Urban Spore

PF Tek

brf cake

What Is PF Tek?

The PF Tek is a technique that was originally developed to grow the psilocybin containing magic mushrooms (psilocybe cubensis) at home with common household items. Now it is often used for the cultivation of gourmet mushrooms such as oyster mushrooms. 

The PF Tek will teach you how to prepare and sterilise a nutrient dense jar of substrate consisting primarily of brown rice flour and vermiculite.

The sterilised substrate is subsequently inoculated with a liquid culture or spore syringe. Once the substrate has fully colonised it can be birthed and introduced into fruiting conditions.

Alternatively, the colonised jars of substrate can be used like grain spawn, ground up and mixed with a bulk substrate ready for fruiting.

colonised brf cakes

What Does PF Tek Mean?

PF Tek stands for “psilocybe fanaticus technique”. It was first released in 1992 at www.fanaticus.com. Although the PF tek was originally developed in order to facilitate the cultivation of psilocybe cubensis it is also a great way for beginners to begin working with sterilised substrates and spawn production.

Blue Oyster Mushrooms
Jumbo BRF Cake Formed In A Rectangle Deli Container

How Long Does The PF Tek Take?

There are a number of steps involved in the PF Tek. Although most of which require very little time the entire process can take between 3 – 4 weeks before mushrooms are ready to be harvested.

Preparing the substrate and jars may require approximately 1 hour. The substrate needs to be sterilised for a minimum of 1.5 hours and left to cool down overnight.

Inoculation of the sterilised substrate needs to be done as quickly as possible to avoid contamination and will require no more than 30 minutes – most of which will be dedicated to creating a clean workstation.

After inoculation it may take between 14 – 21 days for the substrate to finish colonising.

Once colonised the BRF cakes can be fruited directly from for quickest results or incorporated with a bulk substrate for larger yields.

What Is A BRF Cake?

A BRF cake is a block of substrate used for cultivating gourmet and medicinal mushrooms made from a mixture of brown rice flour, vermiculite and water.

brown rice flour for mushroom growing

What Is Vermiculite?

Vermiculite is a naturally occurring material that greatly expands when heated. It’s a great insulator, non-combustible, absorbent, compressible, odourless and inert.

Vermiculite is used in the PF Tek due to its absorbent qualities. It allows water, air and nutrients to effectively penetrate the substrate. Water retention and air flow are crucial for complete colonisation of the substrate.

Vermiculite can be purchased here. 

vermiculite for mushroom growing

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What You'll Need?

In this guide we prepare sufficient substrate to 3/4 fill 6 mason jars. The PF Tek can be measured as a ratio of 2:1:1. 2 parts vermiculite: 1 part brown rice flour: 1 part water. In this guide we will be using mason jars to measure quanitites.

Step 1. Prepare The Jars

We will be using wide mouth mason jars to ensure that the cake can be removed easily without damage once fully colonised. Modified lids are required for growing mycelium in jars. These lids feature both a filter for fresh air exchange and an injection port to allow for the injection of liquid culture with minimal risk of contamination.

These jars can be made with with syringe filters & rubber injection ports or micropore tape & RTV silicone depending on the resources available. Alternatively they can be purchased here. 

Learn more about making modified lids in the link below.

Modified Mason Jar Lids

Modified mason jar lids make the production of mushroom grain spawn and liquid culture a breeze.

Each lid features a filter patch for fresh air exchange and reusable injection ports for easy inoculation with a liquid culture syringe.

Step 2. Prepare BRF Cake Mix

Incorporate the brown rice flour and vermiculite before adding 3/4 of the water. Slowly add the remainder to  ensure that the substrate isn’t over saturated.

Ideally the moisture content within the substrate mixture will reach ‘field capacity’. When the substrate is squeezed firmly in your fist it should  clump together without excess water dripping from it. 

