Using Your Straw Pellets as a substrate.
Hydrate the straw pellets.
You want to hydrate the pellets until they hold the water you have provided, but do not drip water unless lightly squeezed. This amount per pound of pellets varies because of many factors including how long your pellets have been stored, the storage location, local humidity, altitude, and more.
It is then best to play with the amount of water you add to your straw pellets. Many people find the ideal amount of water is 2X or more of the weight of the straw pellets.
If you have a scale reset the scale for the weight of your plastic mixing bucket.
Add 1.5lbs of pellets and 3lbs of water. Let it rest and soak up the water.
Return to the bucket and mix the straw and water to share the hydration evenly.
Straw is very absorbent. It takes on its full amount of water content but does not gain as much mass as Coco Coir for example.
While we are talking about Coco Coir, it is worth mentioning that for some Mushrooms people like to use a 50-50 amount of Coco Coir to Straw Pellets. Some feel it makes a great substrate. Especially for certain types of mushrooms.
Pasteurize your Straw Pellets
Take your hydrated straw substrate to about 180 for 2 hours. Less if you are using a pressure cooker or sterilizer.
Let the substrate cool then squeeze out any excess water.
Add your grain spawn when the substrate has cooled with a 10% mixture of grain spawn to straw log, or bag. If you are using Coco Coir in the 50-50 blend, you may go as low as 8% but solid results will still be obtained at 10%.