What the Heck is PF tek?
The Comprehensive Guide
This is the comprehensive PF tek guide, meant to provide the beginner with all the information they will ever need regarding PF Tek.
If you have experience or are looking for a quick start, you can read the refresher Quick Start guide here!
PF tek is by far one of the most popular methods used for the cultivation of mushrooms. It’s an absolute must know for anyone starting out with the hobby as it has quite a high success rate and very low level of difficulty. Even if you don’t start out with this technique you will probably come back to use it at some point.
The PF tech is a beginner friendly tek as it does not utilise any costly equipment and all materials are readily available, it’s the perfect tek to start with to develop good sterilisation and cleanliness protocols. This is good advice as the low cost of the PF tek means that even if you do make a mistake (which we all do ofcourse- how else would we learn!) it’s not going to be costing you a lot of time or money!
Most people that begin a mycology hobby will start by using the PF Tek due to its ease of use, and the fact that it makes use of readily available equipment that you are likely to have at home already!
Quick Summary of the PF Tek for Growing mushrooms:
- PF Tek uses Brown Rice Flour (BRF) to create cakes of BRF and vermiculite
- The BRF and vermiculite mixture is loaded into specially prepare jars
- Jars are sterilised with a pressure cooker
- The mycelium is inoculated into these cakes
- When ready, the cakes are removed from jars and kept in fruiting chambers
- Fruiting conditions are created and maintained
- A flush of mushrooms appears, which are then harvested
- Dunking of cakes by submerging in water for 12 hours
- Cakes are returned to fruiting conditions to allow for a subsequent flushes
- PF Tek stands for Psylocybe Fanaticus Technique
- It was developed by Robert McPherson in the early 90’s
You can see from the name that this technique was developed with varieties of the psylocybe mushroom in mind. However it has quickly become adopted by cultivators of all types of medical and gourmet mushrooms- for example delicious and nutritious Oyster Mushrooms have been shown to grow effectively using this method!
Before starting with the PF Tek it is worthwhile considering some of the Pros and Cons of this technique
All equipment easily accessible and inexpensive
Relatively low contamination rate
Can be modified (eg PF Tek + Bulk Substrate)
Takes less space than using multiple shotgun or monotubs
There aren’t many con’s when it comes to the PF Tek, however the one gripe that cultivators may have with this method is its low yield,
Only suitable for use with a spore syringe/culture
This low yield is especially noticeable when you start to compare the process to Teks that make use of bulk substrates.
However, the advantage of this method is that you can still achieve relatively good yields without having to prepare bulk substrates, which can easily contaminate all of your inoculated jars if not prepared correctly ( and nothing hurts more than emptying tubs of contaminated substrate into your compost bins after checking your jars each night during inoculation for two weeks).
Jars – ‘Bell Wide Mouth’ preserving jars 240ml
Brown rice flour (can be made with brown rice and a spice grinder)
Micropore / hypafix tape (adhesive breathable medical tape)
Notes on equipment
These jars will be the home to your BRF cakes. Importantly they will need to be sterilised by placing them in a pressure cooker so they need to be able to tolerate the heat, usually anything marketed as a preserving jar will fit the bill.
Some of the most popular jars used by hobbyist are the ‘Bell Wide Mouth’ preserving jars 240ml.
The wide mouth feature is essential no matter what brand you go with: the cakes will need to be removed from the jar once they are inoculated, and if the mouth is narrow, there is no way they will come out in one piece, meaning you will have to break your cakes apart.
Additionally make sure your jars have the rubber seal on the inside of the lid, this is important for controlling gas exchange and preventing contamination, again anything marked as a preserving jar will have this.
Another thing to note is that we will be drilling holes into the lid! This so we can insert the spore syringe and allow gas exchange. The Bell Jars do sell lids separately, so you can always get more if you think you might use the jars for something else in the future.
While the Bell Wide mouth jars are popular, there are no issues with using 300ml preserving jars from Kmart at $5 Aud for 6 which are about a ¼ of the price of the Bell jars. The only thing I have noticed using these jars is that the lids will rust where you drill the hole if you do not dry them properly after use- but at only $5 for a half dozen it almost doesn’t matter!
Regarding size, People have been able to inoculate huge jars of *** size. However it’s important to consider that by doing this it is going to take a looooong time to fully inoculate the jar, also you will need a lot more liquid culture. Something around the 240ml size will allow for speedy inoculation.
Additionally using larger jars creates a larger risk of the jar simply stalling, or for contamination.
Brown Rice Flour
Brown Rice flour will be what provides our mushrooms with all the nutrients that they need to grow, so it’s not negotiable in this tek! If you live somewhere that brown rice flour is readily available, that is awesome, but sometimes that is not the case!
