How to sterilize mushroom spawn bags in a 23q Presto

[@MaleneMichaelsen-bo8fh]

What is the perfect mix for 10ml syringe spores? And du you hydrate the grains 24 hours before?

[@MauweeWauwee]

Hello Stipe & Cap Mushroom CO. I have an autoclave which does not have function to let pressure out on 15 PSI. It shuts completely and keeps around 15 PSI at 75 Celsius. How long should I sterilise my rye grain under those conditions? Or would it be better to go for around 45 PSI and around 115 Celsius?

[@StipeCap]

Are you sure your autoclave isn't capable of reaching 121°C at 15psi?

[@MauweeWauwee]

@@StipeCap im sure. Trying otherwise I would be using it not following manual. I've tried with agar and worked good at around 100 celsius and 30 psi for 30 minutes.

[@StipeCap]

Autoclaves are designed to run at specific temperatures that are directly correlated to pressure: 10psi = 115.5°C 15 psi = 121°C, 20psi = 126.11°C. Pressure is necessary to exceed the boiling temperature of water, it's the only reason why autoclaves/pressure cookers pressurize steam. What kind of autoclave do you own?

[@MauweeWauwee]

@@StipeCap Uteho ЧЕ-8 electro It shuts solid not letting anything out and when it reaches 75°C it has around 15psi. Heating element shuts down automatically and it keeps that pressure way better then heat. As far as I understand Presto 23 is designed to spew some of that pressure out while being heated constantly.

[@StipeCap]

I googled your unit, but I don't speak/read Russian, so I took a look at the valves on top of the lid. It appears as though you have on and off valves which would allow for steam to release from your cooker. Open whichever valve allows for steam evacuation, allow that valve to vent for the internal gases to be replaced by steam before closing the valve to build pressure for your cycle. If you don't purge the internal gas/replace it with steam, your unit will pressurize mixed gases resulting in lower temperatures.

[@danielmiller7603]

What model burner did you use? Is it the 120v 1,500w

[@StipeCap]

The CSR 3T

[@Rubo7]

Hey thank you for all the tips. I do have a question with the bags after they come out of sterilization. Do you seal the bags? Or just having them folded like that will keep them seal for a long period of time? I just want to sterilize more bags and put them on a shelf and have them ready whenever I need to. What do you recommend to do after pulling the bags out of sterilization if I'm not inoculating that day?

[@StipeCap]

You shouldn't let them sit long-term but the vacuum seal should hold, I've never run into problems with it.

[@Rubo7]

@@StipeCap I've read online from north spore. They say if you keep them in a room at room temp in a place out of direct sunlight you can store them for up to 2 months. I just don't know if they seal the bags. That's my main question is sealing them with an impulse sealer or just folding them over is enough. 🤷‍♂️

[@StipeCap]

@Rubo7 North Spore spawn producers have more experience than the average home cultivator, spawn production is one of the most difficult aspects of mushroom cultivation. So, yes it's possible to store perfectly executed spawn, however, most fail to achieve this prerequisite to long-term storage. The vacuum seal integrity will depend on the vessel utilized to sterilize your spawn bags, some units pull a vacuum better than others, the situation will dictate.

[@BobbyJpure]

Been having issues with my oat grain bags spilling out liquid and making the water nasty. Crazy ive done thousands of bags but occasionally still mess up. Smh

[@G23-k5r]

Is a trivet at the top really necessary ?

[@StipeCap]

It's a redundancy measure, a cheap insurance policy against safety plug and vent tube blockage from bag mishaps.

[@edouardrenaud5517]

if the bag is sealed, how do you put the spawn grain in?

[@StipeCap]

Could you rephrase? I don't understand the question. The bags are unsealed and loaded with grain before pressure cooking. If you mean inoculation post-sterilization cycle: peel the vacuum-sealed opening while in front of your flow cabinet, then inoculate and seal with impulse sealer or with a zip tie.

[@giovannipascal4404]

I thought only 1 hr was needed to sterilize in a canner? Is 3 hrs the actual recommended time for sterilization?

[@StipeCap]

Yes, 3.5 hours is the recommended time to sterilize large bags of grain.

[@Jugg215]

If you’re just using quart jars you can go for 90 minutes to 2 hours but when rocking these big bags you wanna go longer.

[@J155P]

Do you sterilize substrate in your presto? If so, how many bags do you typically do?

[@StipeCap]

Yes, you can sterilize supplemented sawdust blocks in the same way you'd sterilize spawn.

[@Max-bh2rc]

Hey man, I appreciate all of your information and work. You do a really good job at explaining everything, thank you for that. I have a few questions that I hope you can answer. First, what is the dry weight of millet per bag before you hydrate them? Second, how many of your 5lbs sub bags are you able to inoculate with one of your grain bags? Third, would 14A .5 micron unicorn grow bags would work for this? Finally, I am using a gas stove. My PC is some brand that Canadian Tire carried a few years ago and is no longer available, i've had no issues with jars but do have some concerns that the hot metal could melt my bags. Would bringing the boil/heat up slower be the play here? This last one is a little vague, I may just have to mess around with it a few times but don't really want to dick around with a pressure cooker and stuff melting inside. Thanks again!

[@StipeCap]

I wouldn't recommend . 5 for spawn but the bags should be fine if you keep the flame low.

[@Max-bh2rc]

@@StipeCap Thanks for the reply man, are you able to chime in on the other questions?

[@StipeCap]

@Max-bh2rc feel free to join me at shroomery.org or our discord server for more in-depth information.

[@Max-bh2rc]

@@StipeCap Got it, thanks man. I see the benefit of having this discussion in the community. Ill make a thread shortly.

[@Max-bh2rc]

@@StipeCap Hey, I made a post on shroomery but not exactly regarding the questions which I initially asked you. It is in the gourmet section. If you have the time to respond, I would grateful for your input.

[@bradsmith3346]

Are you sterilizing for 3.5 hours, or how long do you run the cycle?

[@StipeCap]

I sterilize bags for 3.t-4 hours after purging the vessel.

[@mushyynelvz2552]

Hiya, fellow mycologist here, could you tell me how much those magnets weigh cumulatively, and the internal pressures being achieved ? I'm also using the same Presto 23qt cooker, My pressure gauge broke, but I know its still working because the pressure weight still wobbles and hisses rhythmically. Thanks !

[@StipeCap]

No idea but a replacement gauge is like 20-30$ on Amazon, get er done. My stack allows me to exceed 20psi in silence, if I want.

[@ELIMM-wg5ky]

Just glue 3 quarters onto the jiggle thang

[@PPP-on3vl]

​@StipeCap at what pressure do u run it?

[@StipeCap]

15+ psi

[@GeraldMacDad]

​@@ELIMM-wg5ky Aluminum duct tape and a quarter works best for me. Magnets and glued quarters pop off. The aluminum tape works a treat.

[@justbassdonthate5908]

Purging the pressure cooker? I’ve never done it and will never do it and have always had stellar results.. people need to drop all these old-school methods. Growing mushrooms is quite easy. It’s just very tedious no need to add a bunch of extra mumbo-jumbo to it. Not saying to cut corners, but some corners shouldn’t be there.

[@StipeCap]

It's not "old school", this is how autoclaves function. Dalton's law covers this phenomenon: Quote: According to Dalton's law of partial pressures, the total pressure by a mixture of gases is equal to the sum of the partial pressures of each of the constituent gases. The partial pressure is defined as the pressure each gas would exert if it alone occupied the volume of the mixture at the same temperature. If you don't vent/purge the pressure cooker or autoclave you won't reach the appropriate internal temperature.