How to maximize efficiency by soaking Millet for spawn prep.

**Large cereal grains aren't great choices for soak prep as they require boiling to properly hydrate the larger kernel.**
Soaking for too long will cause the soak water to ferment which is an issue on it's own:
Why fermentation sucksThe following is a test of my previous statement, this test was done with wheat but will apply to oats, rye, etc:
Wheat is an excellent grain, it holds a great deal of moisture but requires boiling to truly hydrate this large kernel. The following picture is a side by side comparison of completely raw unhydrated wheat next to the same wheat that has been cold soaked for exactly 24 hours:

The column on the left is the 24 hour soak, the right column is raw. Not much difference visually on the exterior, let's cut them open to view the inside:

As you can see the starchy white core has not been affected much by the soak but it has absorbed a small amount of water for sure.
The following picture serves to illustrate the obvious difference in size between the 24 hour soak and some wheat that was properly hydrated via a 20 min boil:

As you can see there is a significant difference in colour and size.
Now time to cut the boiled grain open to view the interior side by side:

There is now a very obvious difference between the boiled grain on the left, and the soaked grain on the right. The soaked grain has a veneer of hydration surrounding the white starchy core while the boiled grain has a clear center and is fully/properly hydrated.
Although I believe its possible to grow on soaked wheat or other large cereal grains, the soak method does not fully hydrate the kernel.
Due to the density of the larger cereal grains like wheat, oats, rye, etc, the core needs to be fully hydrated to efficiently transfer the energy required to properly sterilize the grain. Improper hydration could result in incomplete sterilization; proper water content in the grain increases conductivity.
Now onto millet: What is Millet? I soak millet (my preferred grain) overnight for 18 hours because it's convenient for my sterilization and inoculation schedule. I don't soak any longer because you run the risk of germinating the seeds.
I soak in 5 gal buckets with cold water. Should you desire to soak hundreds of pounds at once I recommend a stock tank with drainage plumbed into the bottom using a large volume brew Hop filter strainer for kettle or mash tun to prevent seeds from clogging up the plumbing:

I've made the switch from wheat to soaked millet as my preferred grain due to the heat and energy required to boil/hydrate larger cereal grains; I find this method convenient for preparing large quantities of grain with minimal effort:
• No need to bring large quantities of water to a boil;
• No need for lengthy drying times;
• No excess heat or steam.
I believe millet (and other seeds) are the best grains for bulk production for this reason: less energy expenditure for more inoculation points.
The reason I choose to soak as apposed to "no prep" method (adding dry grains to jars or bags and then adding water to hydrate during the sterilization cycle) is because I find the grains come out of the pc partially hydrated in some spots while others are overhydrated/cooked into a clump at the bottom of the jars or bags.
If you do attempt to no prep, I recommend rinsing the grain clean first. This will help to some degree with clumping but more importantly preps your grains for efficient energy transfer to the surface of your grains instead of the dirt.
Millet soaking in 5 gal buckets:

How it looks post soak:


Quote:
cronicr said:
I couldn't pin point my issue with my coir last year until a couple moths ago, even left over bucket tek coir was going bad on me , couldn't figure it out for the life of me and just awhile back while cleaning I grabbed my bucket for coir and while rinsing it out spotted a big G on the bottom lol.
at some point I switched buckets and had been prepping my bricks in my grain soak buckets filled with starch
Quote:
Pastywhyte said:
This is something I never remember to mention. I have dedicated buckets and pots for everything. I have a huge aluminum pot that has never had anything but water in it. Cross contamination includes nutrient dense media residue.
Pro tip:
Make sure to keep dedicated grain soak/prep buckets separate from your coir prep buckets, just incase.
When prepping grains in buckets/pots before sterilization you'll deposit starches, etc, from the grains to the interior surfaces of the bucket or pot; if you mix your substrate in a bucket covered in starches and tiny bits of grain debris this will add highly nutritious non sterile material to your coir/verm which will cause it to rapidly mold after spawning; you can cross contaminate your coir if your buckets/pots are used interchangeably.
Cross contamination from prep utensils that have come into contact with unsterilized/hydrated grains like buckets, pots, spoons etc can and will happen if you're not paying attention.
Prior to soaking I highly recommend washing/rinsing your grains until the runoff water runs clear, even if the runoff is clear immediately give it a few rinses anyways, I get bacteria in my spawn if I fail to thoroughly rinse my grains.
Failure to wash off the filth and dirt will mean that your sterilizer will have to penetrate this overburden as well as sterilize the surface of your grains which reduces the efficiency of your cycle.
Failure to rinse/wash prior to soaking will hasten fermentation, you'll notice a very yeasty odor and bubbling.
How things turn out when I don't rinse:



