Grain for Simple Minds



These instructions will guide you through the process of preparing grain either to be used as spawn to inoculate bulk substrates or as mushroom substrate that can be directly cased.

Basic rye recipe for 1 pint jar:

- 100g (=3.5 oz~125 ml~0.53 cup) rye
- 110g (= 3.9 oz =110 ml~0.46 cup) water
- knife tip full of gypsum

Basic millet or birdseed recipe for 1 pint jar:

- 100g (3.5 oz~140 ml~0.59cup) birdseed
- 80g
(2.8 oz = 80 ml~0.34cup) water
- knife tip full of gypsum

If you are going to prepare rye for producing spawn, you might use a tad less water( I use 105g in that case)

1/4 qt(quart) = ˝pt(pint) = 1cp(cup) = 236ml(milliliter) = 236cc(cubic centimeter)

The cups, pints and quarts are in the US liquid measuring system.

Fill both the measured amount of grain and the water into the jar, screw the lid fitted with a polyfill filter tight and pressure cook for 1 hour at 15 psi.

The water absorption ability can vary depending on the grain quality and the type and the size of the pressure cooker.

It´s best to make a batch of test jars when one acquires a new grain for instance 100g rye and 100, 105, 110, 115 and 120g water.
Then you´ll see which water content provides the best result.

rye kernels

millet based birdseed


Immediately after the pressure has settled, take the still burning hot jars from the cooker using a towel and shake them well to mix the wetter and drier kernels.

rye after pressure cooking

If you turn the jar upside down, you can see the drier kernels separate from the wet kernels at the bottom.

rye jar upside down

After shaking the grains should appear wet, after a few days after inoculation they will loose this look and look more drier.

Put the jars back in to the pressure cooker and let sit until cool.

It has to be pointed out that the grain on this picture was meant to be directly cased after colonisation.


rye shaken

The grain used for spawn should look a bit drier, but still moist, and have less exploded kernels. The rye on this picture has been pressure cooked 48 hours ago with a rye/water ratio of 100g/105g.

Preparing rye grain by simmering - TEST RESULTS

(originaly posted at the Shroomery)

I decided to test a rye grain for the water absorbing ability.

I weigted out 3 time 100 gram rye grain.

1. 100 g rye were dried in the oven at 140°C for 90 minutes
2. 100 g rye were simmered in 500 ml of water for 30 minutes (rye grain put in boiling water)
3. 100 g rye were simmered in 500 ml of water for 40 minutes (rye grain put in boiling water)

1. The 100 g rye grain in the oven dried to 88 g -> 12% moisture content.
2. After 20 minutes of draining the grain weighted 190 g, nearly no exploded kernels ->(12g+90g)/190g = 54% moisture content
3. After 20 minutes of draining the grain weighted 200 g, more exploded kernels, I´d say at the limit ->(12g+100g)/200g = 56% moisture content

Preparing grain by simmering it is a viable option. It shows that the amounts usually used when one mixes grain and water directly (100g grain and 100g-110g water) are similar(a little higher) as if one simmers the grain for around 40 minutes.

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