Storing Agar Wort

[reddog]

I made up a batch off agar and wort today to make some slants. on completion I left the remaining mix in the pot to cool. This left me with a solid puck 1 inch thick by 6 inch dia. My question is can I freeze this puck and use it again liquifying it in the pressure cooker as I sterilize it.

 

[raven19]

As long as boiling it does not affect the agar, I dont see why not - and if it does, just add some more agar after?

 

[reddog]

As long as boiling it does not affect the agar, I dont see why not - and if it does, just add some more agar after?

Yeh when it cooled I tipped the non stick pot over and ended up with puck. I have since slice the puck into quarters and placed in the freezer. I will give it a few weeks then run it through the pressure cooker for 25mins to autoclave it then pour it onto some Petri dishes to test it. Could be handy

 

[Sammus]

dont worry about freezing it, if you're going to pressure cook it anyway itll be sweet. ive got a few jars of leftovers at home that i heat up in a water bath and point into tubes to make slants when I need to.

Boiling won't affect agar at all, don't need to add any more

I pour my slants and pressure cook them, I can't imagine pouring it afterwards and keeping it sterile. Seems to be a common approach though, I might give it a crack some time.

 

[dreadhead]

Agree with Sammus, no need to freeze.
I would melt down your puck and pour it into a heat proof, covered flask of some sorts, about double the volume of your wort agar, and re-sterilise it in your pressure cooker. Once it has cooled down, make sure it is well sealed and chuck it in the fridge. When you need to pour some more plates or slants just melt your agar down again gently in a water bath (50-60 deg), which will minimise any condensation in your slant vessels. Just make sure you give your wort agar a good swirl to make sure the agar is evenly distributed throughout the media, and don't cap any of your vessels too tightly in the pressure cooker so any steam can vent.

 

[Sammus]

I'm not sure 50-60 will melt it. Agar has this weird property where it melts at like 90 but doesnt resolidify till about 50-60. I've never measured temps when I do it though, that's just what I read

Agar exhibits hysteresis, melting at 85 C (358 K, 185 F) and solidifying from 32-40 C. (305 - 313 K, 90-104 F)

 

[dreadhead]

My mistake Sammus, heat you wort agar in a water bath until it liquifies , then keep it in your 50-60 deg water bath to prevent it from re-solidifying.

Reddog, I'd also say don't prepare to much wort agar in advance as constant heating and cooling reduces the viability of the agar, just keep some wort (I think 1.040 OG is recommended) in the fridge and mix with agar powder as you need it.