Back when I was trying to ferment my previous crop of tobacco, I used a solar-powered fermentation chamber. It was a garden trashcan with a glass lid. The bottom had a few inches of water and the tobacco leaves were suspended above it. The idea was that the sun would heat up the chamber like a greenhouse and the water would evaporate giving the leaves a hot, humid place to ferment. The hygrometer I had inside the chamber told me that it never got very humid, so I kept spraying the leaves with water. In time, they molded.
None of that was necessary. Dig the data from my latest experiment.
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| Click on the image for a readable version. |
I put one of my new hygrometer sensors in a sealed Tupperware with an inch or so of water in the bottom. The sensor is attached to the lid so it's just a few inches from the water. It's reading 100% humidity. A reservoir of water is sufficient to humidify a sealed chamber. The second sensor in that graph is outside the Tupperware container, sitting on the lid.
I'm not available to try this next experiment right now, but in a few days, I'm going to reconstruct my trashcan fermenter and put two sensors in it, one a third of the way up the side, the other two thirds of the way up the side. My bet is that close to the water, the humidity is high and close to the top, the humidity is low.
All I had to do back then was to put in a small fan to circulate the air so the whole chamber got humid. I ruined my tobacco crop by spraying water on it because I didn't realize that without air circulation the humidity level was a function of distance from the water.
Argh.
Yes, it is pretty likely that you had stratification of the air, with the most humid air down near the water and much drier air higher up. If there isn't any convection, then diffusion is much, much slower. All of our drying ovens in the lab use forced convection for this very reason.
ReplyDeleteIt is also possible that your old hygrometer simply didn't register correctly. Most of the hygrometers I have used over the years turned out to be very imprecise.
What occurred to me is that all I needed to do was think about the atmosphere. It stands to reason that directly above a lake, the air would be more humid than the air, say, 10,000 feet up, depending on the clouds, of course.
ReplyDeleteI'm really looking forward to the next experiment.
You know, it might be nice to experiment with something broadly similar to tobacco, while you wait for your tobacco plants to grow. That way, you can try things without having to wait, or taking a chance on destroying the thing you care about. Some plant with leaves of similar size and texture would probably do. Around here, I'd probably use burdock or rhubarb leaves. Ornamentals like hostas would be good too, if you or your neighbors happen to have some. If all else fails, maybe just buy a head of romaine lettuce or bok choy.
ReplyDeleteBrilliant! In keeping with the theme, I think I'll try collard greens. The leaves are dense, much like the tobacco.
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