STEP 3. Let’s prepare first substrate for magic mushrooms. Recipes and cooking time for different types of grain. Moisture level and useful additives for mushroom spawn

How to cook grain substrate for mushroom spawn
Step 3. How to make grain substrate for mushroom spawn

STEP 3. Day 1-2. How to cook grain substrate for magic mushrooms

On the previous Step 2. Types of substrates and Choose grain for spawn you've already chosen right grain and calculated the necessary volume. Now it's time to prepare substrate for spawn.

Let's get started!

What you need for grain substrate preparation

1️⃣ Whole grain from listed below. You'll find recipe for each one further

Hard Red Winter Wheat Berries, 3 lbs - $13.95

Whole Oat Grain Seeds (With Husk Intact), 2/5/10 Lb $12.99

Rye Berries, 5 lbs $21.95

Unhulled Barley (Hull Intact), 12 Lbs $31.99

Whole Grain Sorghum, 24 Ounce $9.99

Brown Rice 5 lb $19.99

Millet Grain, 3 lb $16.99

2️⃣ Optional! Hydrogen peroxide solution 3% (H2O2) or any antibiotic in pills (chloramphenicol or analogue)

Hydrogen Peroxide 3%, 32 oz $9.50

3️⃣ Gypsum or Calcium Sulfate (CaSO4)

Garden Gypsum Fertilizer, 6-Pound $12.71

Organic Garden Gypsum Calcium Sulfate, 5 lb $17.55

4️⃣ Vermiculite

Vermiculite 8 qt. $14.60

Organic Vermiculite 8 qt. $15.39

5️⃣ Teaspoon and tablespoon

6️⃣ Pot with lid

7️⃣ Sieve or colander

Rinse and soak grain for spawn

This step can be applied for unhulled grain: wheat, oat, rye, barley, bird seeds, corn.

❗️Skip this step for hulled millet and brown rice (we'll discuss it later)

1️⃣ Rinse the grain (wheat, oat, rye, barley, corn, unhulled millet) thoroughly 2-3 times in cold tap water to get rid of dust, husks, dead bugs etc. until the water is pouring off reasonably clear

Pre-cooking substrate for growing Psilocybe Cubensis
Preliminary preparation of whole grain for substrate for growing psilocybin mushrooms

2️⃣ Pour water in clean grain (tap water or clean drinking water). Add 1 leave it to soak for 12-24 hours at room temperature, about 60-80F or +15C..+25C. No problem if you leave it to soak even for 48 hours.

Soak grain for mushroom spawn before simmer
Soak grain for mushroom spawn (24 hours) before simmer (wheat berry)
Soaking whole oats for mushroom spawn
Soaking whole oats for mushroom spawn
Why it is necessary to soak grain for spawn

❗️Skip this step for hulled millet and brown rice

It is optional, but I highly recommend step! Why?

First of all, grain is saturated with the necessary moisture and cooks faster.

Now the most important reason. As you know bacteria multiply by simple cell division. To do that they need water. During soaking in water bacteria and their endospores inside grain are activated, they sprout. To kill bacteria and endospores when they are woken up will be much easier and more effective.

And here we are with pressure cooker and sterilization!

After 12-48 hours of soaking you can feel a yeasty, sweet and sour smell, notice some fermentation bubbles.

DIY substrate for mushroom spawn
Fermentation bubbles appear after 24 hours of soaking

Don't worry, this is normal and great state to rid them off by simmer the substrate and Step 5. Sterilization

How to prevent grain substrate from sticking

Add a little bit of gypsum to grain substrate. It is optional, but it helps to prevent the grains from sticking together. For 2-3Qt of DRY grain add about one tablespoon of gypsum powder. You can add it while cooking the substrate or while soaking the grain. I prefer to add gypsum when cook the grain, after soaking

Shroomok's choice on Amazon:

Garden Gypsum Fertilizer, 6-Pound $16.60

Organic Garden Gypsum Calcium Sulfate, 5 lb $21.38

Additional grain substrate disinfection

Optional step to prevent bacteria contamination, however antibiotics don't prevent mold contamination

1️⃣ Rinse grain after soaking 2-3 times in clean water.

2️⃣ For an extra antibacterial effect add antibiotic pill before boiling the grain. You can use hydrogen peroxide 3% solution (H2O2) instead. Antibiotic or H2O2 help to get rid bacteria off.

If you use H2O2 : add 8 oz (230-250 ml) per 1 Quart (1 Liter) of grain and 1 Quart (1 Liter) of water.

If you use antibiotic (chloramphenicol or any analogue) add it in the following proportion: 1 pill/capsule (500 mg) per 1 Qt of grain and 1 Qt of water.

