Fair call CT - I am pretty sure I use your method posted many moons ago!
I tend to leave a blank slant out on the bench at room temp as a 'quality control' measure. If it goes bad then I redo the lot.
You can increase the effectiveness of the pot method by putting a weight on the lid ( there by increasing the pressure inside and the temperature ). I do this for about 45 mins.
Sterilisation is a temperature and time balance. For autoclave (using water vapour) it is supposed to be 123C for 15mins. If you go lower temp you need to increase the time.
Doing it at twice at boiling temp was the original method used ( ie heat to boiling, hold for a period, let cool to ambient, heat back to boiling and hold again ).
Anyway with slants you are soon going to know if they got contaminated or not.
Just find a method that works for you and your setup.
I use a large saucepan with an inch of water.
Inside place a pyrex container, place your items for sterilising in this.
View attachment 31988
Then simmer with the lid on for 15 minutes.
The steam will sterilise things nicely.
I tend to make blank slants up and put the lids on them loosely - so when it cools back down after 15 minutes, you can just screw them up tight - place in fridge, ready for slanting whenever you need them.
So where is the best place to purchase flat bottom test tubes?
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