A Kiln, Tobacco, the Process, and Why

[ChinaVoodoo]

According to this research,
http://www.tandfonline.com/doi/full...842884#/doi/full/10.1080/00380768.2013.842884
the initial curing of the leaf involves alpha amylase and proceeds almost exactly like it does in the starch extraction during all grain brewing. The alpha amylase in the leaf breaks down the starches into simpler sugars. At this stage, some of the browning of the leaf can be attributed to the formation of maltose in the leaf. However, in this flue curing process, the maltose is broken down - allowing the leaf to remain yellow.

Somewhere else, i was reading about leaf senescence where protease in breaking down proteins in the leaf also contributes to a brown colour.

I think, DeVries, that kilning longer allows for darker leaf due to further breakdown of the leaf's proteins and maybe starches. I can't comment on temperature, but i believe that the primary factor is the particular starch and protein compliment that the specific leaf starts with, which is dependent on leaf position, fertilizer, sunlight, varietal, etc.these factors dictate the potential the leaf has four darkening in the first place.

I would also suggest that not all starches and proteins will be broken down in the same way.

 

[deluxestogie]

But wouldn't you agree it has to do with the duration of fermentation as well. I think temperature dictates the duration of fermentation. When temperatures are too high the leaf will break/burn next to the stem. When they are too low there is only little of the chemical process going on. But you can certainly "over-ferment" tobacco, thereby giving it a darker colour.

I will confirm that you can artificially darken tobacco by steaming it--a "secret" method used to mass produce oscuro wrapper for cheaper cigars. But if you consider flue-cured tobacco, the very high temps don't actually damage the leaf until you reach about 185-190ºF, although the rapid temp rise (to 165ºF over 5 days) preempts the darkening caused by the oxidase reaction. Very high humidity during color-curing (at ambient shed temps) will yield a darker cured leaf than if the humidity is lower.

I just don't accept the suggestion that maduro leaf is routinely produced with temps above 130ºF. At around 135-140ºF the flavor and aroma take on a somewhat charred character, which you simply don't experience with premium cigars, and at those temps, you lose some of the volatiles that create the nuanced varietal qualities found in excellent cigar leaf.

My experience with my home grown leaf is that problems alongside the stem result from bacterial or fungal damage during color-curing (e.g. barn rot). I've also found that leaf that is poorly positioned within my kiln in such a way that it stays pressed against an interior wall tends to remain cooler than the kiln temp, actively condenses water in the leaf, and comes out blackened and crumbly after a month. I consider both of these outcomes to be errors, rather than methods.

Bob

EDIT: ChinaVoodoo, the referenced article is about the process of color-curing, rather than the so-called fermentation or kilning.

Bob

 

[ChinaVoodoo]

Yes, the article is definitely about curing as opposed to kilning. I also can't find the reference where it spoke of protein degradation causing darkening of leaf, so really, my post is anecdotal. I did stress that the intrinsic carbohydrate and protein makeup of the leaf is the true source of colour potential, rather than the method of kilning,which simply develops that potential. The enzymes bring it out, but only if it's there in the first place. Eg. You would be hard pressed to make maduro out of a lemon Virginia mud lug.

 

[Tutu]

I will confirm that you can artificially darken tobacco by steaming it--a "secret" method used to mass produce oscuro wrapper for cheaper cigars. But if you consider flue-cured tobacco, the very high temps don't actually damage the leaf until you reach about 185-190ºF, although the rapid temp rise (to 165ºF over 5 days) preempts the darkening caused by the oxidase reaction. Very high humidity during color-curing (at ambient shed temps) will yield a darker cured leaf than if the humidity is lower.

I just don't accept the suggestion that maduro leaf is routinely produced with temps above 130ºF. At around 135-140ºF the flavor and aroma take on a somewhat charred character, which you simply don't experience with premium cigars, and at those temps, you lose some of the volatiles that create the nuanced varietal qualities found in excellent cigar leaf.

My experience with my home grown leaf is that problems alongside the stem result from bacterial or fungal damage during color-curing (e.g. barn rot). I've also found that leaf that is poorly positioned within my kiln in such a way that it stays pressed against an interior wall tends to remain cooler than the kiln temp, actively condenses water in the leaf, and comes out blackened and crumbly after a month. I consider both of these outcomes to be errors, rather than methods.

Definitely. I was simply saying that over-fermentation makes leaf darker, but had all ranges of tobacco in mind. Over-fermentation is a method used, for example, to darken fillers. I was definitely not talking about wrapper material. My point was that if the temperature during fermentation goes up to rapidly you will damage the leaf right next to the main vein, if we're talking thin wrappers. I'm talking about a 5 ton fermentation pile with leaves in the middle getting damaged because they aren't moved to a cooler position in time. Thus a higher temperature (in a short time span) and additional fermentation would not produce higher quality darkened wrapper.

