Air exchange for grain jars

[Fezza]

I've been doing some research on the requirements of air exchange for grain jars, but the common knowledge bases do not provide any information apart from suggesting it or omitting it

The Teks on the shroomery suggests it is required, but the PF tek omits this.

The reason I am asking is that I have had an incident with one of my beloved button mushroom jars. I had made a small hole on the top of the jar and placed in it a cotton ball so that air exchange was possible and restricted contaminates to a degree. On a daily basis I would shake my jar delicatly to distribute the mycilium. Roughly about a week after first inoculation a green lifeform of some sort started growing from the bottom half of the cotton ball(inside the jar). Needless to say, it spead, and rendered my jar useless.

What I'd like to know is: Can I omit the small air exchange provided by the hole/cotton bud?

I have read in some posts that mycilium growth is hampered by the lack of oxygen and the increasing amounts of CO2 produced. This also does not help since button mushrooms are notorius for being one of the top asperators.

Although this is a simple question, I don't think this has been well documented, so past experiences with both methods would really shed some light on the topic.

Peace.

Edited November 11, 2006 by Fezza

[occidentalis]

It definitely helps with big jars. Cotton wool? I'm not sure if that would provide fine enough filtering. Most people use polyfill. I usually do. I tend to be pretty slack with sterile technique and do get some contams sometimes but I haven't seen anything that would suggest the polyfill air exchange is the cause of it.

Also, don't shake your jars every day. Every time you shake, you are delaying immediate growth in exchange for long term increase in growth rate. But if you shake every day, you are constantly delaying without seeing any of the long term payoff. They have to recover! Shake once after inoculation, then again a few days after you see the first visible growth. Then leave the poor things alone to grow in peace.

[Hyphal]

You actually want GAS exchange for your jars, not AIR axchange, and yes its very important.

http://www.shroomery.org/forums/showflat.p...&PHPSESSID=

Cotton wool isnt a synthetic fibre so is open to introducing contams to your grow - go to the pet store and get a bag of polyfill instead (used in fish tank filters, or even larger bags can be found in Kmart - its used for stuffing toys and pillows). Your grow could also have been contaminated from another aspect of yoru technique so dont rule that out either.

As Creach stated, dont shake the jars while their trying to colonise! Just once after innoculation, and once again when they are about 25% colonised.

[foolsbreath]

a theory I have been working on uses disposible milipore filters fitted into the lid (0.1 micron), secured by silicon, sterilized at high pressure (checked this and the millipore filters can survive 120 degree in a 30 min wet autoclave cycle). You then have a sterile environment on the inside of the jar. You can then inject air into the jar in one filter, with the exhaust gas coming out the other. This means you can easily exchange the entire gaseous content of your jars every day. To be extra careful, you can employ a third filter when drawing the air into the syringe used for ther gas exchange, no contamination!!

Edited November 12, 2006 by foolsbreath

[foolsbreath]

and you can easily supplement with water, H2O2 and dissolvable nutrients when needed (pre filter so you don't block up the filters fitted to the lid) without concern for contamination .

[AndyAmine.]

What kind of filters are you using? syringe filters?

You can also draw in sterile air by holding the tip of the needle in a flame.

[Lono]

What kind of filters are you using? syringe filters?

You can also draw in sterile air by holding the tip of the needle in a flame.

Just a thought Andy, but wouldn't all the oxygen be burnt off the air by using that method?

[mescalito]

I think Fezza's more worried about gas exchange during the colonization in the jar.Just like yeast with brewing beer there are gaseous emissions from the mycelia so some exchange is needed.

Your main problem as creach said is that your using an infectable filter ie cotton.Also shaking the jars will wet the filter,reducing it's ability to breathe and increasing the chances of drawing in external contaminants.

The best method is the old double foil and dry vermiculite barrier.

Keep at it mate you'll learn heaps through failures

[Hyphal]

You cant use a verm barrier with grain jars though....

[Fezza]

I wasn't aware of polyfill being more a effective filter then cotton, but cotton being nature is probably more susceptible to being colonised by foreign organisms.

After looking at the link that Fusion supplied, I've come to realise that air/gas exchange is very important for the growth of mycelium, especially in a jar, where gas exchange is not so prevalent.

I was going to try loosening the top and using the aluminium foil method, but I think the amount of gas exchange would not compare to the polyfill method. Although, the aluminium foil method seems quite popular and seems to be successful.

I agree with Lono as far as contaminate free air drawn from a lighter goes. If you where to draw air from a flame of some sort, you would only collect CO2, but depending on what you are using for a source, you may also get butane or even atomised alcohol.

But its all a learning process. Thank god I've been practicing with the common Agaricus bisporus.

[occidentalis]

I used to use the al foil method, but it is much more fiddly and difficult than polyfill.

[mescalito]

You cant use a verm barrier with grain jars though....

I beg to differ

No direct cantact between the substrate and the barrier.

It's simple:

1)fill jar with substrate (Use Rev's rice-tek or rye-tek)

2)"concave cup" one layer of foil and top with dry verm

3)poke 3-5 needle holes in this foil

4)top with foil and poke injection sites

5)PC jars with another layer of foil loosely over the top and let cool

6)Inocculate

Viola!!

[Hyphal]

Very very interesting method... I stand corrected!

[spiders]

with grain jars i just leave an inch of air at the top of the jars - and air exchange isnt as much of a problem as when i used to do the pf tek and leave a layer of verm which actually seemed to contribute to jars stalling from poor gas exchange.