Grains lose a lot more moisture during colonizing than you might think.  If youve ever made a GLC, youve probably noticed that you suck less water out than you put in.
Citric suggests rehydrating the grains prior to spawning and I tested this out recently.

I find that:

Colonization times for bulk substrate decrease, sometimes by as much as 50%+.
Fruits are thicker and healthier.
Yields are slightly improved.

There is no added contam risk for a properly pasteurized substrate and fully colonized grain spawn.

Also note that you cannot rehydrate spawn that has not lost a lot of moisture. If you have quickly-colonizing grains (under one week), odds are they will not benefit much from a dunk.

How to do it the quick way:

I take a roll of fiberglass screen (the kind used in window screens) and cut a piece to fit around the top of a five gallon bucket.

Grab the five gallon bucket and clean it out. 

Break up your spawn jars and give each a good smell to make sure it is clean.

Dump the contents of each clean jar into the bucket and fill with enough cold water (not distilled) to cover the grains.


Attach the house screen with a rubber band and let it soak for 10 to 20 minutes.


When the time is up, secure the screen with your hand around the edges and tilt until the water pours out. It will drain very quickly, tapering down to a small stream after 10-20 seconds.


Spawn the grains to your substrate as usual.



How to do it the other way:

Break up your grain jars as usual. Open each one and give it a good smell to make sure it is clean. Then fill each jar with cold water (not distilled)
Let it soak for 10 to 20 minutes.


Drain by placing the lid over the top and leaving a gap between the lip of the jar and your lid. Drain it well. The grains will be quite wet at this point.

Spawn the grains to your sub as usual.

A properly pasteurized substrate and clean grain spawn are as contam resistant as it gets, so this dunk can be done with minimal precautions- as long as your grains are fully colonized and substrate properly pasteurized.

If you are using a sterilized substrate, you will need to dunk under aseptic conditions and with sterilized water as well. Do not dunk your grains before G2G.

Some mycelium is lost to the water, but you will see almost no visible myc in the water as long as you dont agitate them while they are soaking.

A commonly asked question is if there is any use for the dunk water after the dunk. While the myc-laden water could be called a grain LC, it needs to be kept clean if it is going to be any use. So if you are using sterile water and working in a still-air box or hood, then in theory you could use the dunk water as a GLC. I would not recommend it though

If you want to make a GLC with the dunk water:

Additional steps need to be taken. Here is a brief outline of the process:

Sterilize a jar of water with a filter + inoc port on the lid.
Work inside a SAB / in front of a flowhood. Use good sterile technique.
Make sure the water is room temp. Use a sterile syringe and needle to move water from one jar to the other.
Flame sterilize the needle between each transfer.
Let the grains soak for 10-20 minutes.
Then shake it up a little and suck the water out of the grain jar and push it into the jar of water.
GLC complete.
Drain the rest of the water off from the grains in open air and they are good to spawn


This is particularly beneficial for species that remain in-jar for long periods of time, such as sclerotia producers. Mycomattie shows the difference between dunked and not dunked tampanensis fruits:

mycomattie said:

Dunked on the left - sloooow (not dunked) on the right.... P. tampanensis

DUNKED for 15 minutes in 1 quart jar with cold tap water.





NOT dunked and just crumbled and cased

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FrankHorrigan said:

So I took a bag of grains that had been colonized with an isolate.

I removed one grain before dunking the rest.

I also took a dunked grain of the same size.

I put the two on agar to see just how much the mycelium benefits from being rehydrated before spawning to bulk.

Here is the timeline, today I realized this would be a good thread of its own:

8/27 (24 hours after being placed on the dish):


8/29


8/30


8/31


Here is the not-dunked side vs dunked:


9/1

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Please post results and feel free to discuss and ask questions too


edit: added info from discussion. added pics.

UKBen said:

Holy shit!! Is it normal for that many to flush?!

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MushroomNSwiss said:

Why not just make your sub a little bit moister? Then you aren't dumping myc down the drain.

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zMan said:

You aren't washing away almost any myc. You break up the jars and there is little agitation when you add water to dumping so the myc really doesn't have a reason to come out that quick in such a short dunk.

When I did it all that came out was a bit of yellow water not anything that looked like myc.

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Were you surprised by how much water was absorbed?

FrankHorrigan said:

zMan said:

You aren't washing away almost any myc. You break up the jars and there is little agitation when you add water to dumping so the myc really doesn't have a reason to come out that quick in such a short dunk.

When I did it all that came out was a bit of yellow water not anything that looked like myc.

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Were you surprised by how much water was absorbed?

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