[Tastebridge] Oyster Mushroom Status?

Roger H domitron at yahoo.com
Wed Oct 19 19:18:30 UTC 2011

I hate to be the bearer of bad news, but in my experience, the uncooked bags just starting to show colonization on top will almost certainly not completely colonize in the near future.  The reason the top colonized in the bacterially-contaminated bags is because the bacteria cannot tolerate the drier top surface thus the mycelium has an initial advantage there.  The bacteria blooming within the supplemented grounds, though, will prevent the core from colonizing and eventually either kill or halt all mycelium in the bag.  The mycelium, if it can hold on, might have a chance later to resume colonization but that chance would be months, not days, from now, enough time for the grounds to compost basically.  In the meanwhile, the stench of rotting Spawn Mate proteins will probably become unbearable during the fermenting and composting processes, so I suspect the bags will have to be ditched given they are in a kitchen area where most cannot bear
 such smells.
Since we did not supplement the grounds for the latest uncooked bags, they have a much better chance of colonizing than the previous bags because the bacterial bloom will be more limited in the lower-nitrogen environment, giving the mycelium some advantage.  And since the supplementation has not been limiting the yield so far because we haven't even gotten a real good four or five flushes after which nitrogen limitation can come into play, I also agree with you in doubting the lack of supplementation will make much difference in yield.
Just to put some perspective in what we are doing here, the normal course of substrate preparation is always either pasteurization or, less often, sterilization immediately prior to spawning in all com mushroom growing operations I have ever heard about or seen.  Although we had some success using Dr. Wayne's novel hydrogen peroxide techniques, as he himself admits, these have not been proven in any commercial operation (and I am betting there are good reasons for that).  If you guys are serious about turning out oyster mushrooms, on coffee grounds or otherwise, substrate heating immediately prior to spawning is probably going to be required because without it the gamble is very high.  Having said that, pressure cooking is not required for substrate pasteurization; there are other less-energy-intensive ways to heat the substrate hot and long enough for pasteurization.

From: Rikke Rasmussen <rikke.c.rasmussen at gmail.com>
To: Roger H <domitron at yahoo.com>
Cc: Dana S. <dsniezko at sonic.net>; "tastebridge at lists.noisebridge.net" <tastebridge at lists.noisebridge.net>; bio at lists.noisebridge.net
Sent: Wednesday, October 19, 2011 10:45 AM
Subject: Re: [Tastebridge] Oyster Mushroom Status?

Ahh, sorry for the lack of update. Here's a quick run-down of Monday's activities and status on the project:

Dan, Matthew, (Lina?), Rameen, Mike and myself all joined in the fun. Dan brought in about 24 lbs of partially dried-out coffee grounds, which we inoculated with the remaining 10 lbs spawn - made 8 bags this time. The grounds were not pressure cooked first, because we didn't have a pressure cooker. We also did not add any gypsum, vermiculite or spawn mate, so it'll be really interesting to see how these come out. I anticipate slow colonization, slightly lower yields, but better resistance to contaminations and infections down the line. 

We would have cooked them if we could, though, as there is a marked difference in colonization rate between the cooked and the uncooked bags - the cooked bags are already 100% on the surface (top, sides and bottom), while the uncooked bags were only just starting to show real sign of colonization on top. That said, it looks the cooked grounds colonize even faster than the sawdust, so I think pressure cooked coffee grounds with or without supplementation will turn out to be our best bet for future runs, especially if we could get two pressure cookers and a double burner for the propane so we could cook 6-8 bags at a time. With cooked bags, we could probably also lower the spawning rate massively - we've been adding spawn to both cooked and uncooked bags about at 62,5% of the dry substrate weight, so that 20 lbs of spawn went into 14 bags of grounds,  which is about 1/3 - 1/4 of what we could be making, I think. 

The sawdust blocks that got soaked overnight last week have started fruiting again like crazy. The fruits this time are generally a little smaller, paler and grow fewer to a cluster, but 4 out of 8 blocks are completely covered, and the rest are pinning beautifully.

Anyone up for a meeting on Monday to have a look at progress, clean out the fruiting chamber, talk automation and make a "mushroom watch schedule"?


On Wed, Oct 19, 2011 at 3:47 PM, Roger H <domitron at yahoo.com> wrote:

How is the second flush of the older bags coming along?  What was the yield like?  How are the coffee grind bags doing?  Did both the pressure-cooked and non-pressure-cooked bags colonize fully without mold?  How many bags did you guys add since Monday?
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