Almost very reference to preparing flasks uses a pressure cooker to sterilize the flasks. But on the Lotte and Thomas website they describe using an oven set to 150 degrees C (about 300 F) to sterilize the flasks. Has anyone done it using an oven or have any comments on this method?

I have no experience with that! But I think read somewhere that that could be just as effective but it takes longer...but don't take my word for it!!! LOL!!!

I'm assuming that this is before you put the plants/seed in the flasks??
I would think that you can do it, because the temperature is high enough to kill bacteria.

Now I wonder if you could sterilize them by dropping them in a pot of boiling hot water??

I'm assuming that this is before you put the plants/seed in the flasks??
I would think that you can do it, because the temperature is high enough to kill bacteria.

Now I wonder if you could sterilize them by dropping them in a pot of boiling hot water??

Yes, this is before putting the seeds in the flasks.

I doubt if boiling water would do it. The reason for the pressure cooker is the higher temperature that it creates.

Then couldn't you put it in your oven at about 500 degrees if you wanted higher heat?
My oven personally has a CLEAN setting that makes the oven go to like 700 degrees, and I think that should be suitable!?!?

Then couldn't you put it in your oven at about 500 degrees if you wanted higher heat?
My oven personally has a CLEAN setting that makes the oven go to like 700 degrees, and I think that should be suitable!?!?

Can the flasking container withstand that heat?

Pressure cookers are cheap. Don't fool around with an oven. You probably won't get 100% sterilization. It has and can be done, but if your serious about flasking, even a cheap pressure cooker will be better.

At 150 degrees C at normal pressure, your media (which is 95% water) will boil at about 100 degrees. You need a temperature higher to kill all the bacteria and stuff. 121 degrees C for about 15 minutes is whats needed to kill everything.

The only way to achieve 121 degrees C is with pressure. At normal pressure, water boils at about 100 C, no matter how hot the environment is. The water will always be 100 C. To increase the temp of the water, you have to make it harder for the liquid water molecules to become gas. Increasing the pressure accomplished this.

Hope this helps.

Kyle

Another comment about the oven technique. Raising media to 300 F and above will alter its chemical properties, you won't have what you thought was in the container. In addition stoppers can't tolerate this kind of dry heat either. Finally, if you're using anything other than pyrex containers, they will break at these elevated temperatures. Stick with a pressure cooker.

Ken Brewer

Another comment about the oven technique. Raising media to 300 F and above will alter its chemical properties, you won't have what you thought was in the container. In addition stoppers can't tolerate this kind of dry heat either. Finally, if you're using anything other than pyrex containers, they will break at these elevated temperatures. Stick with a pressure cooker.

Ken Brewer

:iagree::iagree::iagree:

Ramon:D

Pressure cookers are cheap. Don't fool around with an oven. You probably won't get 100% sterilization. It has and can be done, but if your serious about flasking, even a cheap pressure cooker will be better.

At 150 degrees C at normal pressure, your media (which is 95% water) will boil at about 100 degrees. You need a temperature higher to kill all the bacteria and stuff. 121 degrees C for about 15 minutes is whats needed to kill everything.

The only way to achieve 121 degrees C is with pressure. At normal pressure, water boils at about 100 C, no matter how hot the environment is. The water will always be 100 C. To increase the temp of the water, you have to make it harder for the liquid water molecules to become gas. Increasing the pressure accomplished this.

Hope this helps.

Kyle

I get it now! Thanks!! :thumbsup:

One could probably pick up a pressure cooker at a garage sale, for a most reasonable price!

Almost very reference to preparing flasks uses a pressure cooker to sterilize the flasks. But on the Lotte and Thomas website they describe using an oven set to 150 degrees C (about 300 F) to sterilize the flasks. Has anyone done it using an oven or have any comments on this method?

That was how my dad always did it. In the rare cases where there was contamination afterwards, he used a magnifying glass to burn the contamination away with sunlight.

Kim

That was how my dad always did it. In the rare cases where there was contamination afterwards, he used a magnifying glass to burn the contamination away with sunlight.

Kim

Maybe everyone knows that already, but Ive never heard it and thats a neat little trick! :thumbsup:

Maybe everyone knows that already, but Ive never heard it and thats a neat little trick! :thumbsup:

I think it is fun to do that with a dead leaf every once in a while.