How it turns out when I rinse:




Note on rinsing/washing grains:
Washing grains serves primarily to remove the dirt and debris that will impede the autoclaves ability to penetrate the load effectively and efficiently; but will also likely remove a large population of endospores that are comingled.
The addition of a touch of dish soap would obviously assist with cleaning but will act as a wetting agent/surfactant that will wet all surfaces of the grains, wettimg the grains will help to ensure efficient energy transfer to the grains surface.
After soaking I allow the millet to drain for 20 mins or so while I work on other things, after a quick drain the millet is still pretty wet to the touch:
• load 3 full quarts (12 cups) per bag which is roughly 4 myco quarts.
(1 bag= 1 tub)
This brings my bags to just over the 4lb mark; using 4 full quarts (16 cups) makes a 5+lb bag which I find takes up too much space in the PC;
• If doing jars I load 2 8oz scoops/jar
(4 jars= 1 tub)


• I then sterilize in my 75x for between 3.5 and 4 hours @ between 17 and 20psi;
• If doing jars in a 23 quart presto, pc for 2- 2.5 hours.
I've recently verified the 90 minute cycle to be sufficient for grain jars but less is not more with sterility assurance.
Flash Prep:
Should you not want to soak prep your millet for whatever reason, flash prep is an old school wbs method that can be adapted for millet:
The original flash prep teks:
Foo Man's WBS Method
Reverse FooMan WBS Prep: Ziran
30 mins works best for millet otherwise the result will be too many burst grains/starch, the excess starch will cause your jars to solidify into a solid mass:

too many burst grains after 1 hour in boiled water.
Note:
The reason that millet (WBS, etc) can be loaded wet is because they're small, hard seeds, any excess surface moisture is going to be absorbed either during the cycle or within the first few days after inoculation; Seeds haven't had water already boiled into them in the same way that larger grains like wheat, rye, or oats do, This will happen in the pressure cooker.
Don't be concerned if your seed comes out of the PC damp, your jars/bags will sort themselves out by absorbing the excess moisture. Jars soak up moisture in a few days, bags are gtg after a good shake;

Post shake:
Notice how the seeds are clinging to the sides? This is normal, things will sort themselves out in a few days; just give the filter a tap with your finger to dislodge any grains that will be stuck up in the GE hole of your lid.



You'll notice that some grains will look darker than others, some will even burst, this is all fine. Things will look perfect once mixed.
How they look when colonized:



My bag prep method:
If you look closely you can see that my method for closing the bags is a wrap around (unsealed) as apposed to an accordion fold, both work equally well. I'll add pics or even a short video when I do my next run in a few days.
How I run my bags in the 75x:
How I run bags in Presto:
Mycelium runs well:



And fruits well:



Here is a fully colonized, healthy bag of millet spawn:

Both of these pictures are from the same bag: the pic on the left is the top of the block with the bag removed. You can see that some of the top grains look uncolonized, this is not the case and it is worth noting as it is a common occurrence with bags. Filthyknees has a thread dedicated to this topic:
Will dried grains topping spawn bags lead to contaminationThe picture on the right is a shot from the side of the block with the bag peeled away to show a clear view of the underlying spawn. That portion in the middle that appears to also be uncolonized is where I put my thumb into the grain, lol.
A word on millet bags from 🦄
A word or two on sterilization times: