Small scale tobacco "sweating"

[PressuredLeaf]

With my first season of tobacco growing winding down, I'm now getting more involved with the curing process. For my tobaccos I built a small kiln to help with the curing process. This worked beautifully for the sun cured and flu cured tobaccos, but with the very first priming's of cigar tobacco it didn't quite go where I wanted. I noticed all of the kilned tobacco took on a delightful toasty sweet smell, kind of like sweet rolls or something similar. This is great for the pipe varieties, but it's not what I was looking for with the cigar leaf. Something I have read/seen in videos over and over is the pilone fermentation of cigar leaf to release ammonia as a major part of the post harvest processing. I have never noticed ammonia in my kiln. I didn't think much of it because pilones are made from 1000's of pounds of tobacco, and I'm working on a much smaller scale. By chance I noticed something very interesting. I had a pile of 50 or so leaves of yellow twist bud wrapped up in a towel to yellow before hanging (since I'm in a very arid climate), and I had to go out of town for a week. I was very worried the leaves would rot while I was gone, and tossed it up as loss. However, when I came back I noticed something very interesting. The leaves in the center of the pile were very dark with hardly any mold, and there was a strong ammonia odor. I ended up putting these leaves in a trash bag to continue the process, while occasionally airing them out. This ended up being some very tasty tobacco, and it got me thinking if I could replicate the process with cigar leaf.

I had two hands of tobacco yellowing, one of corojo and the other of piloto. Once the leaves were yellow, I hung them up in a closet to dry. After a few days, the leaves were curling, but the midrib was still wet. I then took the leaves and put them in a trash bag to maintain humidity. After about 2 days the smell of ammonia was very apparent, and the bag was moved to the garage which is at about 100f. The ammonia smell is still very strong, even after a few weeks. Surprisingly, there is very little mold - i think the ammonia may be an inhibitor. With these first leaves serving as a proof of concept, I put some more corojo in a separate bag and will be attempting to replicate the process. However, this second bag will be at a lower humidity - closer to medium case. I've already sampled some of the first fermenting leaves, and after drying out they smell "cigar" like- that kind of musty earthy smell. When burned in a small puro, they even tasted like cigars with a harsh edge! My plan is to "sweat" the leaves until the ammonia production goes down, then dry them out and age for a while. I'll update this thread as things progress.



1st bag is new corojo, 2nd is already fermenting corojo and piloto. With the fermenting leaves, you can no longer feel the oil on the leaf ( they are not longer sticky/tacky when you squeeze them).

 

[Oldfella]

Interesting. I'm looking at the same idea as I like the cigar taste and smell of it burning, as I have no teeth I find that I am unable to smoke cigars or a pipe.
I'm thinking of using it as a blend in my cigarette tobacco. I'll be watching your progress with interest. Good luck with your project.
Oldfella

 

[deluxestogie]

So far as I can determine from the physics and biochemistry of pilon fermentation, there are two factors at work. This assumes the leaf has already color-cured to brown, and is not appropriate for green or yellow leaf.

First, the weight of the pilon may apply tons of weight to the floor supporting the entire pilon, but the pressure per square inch on the tobacco at the bottom of the pilon is negligible (certainly in the low single digits psi). [Picture a pile of tobacco that is 1"x1" and 5' tall.] Further, it is in the center of the pilon, not at the bottom, where the temperature rises most. Instead, the dimensions of the pilon seem to be acting mostly as thermal insulation. That is why it needs to be repeatedly torn down and rebuilt, so that eventually all the leaf has rotated to the center, where the temperature rises the most.

Secondly, the source of the temperature rise is the exothermic reaction of intrinsic leaf enzymes that are oxidizing carbohydrates and (the source of the ammonia) albuminous proteins. As the amino groups are cleaved from the proteins, ammonia molecules are created. Microbial studies of this fermentation process shows all sorts of microbes, BUT...the microbes are least numerous when the fermentation is most active. So the bugs are there incidentally, and are suppressed by the heat of the enzymatic oxidative process, and likely play little role in this part of the story.

Key to active oxidation is sufficient moisture (low case seems to be sufficient). Since the rate of enzymatic reactions increases exponentially with the ambient temperature (up to the temp at which the enzyme itself is destroyed), the thermal insulation of the center of a pilon is where most of the action happens. A long-stem thermometer--like a compost thermometer--is passed through a metal tube to the very center of a pilon, to monitor the temp. Once it reaches about 128°F at the center of the pilon, the pilon is broken down and rebuilt. The process is repeated until the temperature rise becomes negligible.

