Kiln temp issue

[Dean]

I'm sitting at 127.5 I am wondering how accurate these hot water thermostats are as it's set at 120. The thermostat is just hanging mid chamber using air temp to set it on and off, I am over the desired temp but it has not switched off yet in 12 hours I just popped the nob and wound it back a few degrees to see if this gets me closer to 120. Is this common.

i have 3 diferent types of thermometers in there all reading the same.

cheers

 

[Dean]

Am I right in thinking the thermostat needs to be positioned on the outside to make a temp differentiation?

 

[DGBAMA]

The setting on the water heater thermostat is not going to be exact. I mounted a "heat sink" to mine where it would normally be in contact with the water tank which helped. The little plastic pointer can also be repositioned carefully on the adjusting screw once you figure how far off it is, or just make a note of the discrepancy and take it into account when making adjustments.

 

[Jitterbugdude]

The setting on the water heater thermostat is not going to be exact.

Mine used to fluctuate about 10 degrees either way. The temp swing isn't really that critical as long as you stay within the 110 to 130 range.

 

[Dean]

So it should be fine on the inside just hanging? I have already adjusted it to run a bit lower.

humidity is good but the temp is driving me ,ad I'll just persevere with it then till it runs right.

 

[DrBob]

the thermostat should be in the chamber. it does NOT need a heat sink. It is normal for these thermostats to have a spread of 10 degrees f. This is just fine and will cause no problems. I actually think it is better for the temps to fluctuate 10 degrees anyway. I have used water heater thermostats exclusively for years. as long as the temps do not go under 115 or over 135 you will be ok. This aint rocket science it is just a way of speeding up the natural aging of tobacco.
Dr.Bob

 

[deluxestogie]

I agree with all the comments above.

A heat sink will shorten the latency between a change in the chamber temp and the subsequent change in the temp of the thermostat, so it will "know" a little faster. If you plan some finely granular experiments (complete with frequent data recording), then it might be worth fussing with it. Otherwise, it doesn't matter.

Why doesn't it matter?
In a commercial setting (or a laboratory), the leaf used (in whatever processing) is highly homogeneous--it has been sorted into complete batches of nearly identical leaf. So tiny adjustments in the curing environment may be detectable in the leaf product. For a home grower, even with sorting of leaf into 4 or more stalk positions, any single batch of leaf will span so many different grades that fiddle-diddling with small variations in the temp and humidity are difficult to see in the final leaf. Even year to year variations in the leaf respond differently to the same kilning conditions.

So, if I were planning to publish a paper on my kilning results vs. temp and humidity differences, I might even go to self-documenting digital controls. But still, I don't have fine enough control over the leaf itself to expect useful data.

Bob

 

[DrBob]

you are wrong bob think about it.

 

[AmaxB]

I feel tools and method are key, than comes the question how much / often will you run your kiln. Can higher cost of tools be justified?
No matter you can still get a nice finished smoke with this or that, but the better your understanding, method, and tools the more consistent the outcome.
I'm finding a closed tobacco environment, damp tobacco, temp of 120 to 125 create a nice smoking tobacco most of the time.
It's a hot water thermostat flux can be expected..

 

[Fisherman]

My thoughts are to leave it alone as lower 120's are condusive to mold growth and higher than 125 or so is best for stopping mold growth.

 

[Brown Thumb]

My thoughts are to leave it alone as lower 120's are condusive to mold growth and higher than 125 or so is best for stopping mold growth.[/QUOTE
I am running 125 also 90 % rh First batch comes out of the kiln sat.
smells good looks good, I would not worry about your temp you have.

 

[deluxestogie]

you are wrong bob...

That's not unprecedented. Which part of what I wrote appears to be wrong?

Bob

 

[Boboro]

You ant gonna get much better with a water heater thermostat. Good to go!

 

[Dean]

All good then, I just thaught I'd have more control.

thanks guys.

