How to Sterilize Mushroom Substrate Without a Pressure Cooker?

How to Sterilize Mushroom Substrate Without a Pressure CookerOne of the growing trends that picked up the interest of many home growers is mushroom cultivation. Well, we do not find that surprising at all! Want to know why?

Mushrooms are a pretty versatile food item, and you can use them in multiple ways. Even our culinary team loves to prepare different foods with it.

Like others, we also wanted to get into mushroom cultivation. However, getting a large pressure cooker was way out of our budget. So, we learned how to sterilize mushroom substrate without a pressure cooker. And trust us; the methods we have mastered works the same if not better than the pressure cooker process.

Want to learn about the methods? Stick until the end of this article!

Why Mushroom Substrate Requires Sterilization?

Before we get into describing the alternative processes that you can follow to sterilize mushrooms, we would like to ensure that you know why mushroom substrates require sterilization in the first place.

Well, if you have tried to cultivate mushrooms without sterilization, you might have noticed that the yield becomes exceptionally low. What causes this low yield?

Contamination! The sterilization process will kill any bacteria, fungi, viruses, or mold that might be present. And that will make the shrooms grow to their fullest.

But that is not all! Sterilization will ensure that the substrate has a proper amount of water when you add the spores.

That will increase the yield and ensure that no failure occurs when you try to get higher overall output from your mushroom growing project.

4 Ways to Sterilize Mushroom Substrate Without a Pressure Cooker

Ways to Sterilize Mushroom Substrate Without a Pressure Cooker

We guess it will not be necessary to state that you do not always require a pressure cooker to sterilize mushroom substrate. There are other methods that will offer the same results. Sometimes, some of the techniques even provide a better result than the pressure cooker sterilization process. Do not believe us? Continue reading!

Method 1: Cold Sterilization

The cold sterilization process might be the cheapest method to sterilize the substrate. How so? Well, the name gives it away! You will not require any heat, eliminating the need for electricity or fuel. And you would need to follow these steps for this method:

Step 1: Prepare the Medium

First and foremost, you would need to prepare the medium. For most cases, home growers will utilize straw. Decide how much of it you will need and keep it in a separate place. Then, get yourself a container where you will be soaking the medium in. Clean it up with alcohol sanitizer and rinse it down with water.

Step 2: Get the Right Chemical

Next up, you would need to get a suitable chemical. You can either pick the hydrated lime or chlorine for this process. In the case of hydrated lime, it will increase the pH value of the solution and kill most of the contaminants by doing so. And this chemical will be most suitable for oyster mushrooms.

On that note, you will not be capable of using the dolomitic lime for this process, which is primarily used for gardens. Instead, get the calcium hydroxide. It should be available in any agricultural supply store.

Other than that, you can use chlorine. Instead of raising the pH level, the chlorine will oxidize the solution and kill almost all available pathogens. Also, you will not have to worry about chlorine damaging the spores. It will get neutralized before you add the spores to the medium.

Step 3: Add the Chemical to the Solution and Mix in the Medium

For lime, you would need to use 300 grams for every 55 gallons of water. Mix it up properly, and then let the medium soak for at least 24 hours. When it comes to chlorine, you need to use a solution that has a strength of five parts per million. Soak up the medium and leave it like that for 24 hours.

Step 4: Drain the Solution

Last but not least, you would need to drain the solution after 24 hours. There will be no need to rinse the medium before inoculating the spores.

Method 2: Scalding

The cold sterilization process does not require any heat. However, for this process, you will need heat. But do not worry, the process is pretty simple, and you would not have to go through any intricate steps.

Step 1: Boil the Required Amount of Water

First of all, calculate how much water you will need by considering the amount of the medium. Boil the water by keeping the temperature at around 80 degrees Celcius. Let the water boil for a reasonable amount of time because if there are contaminants inside the water, the water will further contaminate the medium.

Step 2: Pour the Water over the Substrate

After the water comes to a proper boiling state, you would need to soak the substrate with it. Leave the medium in that condition for at least 60 minutes. But we would recommend waiting for at least 90 minutes.

