Australia's Science Forum

Anyone successfully frozen liquid agar for later use?
I have a beutiful batch of tomato agar, last minute changes to plan resulted in me having lots left over, It is quite a fiddly agar to make as you know!
and if it can be saved it would be really handy

I do believe they can NOT be frozen and then restored, very well. Some one turned the fridge up to near frozen, and the agar plates were frozen, we just could not use them, at all.

Yes, I had a feelling that might be the case.
What a waste..
Wonder if it will successfully compost?!

Can you just leave it sealed in a jar in the fridge then reheat and pour it into plates next time it's needed? Or have you already poured the plates? It does seem a shame to have to throw it out!

I'd try keeping it in the fridge. Other agar seems to keep quite well. The worst that can happen is you'll have to throw it out.
Julie

We bulk batch our various agar stocks and store them in the fridge in rubber stoppered 500ml conical flasks. When we need them we melt the required amount in the microwave and pour the plates. Great for short notice pracs!

.... Used to do heaps of nutrient agar plates. Make a batch of couple of litres, pour 20mL into those little McCartney bottles, screw the lids on and bung into fridge. When we wanted plates, (which was every day) we'd stand the reqd amount of bottles in a saucepan with water and reheat until agar was 60 deg. Using the microwave to reheat would be good, but you'd have to unscrew the lids so the pressure wouldn't build up.

I've also kept nutrient agar plates in fridge for about 10 months. Control on these was no different to control on freshly made ones.