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ExtravagantDream
Beacon in theDarkness


Registered: 10/24/02
Posts: 1,271
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Temperature Variation Theory
#1688484 - 07/05/03 05:35 PM (21 years, 8 months ago) |
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Temperature Variation Theory
I would first like to say this is entirely inconclusive. I have not heard of anyone performing any type of tests on this nor has any valid data been collected. So in essence this would be more of a hypothesis with some background knowledge.
TVT- A few years back, when I first became aware of mycology, a more experienced cultivator advised me to change temperatures during incubation. At the time s/he did not explain how this made any difference and only told me s/he had increased the rate of colonization by mimicking the environment.
I followed the advice for some time but have never kept too close of watch to really notice any difference. The distinction of a few days means little to me and could be caused by many variations. However, since I felt it might contribute towards the advancement/fine tuning of cultivation in the community, I have decided to share this with ?you.?
The reason I believe this truly to work is not because of mycelium enjoying temperature variations or the mimicking of the environment but because of physics. The simple law described as PV=nrT will validate my conjectures.
All matter has a specific heat, energy required to change the temperature of that matter by 1 degree Celsius. All matter also tries to maintain equilibrium with its surroundings, such as uniform temperature and pressure. When substrate is colonizing inside of a jar with a defined volume, temperature changes will induce positive and negative pressures due to the immediate change in temperature outside of the jar, and the much slower change inside.
Cooler air is denser due to the lower energy and ability of atoms to collide with each other at high velocities and fly far apart and also has lower pressure in a given volume. Starting in a warmer ambiance, when the air temperature is dropped outside of the container the warmer air inside with a higher pressure will escape the container until equilibrium has been formed in pressure. Once the substrate has cooled as well, dropping the air temperature inside, air will be sucked back in to make up for the lower pressure now inside of the jar. The opposite will occur during heating.
So what the heck does all this do? Well, just like humans, mycelium produces CO2 and needs O2, in a different manner of course. Temperature changes provide an effective air exchange without replacing too much CO2 and initiating pinning.
In consideration, this method will only work with fixed containers such as jars and not with bags. If interested a simple experiment to prove this can be done. Take several samples of both bags and jars with equal substrate kind and amount, equal strain, light and well, everything. There should be four different samples, bags with temperature changes and bags without, and jars with and without changes.
Results should show that in the jars with changes, colonization is faster than jars without. The bags should colonize relatively equal, the one without probably slightly slower due to not always being at ideal temperature.
This topic is open for discussion and I welcome criticism as long as it is kept subject related.
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lemunhed
The hustler'shustler

Registered: 05/12/03
Posts: 775
Loc: Ur moms house
Last seen: 19 years, 8 months
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I am an amateur mycologist at best, and not a master physiscist, and thus i have to way to accurately measure air expansion. I would guess that the air exchange due to pressure generated by 3-4f in temperature variation is negligible. I think if you used enough variation to facilitate good air exchange, you would offset those benefits by being too far outside the optimal 86f temperature. On the other hand, air exchange is important and one should seek to create this in their jars when incubating. Use of polyfill lid filters and tyvek filter disks is *probably* superior to temperature fluctuation. Thats an interesting theory though, and i bet to some extent it does work. You get 5 mushrooms for that.
-------------------- You're pompeius, aren't you? I'll make a pompeian of you unless you hold your toungue!
-Tiberius Claudius Nero
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ExtravagantDream
Beacon in theDarkness


Registered: 10/24/02
Posts: 1,271
Loc: Somewhere in the Local Su...
Last seen: 17 years, 10 months
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Re: Temperature Variation Theory [Re: lemunhed]
#1688515 - 07/05/03 05:58 PM (21 years, 8 months ago) |
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I agree it would do little but I think it is enough. I was considering more on the lines of 10-14 degrees F variation, from the optimal temperature down to room temperature. This done once a day should be sufficient for an air exchange. Filters for jars are a must, after all, we wouldn't want contaminants. However, air will not move itself, so a force must be applied.
I understand air exchange can easily be accomplished by turning jars upside down but who wants to do that when they could just have an incubator on a timer. It is not extra work and also helps to save some energy. Negligible, probably but I would hope there are a few on the board to optimize their growing experience.
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ExtravagantDream
Beacon in theDarkness


Registered: 10/24/02
Posts: 1,271
Loc: Somewhere in the Local Su...
Last seen: 17 years, 10 months
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Ok, I'm sad to see only one person reply and since it took me a while to type, I will not settle for only forty people looking at this. I guess most people's attitude is towards the saying, "If it ain't broke why fix it."
In any case, I've been giving this more thought and realized that my statements were partially incorrect. Atm will hardly change under a few degrees temperature difference. However, when looking at the container itself and looking at the volume of gas inside at a certain temperature, it should be noted that for every degree C the temperature of the gas is cooled the volume is decreased by 100/27315.
My previous statement suggested that when the room temperature is changed it would induce an immediate pressure change to cause gas effusion; this is still true but to a very minimal amount, much less than I had expected. The real air exchange occurs during the second part when the substrate temperature changes allowing the gas inside the container to change as well. Unfortunately, this is a dreadfully slow process causing little turbulence, most likely leaving CO2 sit still at the bottom of the container
The more drastic the fluctuation of gas inside the container the more CO2 will escape. This causes for a problem since glass tends not to conduct heat well and water content in the substrate has a high specific heat. Perhaps leaving the jars upside down where CO2 will not only leak out naturally but also be the first to effuse out during temperature changes. This would also help due to the metal lid conducting heat much better, allowing mostly CO2 in contact to cool much more rapidly.
Unfortunately, I fear this will cause too much air exchange.
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