 

[AmaxB]

I must disagree - Mold can be avoided while working at lower temperatures.
My method the last few months and I have had zero mold issue..
In the graphic I provide a simple look at my set-up. Note there is no source for humidity and no humidity control.
Air is driven clock wise in the Kiln creating uniform temperature within, the containers are sealed. When I fill the containers
I mist the tobacco and the moisture leaches through all the leaves. The tobacco becomes uniform in moisture content
and the moisture cannot escape (a Minny Environment) every few days lids are removed for a minute or so to allow
used air to be replaced with fresh air (getting rid of the garbage). If the tobacco reaches a state of feeling a little dry
I remove that container, remove the tobacco and repack the container while misting, than put it back in the Kiln.
After 2 weeks sampling begins every few days when it reaches a point I like the tobacco is done and removed from the Kiln.
When checking the tobacco it should feel soft and moist but not wet. When my tobacco has finished if it feels a little to damp
to bag and put up I will crack the container lid for a few hours and then remove when it feels right.

I usually run at about 121F or 123F I have run at 118F without mold. In my research I have read that in some houses and dependent
on variety piles are broke down and rebuilt when temperature reaches 116F to 128F.

I feel this is a very easy way to age, there is no water or ambient humidity to control.

Give this a shot Bob it can make some very nice wrapper, elastic, and soft - thin leaves are awesome.
.

 

[AmaxB]

I can't say how this works with small containers (under 5 pounds)..... I would think it would be ok as long as they are sealed.

 

[Fisherman]

the key would be to have low enuff humidity in your mini environment thus prevewnting the mold in the first place. Your method is good tho for controlling humididty as it should remain constant in the closed container. But closed or not I would think that excessive humidity would almost always cause mold?

 

[DrBob]

That's not unprecedented. Which part of what I wrote appears to be wrong?

Bob

The temperature sensor should not have a heat sink, The mass of the heat sink will delay the on and off times of the thermostat causing greater temperature fluxuations in the chamber.

 

[Rickey60]

I can't say how this works with small containers (under 5 pounds)..... I would think it would be ok as long as they are sealed.

I agree with AmaxB. I have been using his container method now for about 6 weeks with great results. No mold. Before I used his method I was always fighting mold in the high humidity chamber. Now I just check my containers every few days and mist if needed. I run at 121 degrees and have good air circulation. All my containers are under 5 lbs.

 

[deluxestogie]

The temperature sensor should not have a heat sink, The mass of the heat sink will delay the on and off times of the thermostat causing greater temperature fluxuations in the chamber.

Dr. Bob,
I see what you're saying. That's an interesting issue.

The sensor of a water heater thermostat is engineered to be directly attached to the exterior of a metal tank of heated water, so that the entire surface area of the tank serves as its liquid-heated heat sink. In a kiln, the tiny sensor is exposed only to a small surface of much lower density air.

If the thermal conductivity of the heat sink and that of the exposed sensor were the same, I believe that you would be correct: increased mass would slow the temp registration during changes in ambient temp. On the other hand, if the heat sink were made of material with significantly greater thermal conductivity than that of the sensor, then I would imagine that the exposed surface area of the heat sink would come into play. My brain is too crusty to do the math. Air flow (by fan or even by convection) past the heat sink would determine the time required to bring the heat sink into equilibrium with the ambient temp. With that thermal flow, I would expect the mass of air in contact with the high surface area of the heat sink to transfer more energy to the much smaller heat sensor than the relatively tiny mass of air that would otherwise be in contact with the sensor alone.

You may indeed be correct, but that's my notion of it. I suppose it would be easy enough to test, if a kiln contained two heat sensors--one with a heat sink and one without. But I'm too lazy to fuss with it.

Bob

EDIT: In my wooden, baby kiln, a hole in the wood allows the sensor of the thermostat to be exposed to the air inside the kiln, with no heat sink. In my Cozy Can, a similar thermostat is attached directly to the exterior of the metal can, which serves as a heat sink. The tobacco that comes out of the two can not be distinguished.