So you need heat (to save years of patient waiting) and moisture. That is the entire purpose of a tobacco kiln. The insulated kiln provides the heat evenly to all the tobacco inside it--regardless of how much or how little tobacco is in there, and the moisture keeps the oxidation going. Unlike flue-curing, you start with fully color-cured (brown) leaf, try to stay above 122°F to prevent mold growth, and stay below about 130°F, to avoid nuking the enzymes or toasting the leaf.

Bob

 

[PressuredLeaf]

Interesting. I'm looking at the same idea as I like the cigar taste and smell of it burning, as I have no teeth I find that I am unable to smoke cigars or a pipe.
I'm thinking of using it as a blend in my cigarette tobacco. I'll be watching your progress with interest. Good luck with your project.
Oldfella

Thanks Oldfella, so far the results are encouraging. I'll do my best to keep this updates as things go along.

So far as I can determine from the physics and biochemistry of pilon fermentation, there are two factors at work. This assumes the leaf has already color-cured to brown, and is not appropriate for green or yellow leaf.

First, the weight of the pilon may apply tons of weight to the floor supporting the entire pilon, but the pressure per square inch on the tobacco at the bottom of the pilon is negligible (certainly in the low single digits psi). [Picture a pile of tobacco that is 1"x1" and 5' tall.] Further, it is in the center of the pilon, not at the bottom, where the temperature rises most. Instead, the dimensions of the pilon seem to be acting mostly as thermal insulation. That is why it needs to be repeatedly torn down and rebuilt, so that eventually all the leaf has rotated to the center, where the temperature rises the most.

Secondly, the source of the temperature rise is the exothermic reaction of intrinsic leaf enzymes that are oxidizing carbohydrates and (the source of the ammonia) albuminous proteins. As the amino groups are cleaved from the proteins, ammonia molecules are created. Microbial studies of this fermentation process shows all sorts of microbes, BUT...the microbes are least numerous when the fermentation is most active. So the bugs are there incidentally, and are suppressed by the heat of the enzymatic oxidative process, and likely play little role in this part of the story.

Key to active oxidation is sufficient moisture (low case seems to be sufficient). Since the rate of enzymatic reactions increases exponentially with the ambient temperature (up to the temp at which the enzyme itself is destroyed), the thermal insulation of the center of a pilon is where most of the action happens. A long-stem thermometer--like a compost thermometer--is passed through a metal tube to the very center of a pilon, to monitor the temp. Once it reaches about 128°F at the center of the pilon, the pilon is broken down and rebuilt. The process is repeated until the temperature rise becomes negligible.

So you need heat (to save years of patient waiting) and moisture. That is the entire purpose of a tobacco kiln. The insulated kiln provides the heat evenly to all the tobacco inside it--regardless of how much or how little tobacco is in there, and the moisture keeps the oxidation going. Unlike flue-curing, you start with fully color-cured (brown) leaf, try to stay above 122°F to prevent mold growth, and stay below about 130°F, to avoid nuking the enzymes or toasting the leaf.

Bob

Bob, its an interesting observation that I don't have noticeable ammonia in my kiln @ 124-130F with condensing humidity. However, with the bagged tobacco it is very pungent - to the point of watering the eyes and nose. I don't know why it doesn't happen in my kiln, maybe there is something else going on (too much air flow for ammonia to accumulate possibly)? Even on the very small scale (the two hands of cigar tobacco) I noticed some warmth when sticking my hand in the bag - ambient temp at ~76F and around 81 in the bag according to my food thermometer.

I think you are right that the microbes play a minor role here, and its mostly due to the native enzymes. I also think that ammonia release is very important for achieving the "cigar" character, by raising the pH and allowing for more phenol/polyphenol oxidase activity to generate the spicy quinones. As far as the heat goes, I chose the garage as the curing place since its around 100f most of the time, and this is a temp ive seen referenced with a few cigar makers online. I think the higher temps may be denaturing the aminease enzymes, and that's why I don't get ammonia in my kiln.

Right now this is more of an experiment than a tried and true method, but the preliminary results are exciting enough for me to continue.

 

[deluxestogie]

One other thought about the burley. If it is white stem burley, then, unlike most other varieties of tobacco, it's color-curing is out of sync with its metabolic curing. Because of its chlorophyll defect, the color zooms to brown faster than the active metabolic alterations complete their job. So you might need to allow it to continue color-curing for a few weeks after it colors to brown, before moving it to the kiln.

Bob

[I am completely spoiled. I hang my leaf to air-cure in the shed, then check back in a year, to start stripping it for kilning.]

 

[ChinaVoodoo]

too much air flow for ammonia to accumulate possibly

I don't think that's it. My kiln leaves the tobacco in buckets and cracking the bucket doesn't reveal ammonia.