The dosage of the pill/capsule is indicated on the blister

Antibiotic Chloramfenicol for substrate for growing psilocybin mushrooms
Antibiotic Chloramfenicol for substrate

3️⃣ Grind a pill and turn it into powder. If you use antibiotic in capsules just open the capsule

Grinding antibiotic for substrate for cultivation Psilocybe Cubensis mushrooms
Grinding antibiotic for substrate for cultivation Psilocybe Cubensis mushrooms

4️⃣ Pour about 1Qt of clean drinking water into 1Qt of grain

Add clean water (1 liter) to the grain
Add clean water to the grain

5️⃣ Add antibiotic powder (500 mg) or hydrogen peroxide (8oz or 230-250 ml)

Adding antibiotic for preparing substrate
Adding antibiotic for preparing substrate

6️⃣ Mix thoroughly so that the antibiotic or hydrogen peroxide is distributed evenly

Stir substrate with antibiotic
Stir substrate with antibiotic or hydrogen peroxide

7️⃣ Ready for cooking!

How to cook grain substrate for mushroom spawn

1️⃣ Put a pot with water and grain on the stove. Bring to a boil over maximum heat (or maximum power)

Start to boil grain for substrate
Start to boil grain for substrate

2️⃣ Turn down the heat and continue to simmer. Count down the time from this moment!

How long to simmer grain for mushroom substrate

Cooking time of grain depends not only on the type of cereals, but also on the quality, variety, place of growth, storage conditions. Countdown the time since water started to boil:

⏰ Wheat, barley, rye — about 25-35 min

⏰ Oats, millet — about 10-15 min

⏰ Brown Rice — about 15-20 min

⏰ Corn, popcorn — about 45-55 min

Boil wheat about 25-35 min, oats for 10-20 min
Boil grain to prepare substrate

🔴 Make sure grain don't turn into mush! Such grain should not be used. Subsequently, it will become sour and will be taken over by bacteria or mold. Better to have a little bit undercooked grains

Examples of wrong grain substrate preparation

Boiled too long = too much water = too little air = bacteria contamination = trash

Here is an example of too wet overcooked grain that quickly goes sour and bacteria contamination appear. Slime appear at the bottom

Too wet substrate for psilocybin mushrooms cultivation. Psilocybe cultivation problems
Tenderized over boiled substrate for psilocybin mushrooms cultivation. Psilocybe cultivation problems

🔴 Too uncooked grain is also bad! Then the grain will not get enough moisture and the mycelium will be weak, grow poorly or not grow at all

Not enough moisture = weak growth of mycelium or no growth at all = trash

Here is an example of too dry grain substrate

Too dry substrate example for magic mushrooms cultivation. Psilocybe cultivation problems
Very dry substrate for psilocybin mushrooms cultivation. Psilocybe cultivation problems
Ideal cooked grain for mushroom spawn

The grain should be springy, but soft :)

Wheat after boiling. Preparation substrate for growing psilocybin mushrooms
Wheat after boiling. Substrate preparation for magic mushroom spawn

In general, if you see the first grains start to burst, it's a sign to stop boiling.

Ready grain for mushroom growing (wheat berry). Single grains are opened

One more tip to check:

💡 Take a single grain, press it with your fingers, it should open easy. Grain is ready!

Grain should remain moderately dense and maintain the integrity of its shell. Such level of cooking should be for any type of grain: wheat, oats, barley, rye, rice, bird seeds, sorghum, millet, corn, etc.

3️⃣ When grain is ready drain the water

Drain water from wheat (or oats) after boiling
Drain water from grain after boiling

4️⃣ Rinse thoroughly in clean cold water

Rinse grain for substrate for magic mushrooms under running water. Substrate preparation for growing psilocybin mushrooms
Rinse grain for substrate under running water

5️⃣ Throw ready grain into a sieve (or colander) to remove excess water

Put the substrate to grainer
Put the substrate to sieve
Leave grain in strainer for 30 minutes. How to prepare substrate for growing psilocybin mushrooms Psilocybe Cubensis
Move grain into the sieve

6️⃣ Leave the grain in this way for 30-40 minutes, so that excess water comes out. After boiling 1 Qt of DRY grain turns into about 1.2-1.4 Qt of cooked grain

Ready grain for preparation substrate for growing magic mushrooms
Leave grain in sieve for 30-40 minutes
Perfect grain for mushrooms. Let it sit for in sieve for 30 mins

You can spread the grain on a towel in a thin layer and it will absorb the excess moisture, it will be faster. I don't do this.

How to determine if the grain is dry enough. Take a hand full of grain and put it on a paper towel. If the grain does not leave obvious wet prints on the napkin — it's dry enough!

7️⃣ Move grain from the sieve back into the pot.