Step 3: Drain the Water

Finally, you will need to drain the medium. Give it a good rinse with semi-hot water if you can. However, do not leave the substrate dry for an extended time. That will make the medium get contaminated again. And you would not want that to happen, would you?

Method 3: Peroxide

It is undoubtedly possible to sterilize the substrate using peroxide. And like the other methods we have described, this one is easy. So, without further ado, let us walk you through the process.

Step 1: Soak the Medium into Water

Before adding peroxide to the substrate, you will need to soak it in water for a while. Once it is all soaked up, drain it. Repeat the entire process. In other words, you would need to soak and drain the medium twice with water.

Step 2: Prepare the Peroxide Solution

Now, get yourself 3% peroxide. You would have to prepare a solution with it. For 1 gallon of water, add 1 liter of the chemical. Ensure that you do not use too much, or else the chemical might degrade the quality of the substrate. So, be extra careful while you are mixing the solution.

Step 3: Pour the Solution into the Substrate

Next up, you would need to pour the solution over the substrate. Submerge the medium entirely and leave it for an entire day. After 24 hours, drain all liquid from the medium and rise it.

Follow the same rinsing process as you did in step. As in, you would need to rinse it twice. And the substrate should be ready for the inoculation process.

Method 4: Cold Fermentation

The cold fermentation process is something that we would not recommend if you are in a hurry. It requires a reasonable amount of time and effort. However, it is highly effective and will not make you break your bank. Here are the steps that you would need to follow:

Step 1: Pack the Medium

To start with, you would need to pack the medium inside fabric bags. Do not use plastic bags because those will not work. Put all of the substrates into the fabric bag.

Step 2: Submerge the Fabric Bag

Then, submerge the entire bag into the water. It would be better to pick a barrel or a bucket for the submersion process. You would need to leave it for at least one week, but we would recommend keeping the bag submerged for at least two weeks.

During this period, the anaerobic micro-organisms will grow and ferment the medium. That will eventually kill all of the pathogens present in the substrate.

Step 3: Drain the Water and Expose the Substrate to Air

Lastly, you would need to drain the bag properly. After that, spread it out on top of a clean surface. Leave it for a while. The air will kill eliminate all of the remaining anaerobic micro-organisms. Once the substrate dries up a little, inoculate it with the spores.

Things to Consider Before You Follow Any of the Sterilization Methods

You need to keep a few things in your mind before following any of the methods we have mentioned above.

Wear Safety Equipment

Firstly, while handling chemicals such as hydrated lime and chlorine, you need to wear a pair of gloves. If those chemicals come in contact with your skin, you might end up with rashes and reactions.

Follow Proper Ratio for the Solutions

Secondly, follow the ratio properly while making any of the solutions. If you use too much, the chances of the chemicals damaging the growing capabilities of the substrate will be comparatively high.

Inoculate Right After Sterilizing

Finally, inoculate the spores right after finishing the sterilization process. If you leave the medium for an extended amount of time after sterilizing it, it might get contaminated again.

Frequently Asked Questions

Which substrate should I use for oyster mushrooms?

You should pick straw as a substrate for oyster mushrooms. But do remember that things can get a bit messy while handing straws. However, the good news is that it is pretty cheap and highly effective at growing oyster mushrooms.

What type of mushroom should I pick if I plan to use manure?

If you are choosing manure as a substrate for the growing process, pick the button mushrooms. It would be better to pick the manures that have gone through the two-phase composting process.

What is pasteurization?

Sometimes, people often mix up pasteurization with sterilization. Both of them do the same thing, which is to eliminate the contaminants from the substrate, but they are not the same thing.

For pasteurization, you would need to heat up a bulk amount of substrate within the temperature range of 150 degrees to 185 degrees Fahrenheit. And mostly, people would use steam for the heating process.

Final Words

Starting a mushroom farm right at home will allow you to the finest quality of shrooms without having to pay a hefty price. You will also be capable of enjoying fresh shrooms without needing to go through the isles of the supermarket. And as you can see, you do not really need a pressure cooker to sterilize the mushroom substrate.

Just pick any of the methods that we have discussed in this discussion regarding the topic of how to sterilize mushroom substrate without a pressure cooker and start inoculating the spores.

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