Usually you can find it at health food shops, or places that specialise in organic food etc.
One thing you will notice though is that it can be quite expensive, way more expensive than just brown rice.
If you want to save money, or simply cannot find any BFR, you can really easily make your own.
Simply grab some long grain brown rice from your supermarket and add it to an electric coffee grinder or similar food processor device and grind it to a fine powder.
Usually not all of the rice will be pulverised, just grind as much as you can in small batches and put it through a sieve to remove any large pieces of rice that didn’t break down.
Step by Step Guide for completing the PF TEK
Step One- Preparing the Jars!
The very first step of the process will be to prepare the jars for the PF- Tek. Once you have the jars prepared you will be able to use them again and again for this tek and many others!
Before you start make sure your jars meet these two requirements:
- Have a wide mouth
- Don’t explode in the pressure cooker (place them in without their lids for 10 mins at 121 to check)
Now the fist step is to make 2-4 holes in the top of the lids
- Using the smallest drill bit you can find, make 4 holes approximately 10mm from the outer edge of the lid- space them opposing each other.
- Alternatively use a nail and hammer to punch 4 small holes
- Alternatively use a heated sharp object to push 4 small holes.
- The smaller the hole the better, the larger hole will simply create a larger portal for potential contamination during inoculation. As long as a spore syringe can fit through, the holes will be big enough.
You will often see alternative options including using one central hole in the center of the lid, or using 2 holes opposing each other. Four holes will allow quicker inoculation, so stick with it!
Now these jars are ready to go for our purposes! If you are interested in making some jars that have self healing injection ports, you can read more about that here, but for now these jars will do!
Step two- Prepare the cakes!
The BRF cakes are amazingly simple to make. They require only three ingredients.
- Brown Rice Flour
These are always mixed in a ratio of 2:1:1, or:
2 parts vermiculite, 1 part BRF, 1 part water
In your clean mixing bowl, start by adding two cups of vermiculite
Add one cup of water and mix thoroughly
Add one cup of BRF and mix thoroughly
To make sure that your BRF mixture has the right consistency and water content, pick up a handful and squeeze it firmly in your hand. If a few drops of water come out, perfect, it’s ready to go! If your hand is overflowing with water when you squeeze, more than a teaspoon of water comes out, then you have too much water and need to add some more vermiculite. If nothing comes out, then you need to add more water.
This water content is known as field capacity and is essential for the cultivation of mushrooms. As a general rule you will run into a lot more problems having too much water than too little.
Step Three- Add mixture to jars
Add your freshly made BRF mixture to your jars, filling them roughly ¾ of the way.
Fill the remaining space in each jar with dry vermiculite.
Screw on your lid for each jar
Step Four- Prepare jars for Sterilisation
Your jars are nearly ready to be placed into the pressure cooker, but there are two things to do first:
Cut 4 small pieces of tape for each jar
Apply small piece of tape over each hole
Apply square piece of foil over each jar lid
The medical tape is designed to be permeable to gas but not organisms. This means that it will allow for gas exchange which the mycelium will require ( This is why we have four holes in our lids), but at the same time will limit our risk of contamination.
Usually one layer of tape is enough, if you have had trouble with contamination or want to be extra safe, you can apply more than one layer. The type of type you use will also play a factor, I use hypafix as it comes in a large roll and is relatively cheap.
The main purpose of the foil will be to stop water from entering our jar through those holes we have created. This would ruin that perfect vermiculite, brf, water ratio that you created earlier.
Step five- Sterilisation of your jars!
The original PF tek made use of a large saucepan with a tight fitting lid instead of a pressure cooker, however over the years hobbyists have come to find that the rate of success can be greatly increased by using a pressure cooker instead.
The process that we are using is steam sterilisation which utilises pressure and steam to sterilise our jars. It’s the same process that is used in Autoclaves used for medical equipment at hospitals and dental surgeries etc.
It should be noted that you can still achieve fine results using a large pot if you do not have access to a pressure cooker, however if there is one piece of equipment you should invest in for your hobby, the pressure cooker would be it
Note: electronic modern instant pot/ pressure cookers are not recommended, instead you want a traditional style pressure cooker that can reach 15 PSI
If you are using a pot opposed to a pressure cooker, ensure that it has a tight fitting lid! This tight fitting lid will allow pressure to build inside the pot, remember we are steam sterilising, which needs two components, pressure and steam! As we cannot achieve the same pressure using a pot as we can using a pressure cooker, we will need to sterilise the jars for longer, 90-120 mins is recommended.
Make sure you follow your pressure cookers instructions at each stage, if it’s your first time using the pressure cooker it would be recommended to try a practice run before putting your BRF cakes on the line.
Place your trivent in the bottom of the pressure cooker to lift your jars from the bottom, ( rings can also be used here) if you can keep your jars above the water level, this is best.
Add 1-1.5 inches of water
Its best to bring the pressure cooker up to pressure gradually over 15 mins
One at pressure (steam is rapid escaping), reduced heat to allow for a mild consistent stream of steam from the pressure cooker
Cook for 60mins at 15 psi
Leave to cool for at least 1 hour and remove jars
Make sure you never put a sealed jar with no holes in your pressure cooker.
Place your trivet or jar rings/ spare lid on the bottom of the pot
Add water to the top of the trivet
Add aluminium foil over the trivet
Add your jars on top of foil.
Place your lid on top of your pot
Set heat to high and bring water to a boil
Once at a boil, reduce heat and let simmer for 120 minutes
Boil a kettle of spare water
KEEP AN EYE ON THE WATER LEVEL, as you do not have the tight seal of the pressure cooker you will lose a lot more water as steam, if you manage to run out of water during the process it is a quick way to ruin your pot!
Make sure you are adding water throughout the 120 minutes to ensure that the pot never boils dry
Remove the Jars and allow to cool min 1 hr.
Inoculation is where you will be inserting the spores that are currently in the spore syringe into the BRF cakes that you have made.
The original PF tek does not make use of a still air box. However this would be greatly advised to minimise the risk of contamination. Additionally having a still air box is good practice for many methods in mycology such as working with agar, and you will definitely get good use out of having one.
For information on how to make a suitable still air box and how to prepare your work surface- click here
Prepare your work surface by wiping with alcohol. Alternatively set up your still air box and place your jars inside, ensuring the outside of jars have also been wiped.
To minimise contamination, wipe the outside surface of the jars including aluminum foil with alcohol prior to working
Take you spore syringe and shake to distribute the spores and break up any clumps that have formed
Follow sterile technique to apply the needle to your syringe
Light your bunsen burner or oil lamp. Alternatively, have your lighter nearby
Starting with one jar, remove the aluminium foil, placing it upside down on a cleaned area within the SAB,
Peel back the tape over one hole,
Insert the needle of your syringe and inject the solution ( you will be injecting around 1ml per jar, so aim to inject 1/4ml per hole if you are using 4 inoculation holes per jar)
Aim the solution towards the glass of the jar (aim to the outside, not the centre of the cake)
The needle is usually inserted past the dry vermiculite layer, but this can depend on the length of the needle. It is very possible to hold the needle above the verm layer and shoot the solution down the side of the glass also.
Remove the needle and reapply the tape to the hole
Repeat for the remaining 3 holes – there is no need to reapply the foil
Once one jar has been completed, hold the needle over the flame until red hot, then allow to cool for 30 sec before starting the next jar.
Although the process is tedious, performing one jar at a time, one hole at a time, minimises the risk of contamination by reducing the length of time that the entry portal to the jar is open.
If you are using a brand new needle out of the package you do not need to flame sterilise for the first jar (provided you haven’t touched the needle accidentally)
Incubation and watching the mycelium grow
By this stage, nearly all of the hard work is done! All that is left to do is place the jars in a suitable environment to allow the mycelium to fully colonise the jars. It is usually possible to find a suitable place within your house without requiring any special equipment for the incubation period. If you happen to live somewhere that does face extreme temperatures ( and you don’t use heating and cooling in your house) then you may benefit from using an incubator. However this will not be required for most growers.
Suitable locations require the following features:
Kept in the dark and out of direct sunlight
Between 20- 27 degrees celsius
Clean and dry environment
Common locations include wardrobes, spare cupboards, a nice shelf etc.
Ideally it will be somewhere that does not receive a lot of traffic eg your main pantry- as this will increase the chance of contamination. You may also place them in a large container, however remember that the jars will need air flow for the mycelium to grow.
Higher temperature will increase the speed that your mycelium will colonise your jars, however will also increase the risk of contamination. Keep between 21-27 degrees is optimal.
Over the next 1-3 weeks the mycelium will slowly colonise the jars, you will see this as a gradual white growth.
Once your jars are visibly fully colonised (the jar is fully white and there is no visible cake showing) it is best to wait one more week to ensure that the centre of the jar is fully colonised too before birthing of the jars, this will further reduce the risk of contamination.
Routinely check your jars for any signs of contamination ( See here for example) and remove any contaminated jars as quickly as possible.
Do not open the jars at any time during colonisation.
Becoming a proud parent and birthing your Cakes!
Once your cakes have been left to colonise an additional week from when the outer layer is fully covered with mycelium it is time to birth the cakes.
Remove the lid from your jars
Turn upside down and tip out the top vermiculite layer, you no longer need this, so empty into the garbage or your garden
Gently tap out your cakes, ensure that you do not break the cakes. They should slide out relatively easily as they will actually be reduced in volume during the colonisation period as a significant amount of water content from the cake is consumed.
Rinse off any remaining vermiculite under running water
Place cakes in a container, fill with room water temperature, apply lid and leave submerged in a dark, cool area for a minimum of 12 hrs, no longer than 24 hours.
After the 12-24hrs is up fill a container with vermiculite
One at a time, place the cakes in the dry vermiculite and roll around to cover the cakes in a thin layer of vermiculite. It can be very difficult to get the vermiculite to stick, however just try to get the best coverage you can. This step can even be disregarded completely however it commonly used to create better fruiting conditions and achieve better yields
Time to place in the fruiting chamber
Now it’s time to place your cakes in a fruiting chamber. This can range from greenhouses, to a bucket with a clear lid, even an aquarium. The original PF tek utilizes a simple clear storage container, and you can definitely stick with this.
The key factor is that you are trying to create an environment that will cause the mycelium to fruit.
A great item to consider making is a shotgun fruiting chamber – they are relatively easy to make and do not require any specialist equipment, just a few modifications to a large container with the added benefit of great fresh air exchange.
Learn to make a shotgun fruiting chamber here.
For this PF Tek we will be using a large plastic storage container (64 L), although a SGFC is is a later adaption you can look into.
Start by rinsing your perlite to remove dust,
Once the perlite is dampened. Apply a layer of perlite approx 20-30mm thick to the bottom layer of the storage container
Cut a square of alfoil for each cake to sit on, wipe these with alcohol and place in the container where the cakes will sit, try to space them at least 5cm apart to accommodate room for the growing fruits.
Place a cake on each square of alfoil.
Place the lid on the container and leave the container in a location that gets a small amount of light ( but not any direct sunlight)
It’s important that you do not have a tight fitting lid as fresh air exchange is essential for the fruiting of the mycelium and its growth. If your container has an airtight lid you will need to place the lid upside down over the top or adjust it to create a small gap either side of the container.
Maintain fruiting conditions
Misting and fanning are the two methods that are commonly used to create and maintain fruiting conditions.
If you are using the large container method:
Remove the lid and mist the cakes using a very fine mister, if you are unable to use a fine mister, use a regular mister but aim away from the cakes, ensure that water does not pool on the alfoil at the base of the cakes.
Then fan the cakes for 2-3mins to induce evaporation on the surface of the cakes
Repeat this process 2-4 times a day
If your cakes are already quite wet ( you can see fine droplets of water on the surface of the cakes, or you can see the verm layer glistening in the light, you can skip misting)
If you have dunked and rolled the cakes, and have the layer of perlite in the bottom of the container, it’s very unlikely they will dry out even if you do not mist them for a couple of days.
The process remains the same for the SGFC, however the fanning component is not required as more than enough fresh air exchange will occur if the chamber has been constructed correctly. Sometimes to induce pinning faster, a grower may start a cycle of misting and fanning, in order to create evaporation which is a large trigger for fruiting, however this should still occur without the need to vigorously fan multiple times a day.
You should start to see pins within a week!
Once you have pins the mushrooms will start to grow fast, and you will have to know when to harvest what is known as the flush. This will be determined entirely by the species of mushroom you are trying to cultivate. For Oyster mushrooms this is just as the cap is starting to take on a flattened appearance.
For most mushrooms it is usually when they are most potent which is right before the veil breaks and just before the mushroom drops its spores.
Usually when you are ready to harvest you will have a variety of mushroom sizes, most will be just about to break their veil, some may have already. There will also be some which have stopped growing, and remain very small, these are known as aborts and are found in most species, generally these will be darker in colour.
When you harvest your flush should harvest all the fruits, including the aborts, which you can usually still use despite their small size!! Leaving them on can lead to contamination during your subsequent flushes.
Harvesting the fruits can be achieved by gently twisting the mushroom at the base to remove it from the mycelium, or by using a clean exacto knife to cut the fruit as close to the mycelium as possible. The goal is to try and leave the mycelium as intact as possible for the next flush and reduce the risk of contamination.
What next? Keep going!
Repeat the dunking and rolling method, this time aim for a full dunk of 24 hr before placing the cakes back into the fruiting chamber
The remainder of the process remains the same
The process can be repeated until the cakes eventually become contaminated- it’s important to remember only so many nutrients are present within the cake, and the life cycle of the mycelium is only finite. However, from the fruits of the mushrooms we can gain spores, allowing us to repeat the cycle indefinitely