 

[Floppy2]

New tobacco grower. My guys need some leaf to smoke and do not want the commercial stuff. Since I was growing food, why not smoke at the same time. I will ask my husband to build this kiln for me (and for him if he wants cigar leaf).

bjr

 

[deluxestogie]

Check out the simple kilns linked in the Index to Key Forum Threads: http://fairtradetobacco.com/threads/3868-Key-threads-in-the-FTT-forum, under "Curing." I am partial to my endoskeletal kiln and Knucklehead's exoskeletal kiln.

Bob

 

[SmokesAhoy]

I also got tired of the drip from the wet kiln. I read over every single post in this thread again to hopefully distill everyone's experiences into something that will work for me. I have a hot plate at the base on fire bricks with a firebrick on the burner to help give it a more even heat dispersal. On the shelving is one layer of pink insulation cut to fit but that was too poofy so I cut a layer of the rigid r10 I think it's called foam to serve as a shelf and placed that on the pink insulation. I did this after reading Brent's thoughts on layering cardboard to combat the movement of moisture away from the bottom most leaf over time.

Leaf is in heavy zip lock bags compressed and excess air forced out before sealing.

Another reply said that moist totes stopped the migration of moisture from inside the bag to outside of it, so I put the zip locks inside big trash bags with a good amount of water.

I've been dealing with the drips too long, hopefully these changes address that. Great thread. One thing I noticed same day was less cycles of the power going on and the stream leading to the drain is starting to disappear.

I was a little concerned about plastic bags with a burner in the same box but it seems unfounded, maybe due to the excessive amount of insulation in between the glass shelf they're resting on and the firebrick on top of the burner. Anyway it's going good, and the dry basement is awesome.

 

[SmokesAhoy]

And a question, because everything is in wet bags, my thought process was the optimal point for the temp probe was in between the bag and the insulation. Bags just laying on it. Does this sound about right to anyone else?


Edit, needs to be further out, was too insulated there, was hitting 135 at the edge of the pile.

 

[Jitterbugdude]

Just moisten the leaf and fill up your container/bag. I also vent once per day. Sounds like you are way too wet (by adding water to your bags).

 

[ChinaVoodoo]

It seems to me three quarters of kiln problems stem from designs that don't incorporate humidity controllers. My kiln: those mesh inserts that go in seedling trays--> I stack leaf in those, not in bags, and put different tobaccos in each tray, about 6 trays high. The bottom tray is empty and upside down so air can flow under the stack. Nothing touches the floors or walls. There's a humidifier. There's a short section of duct with inline fan, and lightbulbs inside for heat. The fan sucks vapor from the humidifier and heat from the bulbs through the duct and blows it all over the place with gale force. Voila, every square inch of the kiln is the same temperature and humidity. No ambiguity.

 

[SmokesAhoy]

My leaf is medium to high case very spongy but rubbing it elicits some noise, the water is actually in a bag that the zip locks are in only about an ounce. The idea was further back in this massive thread, get your leaf to perfect case in it's own bag. Then place that in a high humidity container so there is no chance of drying out inside it's individual bags. I'm not sure if it's helping but it is definitely not hurting. The leaf in the individual zip locks is perfect from edge to edge within the zip lock. Even with the wet heat source I was getting spots where there was dryer edges. I guess another test is in order to see if the secondary high humidity bag is needed, but I've finally got everything perfectly dialed in with this current set of variables so I don't want to change anything this run.

It's set to 123, with a turn on of -5, so 118 on and it's peaking at 127 before starting to drop. I'm sold on the dry method, but I do want to explore the necessity of using the secondary bag. But I'm pretty sure it could only help stop/slow the moisture exchange.

 

[BarG]

Thought I'd shear to help out my fellow smokers (there are many methods - this one works for me).

Why Kiln Tobacco? - Simply put, ya get a nice smoke....

Fermentation & Aging of Tobacco

Big Tobacco had a fine product until it was decided to increase addiction power among other things and the government feeling the need to turn smokers into cash cows. Why try to duplicate that brand cigarette a very hard thing to do considering. As for me my interest is simply a good to great smoke.

I had a realization while looking for information in regard to process & method for the function, need, and benefits of Forced Aging Tobacco ( Kilning). The general accepted means for those of us at home is to use a crock pot and a discarded refrigerator. I think the idea is a by-product of methods used to ferment Cigar Tobaccos.

