How to Make Culture Slants

Introduction

This tutorial will guide you through the process of making culture slants for mushroom growing. Culture slants are essential for preserving mycelium cultures, allowing you to store them for up to a year or more. They provide a compact, nutrient-rich environment that slows down mycelium growth while allowing for easy access when you need to make transfers.

Step 1: Gather Your Materials

Before starting, ensure you have the following items:

• Centrifuge tubes: 15 milliliters (or larger if preferred)
• Pint-sized jar: To hold your culture slants during sterilization
• Plastic lid: For the jar during pressure cooking
• Syringe: 10 or 12 milliliters for injecting agar into the tubes
• Needle tips: 18-gauge (blunt or pointy)
• Scale: For measuring ingredients
• Malt extract agar: For your slants
• Food coloring: Optional, for aesthetics
• Sticks: Craft or popsicle sticks (optional, useful for extraction)
• Boiling water: For rehydrating sticks

Step 2: Prepare the Sticks

If using sticks for your slants:

1. Cut the sticks to fit inside the centrifuge tubes.
2. Boil the sticks in water for about 10-15 minutes to rehydrate them.

Step 3: Prepare the Agar Mixture

1. Measure the ingredients needed for the agar solution:
   • For 144 milliliters of solution:
     • 4.3 grams of malt extract
     • 2.8 grams of agar
2. In a half-pint jar, mix the agar with about 150 milliliters of boiling water to dissolve it effectively.
3. Stir the mixture well to ensure even distribution of ingredients.

Step 4: Fill the Culture Slants

1. Add the rehydrated sticks into each centrifuge tube.
2. Using the syringe, inject approximately 6 milliliters of the agar solution into each tube.
3. Optionally, add a few drops of food coloring for aesthetics (note that this may cause some mess).
4. Ensure to leave the caps of the tubes slightly loose to allow steam to enter during sterilization.

Step 5: Sterilize the Slants

1. Place the filled tubes in your pint jar with a bit of water at the bottom to create steam during the pressure cooking process.
2. Tighten the lid of the jar loosely.
3. Pressure cook the jars for 25 minutes at 15 psi.
4. Allow the pressure cooker to depressurize naturally, which may take about 30 minutes.

Step 6: Create the Slant

1. Once cooled, remove the jars from the pressure cooker using gloves to avoid burns.
2. Tighten the lids on the culture slants to prevent contamination.
3. Tilt the centrifuge tubes to create a slanted surface for the agar to increase the area for mycelium colonization.

Step 7: Storage

1. Let the slants cool to room temperature.
2. Store unused slants in the pint jar with a sealed lid at room temperature.
3. Once you start using them, transfer any colonized cultures to the refrigerator for longer preservation, ideally checking and making transfers at least once a year.

Conclusion

By following these steps, you can successfully create your own culture slants for mushroom growing. This method not only preserves your mycelium cultures but also provides a reliable way to work with your favorite mushroom strains over time. Feel free to reach out with any questions or join the community for support in your mushroom growing journey!