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How Much Water Does Grain Absorb?

It’s been a slow few weeks on the planet Earth. Corona has locked down just about everything, wherever you’re reading this from, I hope you’re safe and well.

This week, the question popped back in my mind about how much water grains absorbed prior to sterilising them. This information could come in handy if you were to ever do the ‘no simmer tek’ whereby you simply hydrate and sterilise your grains without simmering them. The idea being, with the correct volume of water in the vessel you avoid having to ‘double handle’ the grains.

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I could just weigh out some grain, hydrate it and weigh it after to see how much water the grain had absorbed. I did this initially but then thought that I could improve on this. I asked myself ‘which is the way you can cram the most moisture into your grain without bursting it?’ I gathered what I think are the 3 most common grains used in light commercial and hobby tier mushroom growing. Rye, Wheat and Wild Bird Seed, I suspect the result would be the same for those using any cereal grain. I put together three categories of technique;

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Different Types Of Grain Spawn For Mushroom Growing | Mushroom Blogs | Mushroom Growing | Mushroom Tips | Mushroom Business
Different Types Of Grain Spawn For Mushroom Growing | Mushroom Blogs | Mushroom Growing | Mushroom Tips | Mushroom Business

I suspect the result would be the same for those using any cereal grain. I put together three categories of technique;

Soak & Simmer

The process of soaking grain for 24 hours in water before simmering it for 10 to 20 minutes.

Simmer Only

The process of simmering it for 20 to 30 minutes.

Soak Only

The process of simply soaking the grain for 24 hours.

I gathered 9 pots together, each of them with 3 portions of 50g of Wheat, Rye and Bird Seed.  I hydrated 2 of the 3 pots in 400ml of water for 24 hours.

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I started by simmering the ‘Simmer Only’ Grains for 25 minutes, Next, I simmered the ‘Soak and Simmer’ Grains for 25 minutes. 

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With the hydrate only grains I did nothing except drain them for 15 minutes on a sieve to remove any water piggybacking on them. I allowed the grains that had been simmered to steam dry for the same reason.

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From the picture you can see the difference in weight. Bearing in mind they all started at 50g dry. You can see a much more detailed table below!

How Much Water Does Grain Absorb? | Mushroom Growing | Mushroom Blogs | Mushroom Growing | Mushroom Tips | Mushroom Business

From this ‘so called experiment’ I now don’t see a point in soaking the grains in water for 24 hours before simmering them. For the small fraction of extra hydration, the grains absorb, it seems unnecessary to give myself an extra step. Of course, it is up to you how you prepare your grain, the time and energy saved by simply hydrating and sterilising your grain may offset the possibility of slightly under-performing grain spawn. I hope this experiment helped other people asking the same questions about grain spawn. Any questions feel free to fire away!

Cheers!

This Post Has 2 Comments
  1. Is there an ideal hydration for grains (in bag) when inoculating?? I have always used the kitchen paper test where you pat the grains with kitchen towel to see whether is pick up any moisture. But if i knew what percentage hydration the grains should be at – in theory, i could leave them on the kitchen scales until enough water has evaporated from them and they are the correct weight before filling up my bags.

    Love your website

    Moose
    Wales

    1. Hi Moose!

      I’m sure some of the bigger mushroom producers have an exact percentage but for our purposes, ‘as full without bursting the grain’ is what we aim for. Most commercial strains are tenacious so will thrive on most levels of hydration, other than dry obviously!

      Just make sure they’re not saturated when you put them in your bags, otherwise the water will pool at the bottom, not ideal! I wouldn’t get too scientific, I have tried that approach and it’s not yielded anything more! One of the biggest improvements for me was to add a bit of wheat bran to my grain spawn, that seems to really help the growth and trains the mycelium a bit to develop the correct enzymes for the substrate!

      Thanks for the comment Moose, I appreciate it!

      Any questions, don’t hesitate to contact me!

      Cheers!

      Gareth

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