Do you need to age / ferment tobacco to smoke it - No you do not - but better tobacco is.

Big tobacco has employed Tersa Bales in polyethylene and or cardboard packaging, storing the tobacco in climate controlled facilities. This brings wonder to my mind why, WHY the polyethylene? I've concluded it is to combat the loss of moisture within the tobacco in a heated or cold storage environment to promote or extend aging. (Seems to Justify my plastic tub.)
Some of the PDF documents I have found may lend support to this conclusion although it is not stated in them.

As far as a Kiln goes I have tried most everything that can be found on line in the way of method. I know Mr. Jitterbug uses a process very much the same as what I am doing. We just had the same idea but did not copy each other.
I think a person would be hard pressed to find a way that is easier while keeping control of what is going on. I wanted to force age my tobacco and get the best finish I could, but holding humidity in the air was a problem and keeping a tight percentage of humidity was a bigger problem. Then came trying to keep the moister of the tobacco uniform across the leaves - next to impossible. Unless your hanging them and you would still have some trouble.


What is needed to have a Kiln that works.

As far as the Kiln goes any box with lid or door that is well insulated and won't pollute the air inside with unwanted or even toxic gases will work just fine.

Heat source can be anything that is safe, does not get extremely hot but will get up to about 200F, and can be controlled. I use a small griddle (it has legs). It is set on a piece of cement board so I don't need to worry about the floor getting to hot. The griddle has built in heat control but it can be not so good for controlling heat in the kiln, so I just run it set on high. My griddle is plugged into an outlet I mounted on the inside wall of the kiln and controlled by the power to the outlet being turned on and off.

Heat control can be any thing that will operate as a thermostat that has the ability to switch power on and off and has a plus minus of not more than say 4F of a set temperature. You want good control but it need not be supper great.
I also use a few fans to circulate the air this helps keep the interior temperature uniform so I don't have any real hot spots.
(I use a PID = well really I use two, one el-chepo just to see what my temperature is at the ceiling and the other a better one to control power to my griddle)

To solve the moisture problem I use a plastic tub like the one below in the photo. To fill it I layer the tobacco and mist it with spring water between the layers.

If you are thinking of Kiln for your leaf tobacco, think of what the greatest amount of tobacco might be that you will ever kiln and make or get a kiln big enough for that amount.
.
View attachment 10317



.
I have found these tubs at Walley Mart and Lowe's they do come in different sizes, note the lid has a gasket. If and when you use plastic be sure it will not leach chemicals to the tobacco.

If you do this be sure not to get your tobacco to wet or it will surely mold, if to dry it will not ferment as wanted.


A few links that can help in understanding - those with stars at the start I think to be better. But they are all interesting and may be helpful, if you like one you may want to download and save it starting a collection of reference material.

***** A 45 page document Natural and Forced Aging of tobacco - starting on page 12 forced sweat / aging note the temperature range from about 90F to 120F & R.H. of 75% - Darkis & Hackney (I like 117F to 121F for bright leaf). Also not page 16 near the bottom " higher temperature seemed to have reveres effect.
(I love this document because more than one forced method is discussed with the differences between them. Also note the addition of Yeast to the process. - page 32
http://legacy.library.ucsf.edu/tid/ubb93f00/pdf?search="aging tobacco process"

Summery of change - VA Bright Flue Cured
http://legacy.library.ucsf.edu/tid/jnc20j00/pdf

Data over 3 year period a Kiln can possibly get this done in one to two months
http://legacy.library.ucsf.edu/tid/vuu54f00/pdf

An interesting comparison Forced Aging ver Natural Aging of Flue Cured Tobacco
http://legacy.library.ucsf.edu/tid/uvu54f00/pdf

This PDF had me scratching my head - my little kiln says different
http://legacy.library.ucsf.edu/tid/mhd12i00/pdf

I found this letter of 1963 to be interesting, especially the reference to the 1930 process
http://legacy.library.ucsf.edu/tid/mvh65a99/pdf
Interesting notes on Oils & Taste
http://legacy.library.ucsf.edu/tid/pak40d00/pdf

Information - container type after or during Forced Aging
http://legacy.library.ucsf.edu/tid/iwa63d00/pdf

Forced aging Temperature & R.H. levels - test using polyethylene and cardboard
(my tobacco would certainly mold if I were to use cardboard) the writer points out the process is supposed to be the equivalent of two years natural aging.
http://legacy.library.ucsf.edu/tid/tbz76a00/pdf

This PDF deals really with the promotion of a belt manufacture's belts, but does give some insight to processes carried out in a modern tobacco plant.
http://www.createbelt.com/uploads/soft/120621/1-1206211A126.pdf