Dry substrates will either colonise slowly or incompletely. Over saturated substrates will not colonise and potentially harbour contaminants.

brf cakes

Step 3. Pack & Seal Jars

Fill each jar with the BRF cake mixture using a spoon. The jars should only be 1/2 – 3/4 full. Take care not to apply pressure as we don’t want to compress the BRF cake mixture. A light, fluffy cake will breathe better and ensure a faster, more complete colonisation. 

(Optional) Apply a  shallow layer of dry vermiculite over the top of the BRF mixture. This nutrient sparse layer of vermiculite will assist in protecting the nutrient dense substrate from contamination.

Place lids on the jars and cover with a layer of aluminium foil. Press firmly around the rim to ensure that it creates a tight seal.

Step 4. Sterilise

Place the sealed jars in a pressure cooker. We recommend lining the pressure cooker with towelling to reduce the movement and possibility of broken glassware. Add water ensuring that the water level is no higher than halfway up the jars.

An electric bench top pressure cooker or instapot can be used for this project. Although electric pressure cookers generally will not reach the recommended 15 PSI the jars are small enough for the heat to fully penetrate and destroy all potential contaminants.

Sterilise for a minimum of 90 minutes at 15PSI. Allow the pressure cooker to depressurise and cool down completely before opening. 

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Step 5. Inoculate

Once the jars have cooled down they are ready to be inoculated with either a liquid culture or spore syringe.

The sterilised substrate is highly nutritious and susceptible to contamination. For this reason it is important to inoculate using aseptic technique.

If possible a flow hood should be used. Alternatively, you can undertake inoculations in a enclosed space with minimal airflow, such as a bathroom. 

Prepare the work space and syringe before removing the layer of aluminium foil. Using an open flame sterilise the needle and inject a few CCs of liquid culture or spore syringe in each of the 4 holes in the lid. Promptly cover each hole with micro-pore tape. Flame sterilise the syringe between each jar.

Note: We strongly recommend the use of liquid culture over that of a spore syringe. Spore syringes can often contain contaminants which will grow faster than the spores can germinate. Whereas liquid culture is a serum containing viable mycelium and will colonise with greater vigour.

Step 6. Birth The Cakes

Once the BRF cakes are fully colonised they can be birthed from the jars. Take care to not damage the outer protective layer of mycelium. The cakes can now be placed into a fruiting chamber. 

colonised brf cakes

Step 7. Dunk & Roll

The birthed BRF cakes may have dehydrated during the last 2 weeks while the mycelium has been growing. The BRF cakes can be submerged in cold clean water for up to 24 hours before being rolled in clean vermiculite.

The BRF cakes will float when placed in water. We recommend using a clean container with a lid to keep the BRF cakes completely submerged. 

(Optional) Depending on local water quality you may wish to boil & cool the water before use to ensure that it is free from unwanted contaminants.

Additionally, the vermiculate can be baked 160 degrees Celsius for 1 hour to reduce risk of contamination. Alternatively, 1 jar of dry vermiculite can be cooked in the pressure cooker. This is usually not required when using new bags of vermiculate.

Step 8. Store In Fruiting Conditions

Mushrooms require humidity to grow. We recommend using a mini-greenhouse or similiar. Spraying the inside walls of the greenhouse will help raise humidity. A cheap humidifier can used to automate the process.

Alternatively you can build a Shotgun Fruiting Chamber (SGFC) using a plastic container with holes drilled in all sides and lined with dampened perlite. The increased surface area of the perlite increases the rate of evaporation therefore increasing humidity.

Shotgun Fruiting Chamber

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Step 8. Harvest

Over the next 3 – 14 days the BRF cakes will begin to form primordia or pins. These small formations will grow into mushrooms within a few days. Once mature they can be harvested making way for the next flush. I recommend removing the fruiting bodies using a sharp knife as to not damage the BRF cake. 

The following flush will occur naturally within the next 7 – 14 days if the BRF cake is left in fruiting conditions.

Note: These time frames will vary depending on the species being cultivated.

chestnut mushrooms

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