steam has to get to the medium to sterilise it.
Alternative: you have your bottles not closed enough so there are bacteria getting in from the air when cooling the media before use
Or you have a contamination in your laminar flow.......
Increasing the time is only useful when autoclaving huge amounts (like three four liters in one bottle) as there is more time needed to heat and saturate your medium with hot steam. Otherwise longer times can burn your medium so it will not work as you expect it.....so be careful with longer times and higher pressure.
Posted 18 February 2010 - 06:40 AM
Posted 18 February 2010 - 01:04 PM
Then you (or the automatic system) close the gauge and the pressure increases inside, here there might be some influence how the autoclave is regulated and what type of gauge is used: Most pressure gauges are designed to measure the amount of pressure above the ambient atmospheric pressure (and not absolute values), therefore the gauge might open too early to let steam off, because the system detects a too high pressure inside (as it compares the pressure inside to a too low ambient pressure outside). Then the temperature inside is always too low.
Actually I don't know if the altitude you are has that much influence on pressure and boiling temperatures, but there should be people how now that.
If it's really a problem you (or the service people) might can solve it in that way, that the gauge is calibrated for the lower ambient atmospheric pressure.
...except casandra's that belong to the funniest, most interesting and imaginative (or over-imaginative?) ones, I suppose.