Urban Spore

How To Make Master’s Mix Substrate

Mushroom cultivation has been a popular hobby and industry for centuries, but as the demand for gourmet mushrooms continues to grow, so does the need for effective and efficient growing methods. One such method is the use of Masters Mix substrate, a specially formulated blend of organic materials that provides the ideal environment for mushrooms to thrive. With its unique composition and ability to support healthy growth, Masters Mix substrate has become a go-to choice for mushroom growers looking to produce the best, most vibrant, and highest yielding mushrooms. In this article, we will explore the benefits of using Masters Mix substrate and provide tips for successfully growing gourmet mushrooms using this innovative growing medium.

What Is Masters' Mix?

Masters Mix is a specialized substrate designed for growing gourmet mushrooms. It is a carefully formulated blend of organic materials such as hardwood sawdust & soybean hulls. The mix is optimized to provide the ideal environment for mushroom growth, including the proper balance of moisture, nutrition, and aeration. The composition of Masters Mix is unique, with each component serving a specific purpose in supporting healthy and vigorous mushroom growth. As a result, it has become a popular choice among mushroom cultivators looking to produce high-quality and bountiful yields of gourmet mushrooms.

king oyster mushrooms

Does Masters Mix Need Sterilising?

Masters Mix substrate, like other supplemented substrates used for growing mushrooms, needs to be sterilized before inoculation to ensure the absence of harmful microorganisms that can compete with the mushroom mycelium for nutrients or cause contamination. Sterilization is the process of eliminating all living organisms, including bacteria, fungi, and viruses, by exposing the substrate to high temperatures and pressure for a set period.

The sterilization process also helps to create a clean and favorable environment for the mushroom spores or mycelium to grow, as it eliminates any existing microorganisms that could potentially harm or hinder the growth of the mushroom mycelium. This is crucial as the mycelium, the vegetative part of the mushroom, requires a sterile and nutrient-rich environment to grow and colonize the substrate successfully.

Sterilization is necessary for Masters Mix substrate to ensure that the mushroom cultivation process starts with a clean slate and that there are no unwanted microorganisms that could cause contamination or reduce the yield and quality of the final product. 

Fully Colonised Pink Oyster Grow Kit

What You'll Need

To make masters’ mix you will need an equal weight of soy hulls and hardwood fuel pellets. This is to be hydrated to 60%. Use the following recipe to produce 2.3 kg of substrate which is inoculated with 200 grams of grain spawn.

  • Fast fruiting time: The Fast Fruiting Mix is optimized for fast fruiting, allowing you to harvest your mushrooms in as little as 10-14 days, which is significantly faster than traditional substrates.
  • High yield: The mix is formulated to provide the ideal environment for mushroom growth, which can result in high yields of healthy and vibrant mushrooms.
  • Easy to use: The Fast Fruiting Mix is simple and easy to use, making it perfect for both novice and experienced mushroom growers.
  • Consistent results: With its unique composition and fast-acting properties, the Fast Fruiting Mix can produce consistent results, ensuring that your mushroom harvest is always of the highest quality.
  • Nutrient-rich: The mix is made from a carefully selected blend of organic materials, providing mushrooms with all the nutrients they need to thrive and produce healthy fruiting bodies.
  • Sterilized: The mix is sterilized before use to eliminate any harmful microorganisms that could compete with the mushroom mycelium or cause contamination.
  • Versatile: The Fast Fruiting Mix can be used with a wide range of mushroom species, making it a versatile substrate for any mushroom grower.

Step 1. Weigh Dry Ingredients

Using kitchen scales each of the dry ingredients. Mix together thoroughly before adding water.

If using a mushroom grow bag I recommend mixing the substrate directly in the bag. This recipe is ideal for filling 1 x [20x12cm] bag or 2 x [13x12cm] bags.

If using a glass jar we recommend keeping the size small due to a lack of ventilation. Ensure that a hole is placed in the lid with a micropore tape filter in place.

Hardwood fuel pellets in a bowl

Step 2. Add Water

Use kitchen scales to weigh water in grams for accuracy. Add water to the dry ingredients in the mushroom grow bag. Leave sit for 5 minutes to allow for the dry ingredients to absorb the water.

Now the bags are ready for folding. Learn how we fold grow bags for sterilisation in the link below.

making masters mix

Step 3. Sterilise

Once the substrate has begun to absorb water the grow bag can be folded over itself and packed into the pressure cooker for sterilising. 

Alternatively, if you are growing in glass jars I recommend creating a channel within each jar using the handle of a spoon. After sterilisation this channel will be be filled with grain spawn.

Sterilise the substrate for a minimum of 90 minutes. If you are using an electric bench-top pressure cooker you may need to extend cooking times.

Learn how we load a pressure canner in the link below.

  • Large capacity: The Presto 23 quart pressure canner has a large capacity, making it ideal for sterilizing a significant amount of substrate at once, which can save time and effort.
  • Versatile: The Presto 23 quart canner can also be used as a regular cooking pot or steamer, making it a versatile tool in the kitchen.
  • Safe and reliable: The canner is designed with safety features such as a pressure regulator and a locking lid, which ensure safe operation and prevent accidents.
  • Efficient sterilization: The Presto 23 quart canner is an excellent tool for sterilizing mushroom substrate, as it can reach and maintain high temperatures and pressures necessary for effective sterilization.
  • Durable: The canner is made from high-quality materials and is built to last, making it a worthwhile investment for any mushroom grower.
  • Easy to use: The canner comes with clear instructions and is easy to operate, making it perfect for both novice and experienced mushroom growers.
  • Cost-effective: The Presto 23 quart canner is an affordable option for mushroom growers looking for an efficient and reliable way to sterilize their substrate.
  • Consistent results: The use of a Presto 23 quart canner can result in consistent sterilization, ensuring that the mushroom cultivation process starts with a clean slate and that there are no unwanted microorganisms that could cause contamination or reduce the yield and quality of the final product.

Step 4. Inoculate

Allow the pressure cooker to depressurise naturally. Wait a minimum of 2 hours before removing the lid. Any sudden changes in temperature will result in broken grow bags.

The cooled substrate can be inoculated with grain spawn using aseptic technique. In the absence of a flow hood an enclosed space with minimal airflow should be used to undertake the grain spawn transfer.

oyster mushroom grain spawn

Aseptic Technique

It’s important to adhere to aseptic technique when inoculating sterile media. Sterilised media is extremely prone to contamination.

Only objects that have been flame sterilised may make contact with the sterile media or grain spawn.

Alcohol can be used to sanatise and clean surfaces of micro-particles but is not suitable for sterilisation.

A face mask should be worn at all times. All work should be undertaken with a laminar flow hood when possible. In the absence of a flow hood a smaller enclosed space with minimal airflow, such as a bathroom may be used with varied results.

agar plate for mycology

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