Optional! Add 2-3 table spoons of vermiculite if grains are still too wet or you have about 20% of opened grains

Add vermiculite (or perlite) to substrate
Add vermiculite (or perlite) to make grain substrate

❗️I usually add vermiculite to wheat berries and brown rice. For other types of grain (corn, millet, sorghum, oat, rye) don't use vermiculite!

Vermiculite works as a drainage for wet wheat or brown rice, helps to avoid clumping and sticking. It allows good regulation of substrate moisture. If the grain is too wet, it will absorb excess moisture. If the grain loses moisture and becomes dry, vermiculite will give back absorbed moisture to the grain

Shroomok's Choice on Amazon:

Vermiculite 8 qt. - $13.90

Organic Vermiculite 8 qt. - $15.39

🔴 Substrate must crumble in hands, be moist, but NOT WET and NOT DRY! You'll find your optimum with experience. Just take a grain in hand. If you feel it is moist, but there are no drops of water, then it's perfect state

8️⃣ Mix thoroughly to have an even mass. As a result, substrate should look like this

Substrate with added vermiculite (or perlite)
Stir substrate with vermiculite (or perlite)

How to prepare Brown Rice grain for mushroom substrate or 10-10-15 method

I'd like to quote great tips and recipe by belle☽ — our fungi fairy of Shroomok Growers Community on Discord:

For anyone struggling with Brown Rice, I use the 10, 10, 15 method.

I let my water reach a boil on high heat for 10 minutes.

Then I turn it to medium heat and let my rice boil for the next 10 minutes.

After that I drain my rice and rinse with cold water and let it chill for 15 minutes before inserting into my jars.


Shroomok's Choice on Amazon:

Brown Rice 5 lb $19.99

How to prepare Brown Rice Flour aka BRF substrate for mushroom growing

It's super simple recipe for beginners. You always have right moisture level here.

Just mix 2 cups of vermiculite and 1 cup of brown rice flour.

Then add 1 cup of water.

BRF substrate for mushroom growing
BRF substrate for mushroom growing

Stir it thoroughly to have even mass.

Prepare as much BRF substrate as you need, just use the right ratio (vermiculite 2 parts, brown rice flour 1 part, water 1 part).

💡 You can grind brown rice in coffee grinder to get brown rice flour or use ready brown rice flour, up to you


Shroomok's Choice on Amazon:

Vermiculite 8 qt. $14.56

Brown Rice Flour 3 lbs $13.99 - ready flour for BRF substrate

Long Grain Brown Rice, 5 lb $19.99 - grind in coffee grinder to make a flour any time

Coffee Grinder w/Cleaning Brush, Stainless Steel, Different Designs $20.95 - for grain, mushrooms, making microdosing capsules

How to prepare Hulled Millet for mushroom spawn

Yes, you can use hulled millet, it's not a mistake. It is one the easiest way to prepare substrate for mushrooms.

No wash. No soak. No simmer

Just pour hot boiling water in grain. Fill completely to cover the millet (about 1 inch from the top of grain or 2 cm). Close the pot with lid and leave millet for 20-30 minutes to soak.

Drain the water with millet through the sieve.

No need to dry the grain on towels or wait for all excess water to drain. The water will continue to soak in during sterilization process in pressure cooker.

I'd like to note about vermiculite for millet. Vermiculite is a cool absorbent for wheat or brown rice, however it dries the millet very much. Don't add vermiculite to millet substrate!

Shroomok's Choice on Amazon:

Hulled millet, 3 lb $16.99

Ready sterilized grain for spawn on Amazon

You can buy ready for inoculation sterile grain for mushroom spawn and skip this and the next few steps.

If you have ready sterile grain move on Step 6. Inoculation

Such option can save your time greatly and money for expensive pressure cooker, jars and lids accessories, even grain. It's a great option if you want to try mushroom cultivation with ease.

Shroomok's choice on Amazon:

Sterilized Milo Grain Bag, 3 Lb - 1 Bag 14.95

Sterilized Rye Berry Substrate - 1/6/12 Bag - $16.50

Sterilized Wheat Grain Bag, 3 Lb - 1 Bag - $16.88

Sterilized Rye Grain, Quart Jar - 1 Jar - $17.99

Sterilized Rye Grain Substrate - 2 Jars - $29.56

Sterilized Rye Berry, 3 lbs - 2 Bags Each 1.5 lb - $35.47

Sterilized Rye Berries, 1 Pound - 6 Bags - $46.50

Sterilized BRF Jars Brown Rice Flour Substrate - 6 Jars - $58.00

Sterilized Rye Berry, Quart Jars - 4 Jars - $59.95

However I suggest to handle the whole process by your own. It will be cost effective for long term mushroom cultivation hobby

What to do next

At this point our grain substrate is ready for Step 5. Grain substrate sterilization

But we need right Jars or Bags for it. Let's make one more step — STEP 4. DIY Jars and Bags for grain substrate

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