Should You Buy or Make Sterilized Grain?

1. Cost, per pound, of unprocessed grain: $ per pound
2. Value of your time: $ per hour
3. How many pounds of hydrated can you sterilize all at once?: pounds
4. Amount of Labor, in hours required to get, hydrate, bag, sterilize, and cool grain: hours
5. How much does 1 pound of grain weight once hydrated? pounds
6. How much do all of the Filter Patch Bags cost you? $

There are a lot of variables when it comes to deciding if you should make your own grain or buy it, so this calculator is only to help you understand one aspect of it, which is the cost. Not the convenience, noise, making your house smell like hot grain, etc.

It is undoubtedly good to have the skills of making your own and being overall more self sufficient and fault tolerant, as well as be able to do things precisely as desired.

However, sometimes it’s better to buy: we have some customers who purchase 320 bags (960lbs) per month. Obviously there is a real struggle with producing such a quantity at home without significant investments in a shop, the electrical wiring needed to operate several autoclaves or way more pressure cookers. Especially if these quantities are only needed intermittently or for a short period of time.


Other people simply hate grain prep, and don’t want their house smelling like hot grain as the pressure cooker hisses for 2 hours around their children.

Depending on quantities ordered prices range from $5.30/lbs down to $2.47/lbs with free shipping.

How to Make Your Own Grain Spawn

There are many different ways to prepare sterilized grain for mushroom spawn production, and there are many different grains that can be used, each requiring a different preparation.

Here is a tutorial on how to produce sterilized grain in a way that we feel is the easiest for home beginners that need small quantities. The initial startup cost is around $115 to $150, and can produce 7 pounds within a 2 to 3 hour period.

What you need:
1. 23 Quart Presto Pressure Cooker: $80
2. Grain: Anywhere from $5 to $50
3. Mason Jars: $10

To one jar, add:

250 grams grain. This can be birdseed (millet, sorghum, rye, oats, wheat, whatever)
200 to 250ml water. This quantity varies and will depend on how hydrated you want the grain and the type of grain you are using.

Add a lid, either one with an injection port and filter, filter only, or put the lid upside down so that it does not seal and can be opened later. Cover the lid and ring with aluminum foil.

Pressure Cook it. Be sure to allow the cooker to steam for a few minutes at boiling to remove all of the air inside as this will help it sterilize better. Once this is done, place the weight on top and allow it to reach 15 PSI. Once it reaches 15 PSI, start your clock and cook it for 90 to 120 minutes. then allow it to cool down. Do not open until it is at 0 PSI and the safety valve has dropped.

Shake each jar of grain to mix the grain around as the moisture may not be well distributed and it will also help loosen the grain, making it easier to mix later on.