Okay, take your incubator, which should be, if you remember, two Rubbermaid tubs, one used for heated water via the submersible water heater. The other tub is the chamber for your jars and now is going to hold your casings and cakes (but cakes cannot rest directly on the Rubbermaid, they must be put in Tupperware, preferably, your casings would also be in a thick Tupperware, you will see why).

So cut two, three (based on size of your containers) holes in the bottom of your chamber. Try to think of these as vents for steam to enter through. And you want them to be big enough for a lot of steam to enter but also creating the most floor space away from those vents. An easy way to cut the holes would be heating up a knife and cutting into the bottom. Keep the plastic pieces, you may need them later.

Then you fill the water tub with water from these holes all the way up (a bout an inch from the holes). Now would be a good time to conduct the following test. Target (and probably all marts) has this cheap digital thermometer and hygrometer (to measure relative humidity, whatever the correct term is) that should attach nicely into the chamber. Close your tubs up and start trying to get to 80f and 90-99% relative humidity by heating the water more and more. You may have to turn the water heater all the way up to create enough steam to make the humidity, but you also really do not want to get above 85f because that is not a good environment. If you cannot get it to that humidity without sacrificing temperature, do the following. Find something that you can put ice into but will float thin enough in the water in the tub. Basically, what this does is (and you may have to add ice every 16-24 hrs), the ice changes into steam a bit slower than just dropping into the water, which would melt it quicker and not give you the same amount of evaporation and thus, steam. The added steam will allow you to lower your water temperatures lowering your temperature, create more humidity, and will help create a nice heavy oxygen steam for good air in your chamber (but we will talk about that more later). Okay, once you get your optimal condition (80-86f and 90-99% humidity), remember what you needed to set your water temps at, how much ice you were using, and so on.

Now you want to put your case/cakes on the plastic floor as far away from the steam vents. Take some plastic wrap (a piece of Plexiglas will work nicely too) and wrap it in a diagonal line to create a moisture drip slide so that when your steam rises to the top it wont drip onto your casings instead, gravity will have the water slide down and if you are clever about all this, back into your water tank.

There are a bunch of ways to automate this system based on how good you are at building this and the such, I shall explain. The first thing you can do is really simple and just means opening the chamber maybe once a day, fanning it a bit, and if you are using plastic wrap, use a new piece. Maybe you have to add more water to the water tub, but make sure not to use boiled or distilled water. You want to use water that has enough oxygen. Or, again if you are really clever, they have those manual air pumps that you use in an aquarium, they are like five bucks, get one of those and just pump some oxygen into the water in the tub. You can do that really simply; just make a small hole for the tube in between the tubs (so that the hole only pierces the water tub). If you have an air pump and a Plexiglas drip slide, you will never have to open the container, I promise. Maybe you can use an aquarium bubbler thing, but I never tried that. If you never succeed in getting the optimal condition because the humidity made the tub too hot, wire a computer case fan to a 9v and cut a fan hole into your grow tub. Have that running a bit, it will give a good air exchange, lower the temp, and shouldn?t kill the humidity too much. That?s it. Here are some diagrams.

So some things:

As an incubator, you don?t want the steam, so just use cover up the holes with plastic. Some tape will probably work well enough to hold them down. Adjust temperature of the water so temperature in the tub is around 83f.
IME (in my experience) you will achieve optimal grow conditions without using ice, if the water is at around 90-95f and room temperature is at around 60-70. You may have to adjust, but it is not a hassle, a few ice cubes will go along way especially if you do not open that thing and do your best to keep the water oxidated. At the same time though, if you plan on keep it closed, you may want to glue a tyvek filter to the grow chambers wall (cut a hole) because you don?t want the steam to REALLY build in there. The tyvek will keep clean air coming in (especially with the temp grade and pressure difference working to pull air in), it will keep more moisture in, and will even lower the temp a bit. Test the chamber a few days before you begin inoculation, see how it works, room temperature will vary the conditions and maintenance requirements as everything is interrelated (and hence at optimal conditions, very self automated). If you are opening it up anyway to fan it out, add ice cubes, whatever reason, you may want to forget about the drip and just be careful about whipping the top of the container down with something that will prevent water droplets from forming. Change the water every week if you are worried about bacteria (I am a clean freak I guess) and it only takes me a few minutes (I mean I take the tubs out of each other and fill it quicker that way than via the holes). Well good luck and great community you got going here, I?ve always enjoyed what you guys have had to say.