Ok so as a carry over from a previous thread I thought I'd share my technique for sterilising vials.
I see alot of practices that claim sterile but are far from sterile, if you want actual sterile vials this is one way to achieve that, although I have yet to swab my vials and put it on agar but I trust the process.
I pulled alot of this from growing mushrooms, adapted and used equipment I had on hand, it's much the same process but you have to be alot more sterile with mushroom growing than you do bottling gear.
Clean your vials as per lab glass cleaning instructions which you can find online:
Wash and rinse both vials and rubber stoppers in tap water and dish soap then rinse 3 - 4 times in distilled water, place in the oven to completely dry, usually 20 mins or so, wait for them to cool to the touch.
Place them into autoclave bags with the rubber stopper just above the vial, do not seal the vials, it helps if you have self sealing bags but the non sealing ones are cheaper and painters tape is fine to seal them with.
Place the packets into a PP5 bucket, this is important, it must be PP5, it'll have a recyclable symbol with a 5 in the centre, these can with stand the heat of a pressure cooker, everything else will melt, the one I have is 5 litres, cut a hole in the lid of the bucket and stuff with poly fill, again must be poly fill as that handles the heat, the hole stuffed with polyfill allows pressure relief while reducing the moisture inside the bucket, your bucket will most likely implode without it.
Cover the top with tinfoil to protect any water drops dripping onto the polyfill.
Place into the pressure cooker with 2.5 quarts of water at the bottom.
Turn on high and allow steam to escape for 10mins, place the weight on and bring the pressure up to a minimum 15psi, turn it down and hold it steady, I run mine at 18psi.
20mins is probably fine at 15psi but I like to run it for 45 just to be sure.
When it's cooled down you can remove the bucket, it's contents will be sterile untill you open it, so could sit on a shelf for months and be completely sterile inside.
Once everything has cooled down you can manouver the rubber stoppers onto the vials through the plastic without opening them, they should stay sterile in the packet for upto a year.
You can also fill them while still in the packet if using a syringe filter, just peirce right through the plastic and rubber stopper and fill them up, once full remove them from the packet and cap them.
If using a bottle top filter you'd need a flow hood or at a minimum a still air box to remain sterile while filling.