How to Make Perfect Grain Spawn Every Time
Grain is the most common material used when making mushroom spawn. Grain is an nutritionally dense food source and provides exceptional moisture retention. It is also cheap, versatile, easy to make and is readily available. For these reasons, when growing mushrooms at home, grain is hands-down the best spawn substrate you can use. If you don’t want to buy pre-made grain spawn, than this article is for you. In this post will discuss how to make perfect grain spawn every time.
For this example we will be using Rye, but there are many other seed/grains that you can use with great success. Alternatives include wheat grain, brown rice, wild birdseed, and popcorn. Each grain has its own unique properties with regard to moisture retention. So, its best to play around with this process when using other grains.
Rye, AKA Rye Berries, is a cheap and available grain. The key to success when using Rye comes down to preparation, ideal moisture content, and proper sterilization.
Steps to Make Perfect Grain Spawn
Step 1: Rinse the grains, then soak in water for 12-24 hours.
Step 2: Steep the grains for 15-20 minutes.
Step 3: Drain and set out to dry to remove any excess moisture from the outside of the grains.
Step 4: Load grain into mason jars or mushroom spawn bags and sterilize for 90-120 minutes at 15 PSI.
Materials You Will Need
- Grain (rye berries) – Click this link for an organic option free of fungicides
- 5 Gallon Bucket or large container
- Stove and large pot.
- Mesh strainer, screen, or mesh brewers bag.
- Mason jars and poly-fill or filter disc, or micro-pore tape – OR – Myco Bags.
- Pressure cooker.
This method of preparation requires a little more work than other methods. But with this method you will make perfect grain spawn every-time.
Step 1) Rinse and Soak
The first step to making grain spawn is to measure out the desired amount of grain. When using rye, it is important to understand that once hydrated the grain will expand to twice its size.
A good rule of thumb is to use one quart of dry grain for every 3 quart jars of finished hydrated grain spawn.
When buying your grain from a feed store, it will likely be full of dust, wood chips, and other debris. Before using it you will want to rinse it a couple times until the water runs clean. This is easy to do by pouring the grain in a bucket and draining over a strainer.
Once your grain is clean you will place it in to a 5 gallon bucket or large pot for soaking. You may choose to add additives such as gypsum, coffee or other ingredients.
Fill the bucket with water submerging the grain with at least 2-4 inches of water above the grain line.
A helpful water to grain ratio for perfect rye spawn is as follows:
- 200g Rye Berries (1 cup)
- 220ml Distilled Water
This ratio will make one quart jar. Adjust according to your needs.
Set the grains aside to soak for 12-24 hours. This process serves two purposes. First, a soak will allow the grains to absorb some water, making them less likely to split when simmered. And second, this process “awakens” dormant organisms, making them easier to kill during sterilization.
STEP 2: Simmer the Grain
Simmering the grains is when the real hydration happens. A short cook of the grain softens them up and forces them to swell and absorb water.
Pour the grains from your bucket in to a large cooking pot. Add water until there is at least 2″ of water above the top of the grain. Place the pot on the stove top on high heat. Bring the grains to a boil, then reduce the heat to medium/medium high for 10-15 minutes.
Be careful not to cook them for too long. Over cooking can cause the grain to split. A perfect grain will be plump and uniform in color. No white will be visible on the inside of the grain.
STEP 3: Drain and Dry the Grain
Timing is pretty important during this step. You will want to drain the water and lay the grain on a screen as quickly as possible. This will allow the grain to dry via steam/evaporation. Allow the grain to dry for 1-3 hours, or until there is no visible moisture on the grain. You will know they are ready if you place a paper towel on the grain and none of the kernels stick.
The grains should now appear swollen and dry. A juicy contradiction…
STEP 4: Pack and sterilize
Now we will load our dry, hydrated grain into our jars or myco bags.
Using Jars:
When using jars, make sure to only fill them to 2/3-3/4 of their capacity.
You will need to modify the jar lids by drilling holes for a breathable filter and injection port if needed. There are different ways of modifying your lid. We find it most effective to drill a single 1/4″ hole off-center on your lid. You may then use polyfill, tyvek paper, or synthetic filter disks for the filter.
With regard to the injection port, there are many different options available. So you will need to measure the seated diameter and drill another hole to that size. These peel-and-stick injection ports are easy to use and highly recommended.
Finally, cut a sheet of tin foil and use it to wrap the jar lid before sterilization. This prevents moisture from entering the jar and messing with the moisture content.
Using Myco Bags:
When filling your myco-bag, make sure to leave 2-3 inches of space between the top of the grain and the filter patch. This allows space for the gasses to build up and escape through the filter.
Once filled to the desired amount, fold the bag opening over and around the grain like a burrito. I like to use masking tape to hold the top of the bag in place.
Sterilization:
IMPORTANT: Make sure your pressure cooker has enough water in it. I have ruined plenty of Presto 23s by overlooking this simple principal.
Load your pressure cooker with your grain spawn containers. Make sure to leave enough room so that the safety valves on the lid of your Pressure Cooker are free and clear.
Bring the pressure to 15 PSI and set a timer for 90-120 minutes. The elevation where you live will affect this, at higher elevations I would lean on the longer side.
And there you have it, perfect grain spawn ready for inoculation using spore syringes or culture.
