This is a cheap and relatively easy way I've come up with to use BRF half-pints to inoculate grain by turning the colonized BRF into a liquid slurry that is then poured into quart jars of whole grain. I had seen the blade assemblies of some brands of household blenders used in this context before with colonized petri dishes, and I tried it as an alternative to the very expensive autoclavable blenders sold for this purpose. I didn't expect the incredible results I got from using a BRF jar instead of a petri dish as the source of mycelium, and after some refinements to the initial design I've come up with one that provides consistent results, is extremely durable, simple to make, and cheap.
Although the procedures themselves are fairly simple, this probably qualifies as an intermediate or advanced tek. It's not a good choice for a first grow and I've made some assumptions in these instructions, namely that the reader has grown mushrooms before and is familiar and experienced with the PF Tek, growing on whole grain, and creating proper fruiting conditions, none of which are covered here.
Here's a summary of how it works:
- Choose a good looking half-pint BRF jar colonized with the species/strain of your choice. I recommend a lighter, bare-bones BRF recipe that allows for the quickest colonization times (I use about 1/4 cup of rice flour and a pinch of corn meal per half pint). I usually only fill the jars slightly over halfway with substrate so the dry vermiculite contaminant barrier is very thick. Think of it as a three dimensional petri dish.
- In front of a flow hood, dump the cake out of the jar and cut off the upper portion just in case it harbors a contaminant.
- Drop chunk of colonized BRF cake into sterilized mason jar containing about 200 ml of water, using a blender blade assembly as the lid (tighten the band firmly!).
- Blend until it's a uniform slurry, usually takes several 3-5 second bursts.
- Switch blades for lid with dispenser nozzle.
- Pour slurry into grain jars.
- Shake jars as vigorously as you can for about 20 seconds each (a long time, in other words).
- When fully colonized (95% colonized works too), shake them again the night before spawning to bulk or casing the grain. The following morning they should show significant recovery if the temps are correct, otherwise suspect a bad batch.
There are two ways to use this as described: Colonizing jars of grain extremely quickly or inoculating a large number of jars from a very small amount of spawn. So far I've only been interested in setting speed records for quart jars, and my fastest time so far was a quart half-filled with 100% cracked corn that fully colonized in 56 hours (though I don't use cracked corn anymore for various reasons).
- Regular mouth mason jar (pint size)
- Blade assembly (including gasket) that fits regular mouth mason jars.
- Autoclavable plastic lids or regular metal lids, either will work but I prefer the plastic ones (and they are worth every penny)
- 1/2" hose barb X 1/2" FIP threaded brass adapter
- 1/2" MIP thread X 3/8" FIP thread brass hex bushing
- 1-1/8" O.D. X 23/32" I.D. rubber grommet
- Teflon tape
- Silicone sealant (any type that works for an airport)
- Double-sided tape
- Aluminum foil
- Two crescent wrenches that can open to 7/8"
- Small bit for pilot hole (~1/8" is fine)
- 5/8" countersink bit (this was $9 at the Big Box store, but worth it)
- ~ 3/4" tapered abrasive grinding bit
- scrap wood as backer for drilling
The Blender Blade Assembly:
This is the easiest part. Get a blender with a blade assembly that is the same diameter as a regular mouth mason jar (approx. 2.5 inches or 65 mm). Oster brand blenders have several models of this size, and if you already have a blender or want to make several mason jar blenders, the cheapest source for just the blades and gasket is here ($6.99 each).
By itself, the gasket tends to get tangled up in the blades, which was a problem I tried numerous ways to solve.
The simplest and most effective solution was just sticking the gasket on with some double-sided tape. Use four pieces of tape to stick the gasket to the base, then trim off any extra tape around the outer edge. It doesn't hold very tightly, but it's only there to add just enough adhesion to avoid the entanglement problem. DO NOT use silicone or anything else to attach the metal band to the blade assembly. I discovered the hard way that the band must be loose or you cannot tighten the lid enough to prevent leaking.
The Dispenser Nozzle:
Here's a photo of the parts needed for the dispenser nozzle. I will show one being made with both a metal and a plastic lid.
These are the tools, and I've already marked the center of the lid. The hammer and nail are just for punching a little dent where you want the hole so the drill bit doesn't wander across the lid.
Drill out a pilot hole, using some scrap wood as a backer.
With the 5/8" countersink bit, expand the hole until the bit passes all the way through. This can be tricky at first, so use light pressure and medium RPM to get the hang of it. Be careful not to crimp the lid anywhere or it won't work well and makes a mess later. The bit works well in wood, metal, or plastic.
Now expand the hole further with the abrasive bit. This also takes a little practice to get good at, and I suggest holding the lid in one hand and rolling your wrist so no part of the bit gets a rut dug into it by the metal. Hold the drill firmly at max RPM with your other hand. It's not hard to make a nearly perfect hole if you're patient, and have a few practice sessions. This bit also works on plastic (watch out for it clogging up with plastic, a stiff brush can clean it off).
This is the step that requires the most patience. Still using the abrasive bit, keep shaving off material a little at a time and then test the grommet to see if it fits. It should be easy to attach it to either type of lid, and it's ok if the hole gets a little too big. When the grommet spins freely in the hole, it's big enough. Ideally, to fit the threaded brass fitting through the grommet, you should have to screw it in. The brass threads will cut into the rubber as you twist, and so long as it'll fit through far enough to attach the nozzle it's fine.
This is the view from the bottom and side. You want the threads oriented this way or it won't work.
Now wrap the threads with Teflon tape. This makes it much easier to take it apart later if necessary.
Using the wrenches, tighten the barb fitting (the nozzle) onto the taped threads. As the barb screws on, the grommet will compress a little, so you can tighten it further than it appears and the fittings can handle a lot of force, so don't be shy when you tighten it. Watch your knuckles!
Clean the lids really well, then seal the fittings and grommet to the lid with silicone (seal both sides of lid). Let cure at least 24 hours.
The finished dispenser lids.
Continued in the next post...