PF Tek

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This tek is best suited for beginners as it has the least amount of preparation, yet it can produce enough mushrooms for any cultivator and a few friends to have a great time. The PF Tek uses brown rice flour and vermiculite, which are readily available and inexpensive, to form a substrate, known as cakes, that can be sterilized, inoculated and colonized in the same jar and then can be fruited when placed directly into a fruiting chamber.


In the early 1990’s Robert McPherson (Professor Fanaticus) developed a method to propagate mushrooms using half pint wide mouth mason jars, brown rice flour, and vermiculite. This method is referred to as the “PF-TEK”.


This method allows a person to fruit the cakes directly, without having to mix with anything else, add substrate, or further incubate after initial colonization is complete.

For each jar you will need 1/8c Brown Rice Flour (some recipes call for 1/4c per jar but we find the original recipe best) ½ c Vermiculite 1/4c Water

It is recommended that noobie growers order a viable spore syringe from a reputable vendor.


1. Measure out the vermiculite into a large bowl.

2. Add the right amount of BRF to the bowl. (INSERT PF TEK CALCULATOR)

3. Measure the water, and slowly add it to the brf/verm mix, stirring slowly while adding the water.

Note: Do not be tempted to add more water than the recipe calls for. DO NOT ADD EXTRA WATER.

4. Stir, stir, stir , then stir some more.

5. Stir even more.

6. Fill jars with brf/verm mixture, filling the jar up to the bottom of where the ring will set, or about where the threads end at the top of the jar.

7. Fill the rest of the jar with plain vermiculite.

8. Place lids on right side up, or the way you would normally put the lid on the jar for canning (not upside down). Screw the ring on the jar lid until it is on all the way, without adding extra pressure to screw the lid down.

9. (OPTIONAL BUT RECOMMENDED) Put one piece of micropore tape over each inoculation hole.

10. Cover the jar lid tightly with foil.


Unlike grain, which requires a pressure cooker or autoclave to prepare, PF-TEK can be sterilized using Tyndallization (Fractional Sterilization), which requires only a pot of boiling water. (NOTE: Using a pressure cooker is always recommended over Tyndallization )

While preparing brf cakes does not require the use of a pressure cooker, it is highly recommended that you use one to sterilize your jars.

Pressure Cooker Method

1. Place the recommended amount of water into the pressure cooker. Most cookers require no more than 2” of water.

2. Set your jars in the pressure cooker. Feel free to stack jars on top of each other, or lay jars on their sides on the top of the bottom layer of jars. Jar lids should not come into direct contact with the water in the bottom of your pressure cooker.

3. Put the lid on the pressure cooker and set the burner on medium for the first fifteen minutes. This allows jars to slowly warm, and will help avoid cracking or breaking the glass jars.

4. Turn the heat up to high, and let the pressure cooker heat up until the gauge reads 15psi.

5.Pressure cook the jars at 15psi for 45 minutes. If the pressure cooker does not have a gauge, start the timer when the rocker starts to rock like crazy.

6. After 45 minutes at 15psi, turn the burner off and set the cooker off of the burner. Let the pressure cooker depressurize on its own, do not release the pressure manually or try to speed up the cooling process. When the pressure reaches zero psi, open the pressure cooker lid so that moisture can steam off of the jar lids while they are still warm.

7. Allow jars to cool completely before inoculation.


1. Prepare work area in advance. See (insert link for tips on preparing for clean work)

2. Remove the foil from the jar lids and set aside for later use.

3. Dab inoculation holes that are covered with micropore tape with an alcohol soaked cotton ball.

3. Flame sterilize the spore syringe needle until it is glowing hot by using a lighter or other flame source such as an alcohol lamp, then place an alcohol soaked swab over the needle to cool it, and cover it while you move the needle to the first inoculation hole of your jar.

4. Carefully insert the syringe into the first inoculation hole making sure the needle goes beyond the top verm layer. Then dispense 1/4cc into each inoculation hole. Place the foil you sat aside back on the jar loosely. Flame sterilize the needle between each jar, and repeat the process.


In general it is a good idea to place inoculated jars in a clean, dark , tub of their own during colonization. Opaque Rubbermaids are ideal. Jars will colonize at room temperature but incubation at 74-80F is recommended for faster results.

Check out some our tried and true methods for incubation on our incubation teks.

Check on your jars every few days to ensure they are healthy. If you are keeping them in a tub of their own you will be able to notice any odd smells that may be an indicator of contamination as you open the incubator. (INSERT LINK TO NOTES ON CONTAMINATION)

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