No-pour agar or pouring agar in still air box?

tonight I poured agar into petri dishes (jars) in a still air box for the first time. I feel like I might have contaminated things (felt strange leaving the jar with agar liquid open for so long in the SAB), but will see if the dishes get contaminated.

anyone ever do the the no-pour method with agar? pouring the agar in the jars before sterilizing, and then just sterilizing all the jars, with agar already poured?

seems like it might mean less contamination, but is there a reason not to do it that way?

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I use a bottle with a narrow neck and opening to sterilise and pour agar (like a wine bottle or mini-version of a wine bottle). The small mouth reduces the chance of contaminants falling inside, while also making it easier to pour smoothly and accurately. If you’re working in a SAB with good technique there’s very little chance of contaminating your plates while pouring.

I’ve used the no-pour method with mixed results. The main thing to be careful of is ensuring the stack (of plates or jars) is not able to fall over, either during the sterilisation run or during the cooling phase. There is also the risk of boil-over (where the agar escapes the containing vessel(s)).

The no-pour method does offer some advantages: no waiting around to pour the plates, no danger of burning your hand while pouring the hot agar, no chance of contamination prior to inoculation.

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