Pressure Cookers & Sterilization for Mushroom Cultivation (Plus a Low-Tech Alternative)

As you take a deep dive into the exciting world of DIY mushroom cultivation, you’ll probably want to invest early on in a pressure cooker or autoclave for sterilizing all your growth medium. There are a lot of options out there, so we made this video to help you make an informed decision, learn how they work, and consider some great alternatives to sterilization.

A pressure cooker will allow you to make your own grain spawn, agar plates, liquid culture, and bulk substrates, saving you money and helping you deepen your connection with your mushrooms.

In this detailed how-to video, we’ll discuss sterilization methods and why they’re important. Then we’ll compare the pros and cons of a variety of different pressure cookers to help you choose which one is right for you, including Instant Pot, Presto canners, All American brand sterilizers, and affordable commercial autoclaves. We’ll also talk about pressure cooker safety and offer some tips for working with mushroom grow bags.

In part 2, we’ll go over standard operating procedures, explaining how to safely use a pressure cooker for a variety of different mushroom cultivation applications. This section includes specific information for using Instant Pot and All American pressure canners.

At the end, we’ll also show you a useful method for making grain spawn and other mushroom substrates without a pressure cooker, using a form of fractional pasteurization called tyndallization. Not only is this a good budget option for the hobby grower, this technique can also help you scale up by using a bulk pasteurizer. We’ll wrap up with some ideas for how to build one and why this is a great project for off-grid mushroom cultivators.

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Made with love by Fungaia, a heart-centered, donation-based mushroom company:
https://www.fungaia.life/

For the best, most reliable and super affordable mushroom genetics and liquid culture, visit our favorite culture library:

True Blue Genetics
https://truebluegenetics.org/?coupon=FUNGAIA
Discount code: FUNGAIA

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Recommended Pressure Cookers, Autoclaves & Parts:

Instant Pot Duo
https://amzn.to/3W2sUSl
(Now there's an 8-quart model too)

Vintage 21qt Presto/National Pressure Canner
https://ebay.us/yBsuA8
(Replacement gasket: https://amzn.to/3zGgtnB)

All American 941 41.5-Quart Pressure Canner
https://ebay.us/Q25MUr
Overpressure plug: https://amzn.to/3LlTTTQ
Spring-loaded Petcock: https://amzn.to/4f1y9dq

150L Electric Vertical Steam Sterilizer
https://ebay.us/evnqyo
(Get the 220V!)

Bulk Pasteurizer Parts
Hot water valve: https://amzn.to/3Y0naeu
Turkey fryer: https://ebay.us/Wz37dz
Just the burner: https://amzn.to/3XYFVPp

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Standard Cook Times (15 psi / 1 bar):
Liquid culture / agar media: 35-45 minutes
Grain spawn (jars): 90 minutes
Grain spawn (bags): 1 hour 45 minutes
Sawdust blocks: 2 - 2.5 hours

Cook times for Instant Pot:
LC / agar: 1 hour
Grain jars: 2 hours
Sawdust / grain bags: 3+ hours

Cook Times for Tyndallization:
Round 1: 1 hour @ 165F
Cool 24 - 48 hours
Round 2: 2 hours @ 190F
Cool 24 hours
Round 3: 2+ hours @ 190F

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Other Useful Supplies

True Blue Genetics: the best liquid culture out there
https://truebluegenetics.org/?coupon=FUNGAIA
This is the last genetics provider you will ever need!

Gourmet and Medicinal Mushroom Cultures from Fungaia
https://www.fungaia.life/shop/species/

The Fungaia Cube Kit
https://www.fungaia.life/shop/kits/?q=cube_kit
An organic, all-in-one grow kit for dung-lover mushrooms

Pre-Sterilized Grain Bags
https://www.fungaia.life/shop/fertilesubstrate/?q=7lb_grain

Pasteurized, Manure-Based Mushroom Substrate
https://www.fungaia.life/shop/fertilesubstrate/?q=poo_sub

Monotubs and monotub filters: Microppose
https://microppose.com/r?id=h776jn
Discount code FUNGAIA

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Created by Paul Lynn. All rights reserved.
Made with free stock footage from Pexels.
Music by Paul Lynn.
© 2024 Alembic Enterprises LLC
Walla Walla, Washington

0:00 Intro
1:14 Background Info
3:14 Sterilization Methods
7:00 Steam Sterilization Explained
8:32 Vacuum Issue
9:23 Using Pre-Sterilized Substrates
9:58 Choosing a Pressure Cooker: Pros and Cons
16:07 Heat Source
16:55 Low-Tech Alternative
17:40 Grow Bags & Safety Tips
18:57 PART 2: How to Use a Pressure Cooker, Step-by-Step
31:00 Instant Pot
34:26 All American Pressure Canner
37:27 PART 3: Sterilizing WITHOUT a Pressure Cooker
39:28 Science of Tyndallization
40:39 Tyndallization Procedure: Times & Temps
42:38 Bulk Pasteurizer
46:32 Outro