Flue cured tobacco sugar loss and aging
http://legacy.library.ucsf.edu/tid/ayv80a00/pdf?search="aging tobacco process"

This document touches on changes incurred when tobacco is aged
http://legacy.library.ucsf.edu/tid/med90a00/pdf?search="aging tobacco process"

An interesting document "The Maverick Formula"
http://legacy.library.ucsf.edu/tid/med90a00/pdf?search="aging tobacco process"

***I am trying to relate the information found in this B&W Tobacco Aging document to change I have noticed when aging in my kiln - The 4 weeks = 2 Years theory
http://legacy.library.ucsf.edu/tid/wkv31f00/pdf?search="aging tobacco process"

*** This document was interesting because B&W states the optimum temperature to be 120F with 85% R.H.
http://legacy.library.ucsf.edu/tid/lea00f00/pdf?search="aging tobacco process"

*** A simple break down of what happens during fermentation - I too see the release of Carbon Dioxide & Ammonia through 4 plus weeks in my Kiln.
http://legacy.library.ucsf.edu/tid/omm31f00/pdf?search="aging tobacco process"

There are many more such documents but finding really good information can prove difficult.

Allowing the tobacco to Cold Sweat or Rest after you have removed it from the kiln will / can extend improved qualities.

I am stead fast sold on the use of a kiln for leaf tobacco, it need not be complicated or fancy it has but one job to do, hold heat at a given temperature over a period of time.

If you follow my lead there is no need for venting or the introduction of humidity to the air within the kiln. Also if using sealed container/s you can age more than one kind of tobacco at a time without mingling taste and aroma. Plus the ability to age a batch with different levels of moisture in different containers.

Remember it takes weeks to complete the process so I would recommend buying 5 to 10 pounds of tobacco at a time or growing a crop. With object of aging more than what is needed creating a reserve for the future.

Most studies for artificial aging in the above documents were carried out over a time period of 3 to 5 weeks.

For more documents visit this link - note document type an number of pages (helps the search) also you can play with search terms in the search box.
http://legacy.library.ucsf.edu/acti...th=true&drf=ndd&asf=ddi&p=3&ef=false&hd=false

I wasn't gone that long, how did I miss this I wonder.

 

[deluxestogie]

Note that a kiln at 120ºF and below must regulate its humidity to be 75% or less, since temps below 120ºF will not inhibit vegetative growth of mold. A kiln running at 120-125ºF does inhibit mold growth, so the humidity can be allowed to go as high as it goes, without any regulation.

Bob

 

[Paraord]

howd you make out? Work has been brutal, so I havent gotten back to this yet but I will at some point! On a side note for your entertainment idiot newbie thought salt was mold, had a pile of mix matched tobacco.....it was salt.....I have a pile of random unknown tobacco back in the kiln. Happy friday all!

 

[ChinaVoodoo]

I have a pile of random unknown tobacco back in the kiln. Happy friday all!

Don't we all?

 

[Orson Carte]

Going back to the root of this thread; what the hell ever happened to AMaxB? A great contributor who just 'disappeared'. Online 'deaths' are a fact of life but, nevertheless, uncomfortable to accommodate.
What a great inspirational and altruistic/educational guy he was.
Every time I see this great thread regenerated I'm drawn to wonder if he is still extant. I suspect not, but would relish it if I was wrong.

 

[Jitterbugdude]

I believe he retired and moved to Vermont.

 

[Gmac]

I thought it was Maine. I remember reading in his posts, He talked about offshore fishing and hunting.

 

[Muggs]

I am new to this baccer growing and processing,but the one Ingredient that works best, IS TIME.
Anything worth while takes time.

 

[LeftyRighty]

About humidity in the kiln -
I never liked too-wet leaf in the kiln, and solved the problem by leaving the lid on the crock pot. There is generally enough moisture still escaping the crock pot lid that the leaf stays in proper case. If I find the tips or edges of the leaf getting dry, I just off-set the lid slightly. Proper design of a kiln should include some form of ventilation to the outside to prevent excessive moisture build-up - just a small hole (1/2-inch) near the top & bottom of the kiln is adequate, and it can be partially blocked if loss of heat/moisture is excessive.
I find it pointless to worry about adding humidifiers and controls for such - too easy to solve with a good crock pot design, and attention to the leaf.
I probably over-pack my hanging leaf in the kiln, to get as much as possible per each kiln cycle, then tie a string around the leaf to bundle it together, and away from the kiln walls - yeah, the walls get wet and messes with the leaf.

Just keeping it simple