I am very interested in your experiment. I've only gotten cigar flavored cigar tobacco by making an andullo with fully cured tobacco.

There are those who automatically get cigar flavour and those who don't and I wonder if it is related to drying parameters. Your method appears to be warm and high humidity. 100° & 90+%

 

[billy]

does nobodys kiln smell like amonia? i only got rustiuca leaves right now but my kiln fridge runs between 125-128f, humidity isnt known at the moment kinda just put jars of water in there till it felt right. but anywho, when you open the door you gotta make sure your head is well out of the hot air swath or your gonna have a bad day.

 

[ChinaVoodoo]

does nobodys kiln smell like amonia? i only got rustiuca leaves right now but my kiln fridge runs between 125-128f, humidity isnt known at the moment kinda just put jars of water in there till it felt right. but anywho, when you open the door you gotta make sure your head is well out of the hot air swath or your gonna have a bad day.

People do. I have definitely read it on here.

 

[ChinaVoodoo]

I wonder if it's as simple as I don't fertilize enough and my leaf is low in protein.

 

[billy]

i wonder how much this is a science VS so many varying factors thats is practically a chaotic system, and you just sorta figure out what works for you. like for me i picked an early lower havana leaf and just hung it in 80f and 80% humidity for about a week till dark brown and rolled a cigar, no kiln or anything as a test. unlit it didnt smell like much of anything, perhaps since it was hanging in a wide open plastic room by itself. but smoking it definitely taste like cigar, if i bought it as a affordable cigar i would of been happy. was expecting some kind of awful if i didnt kiln it first

 

[ChinaVoodoo]

i wonder how much this is a science VS so many varying factors thats is practically a chaotic system, and you just sorta figure out what works for you. like for me i picked an early lower havana leaf and just hung it in 80f and 80% humidity for about a week till dark brown and rolled a cigar, no kiln or anything as a test. unlit it didnt smell like much of anything, perhaps since it was hanging in a wide open plastic room by itself. but smoking it definitely taste like cigar, if i bought it as a affordable cigar i would of been happy. was expecting some kind of awful if i didnt kiln it first

I'm curious. What is your fertilization, and soil like?

 

[billy]

I'm curious. What is your fertilization, and soil like?

about 35% sand 45% silt 20% clay
in 1k sq/ft terms
did about 4lbs urea, 15 wheelbarrows homemade compost and 50lb alfalfa pellets
this was ~2 weeks pre planting
then 5lbs AN spread over a few 2 week intervals after planting

could of linked my grow blog but this is about what you could deduct
also bear in mind im new and have no idea what im doing

 

[ChinaVoodoo]

View attachment 37916 View attachment 37917
about 35% sand 45% silt 20% clay
in 1k sq/ft terms
did about 4lbs urea, 15 wheelbarrows homemade compost and 50lb alfalfa pellets
this was ~2 weeks pre planting
then 5lbs AN spread over a few 2 week intervals after planting

could of linked my grow blog but this is about what you could deduct
also bear in mind im new and have no idea what im doing

Hmm, that's about 50-60% more nitrogen than I apply. And my soil is probably mostly loam and clay. Correction, humus, not loam.

 

[deluxestogie]

When you include a different plant species, N. rustica, in the discussion of comparisons, it really is confusing. I'll just consider Nicotiana tabacum.

Confounding factors:

• choice of tobacco variety *****
• seedling size at transplant *****
• timing of transplant *****
• local climate
• seasonal weather *****
• sun angle
• daylight period
• soil types
• fertilizer used
• fertilizer usage rate
• fertilizer application timing
• watering/rain timing and quantity
• topping timing *****
• degree of maturity at harvest *****
• color-curing conditions *****
• color-curing duration *****
• aging prior to kilning
• aging conditions prior to kilning
• kilning temperature/humidity/ventilation *****
• post-kiln aging duration
• post-kiln aging conditions

[***** = Bob's notion of really significant factors. If you can grow nice tomatoes, then only these marked factors will determine the quality of your finished tobacco.]

Consider that minimally educated farmers with no standardized soil supplements (or Ag. Extension Service advice) to utilize, and only hearsay understanding of how to plant, grow and cure tobacco have done it successfully for centuries (if not millennia). They didn't even have digital controllers and a growers' Internet forum! It's clearly easier in tobacco-friendly geography, but possible over much of the cultivable world.

Bob

 

[Hayden]

i wonder how much this is a science VS so many varying factors thats is practically a chaotic system, and you just sorta figure out what works for you. like for me i picked an early lower havana leaf and just hung it in 80f and 80% humidity for about a week till dark brown and rolled a cigar, no kiln or anything as a test. unlit it didnt smell like much of anything, perhaps since it was hanging in a wide open plastic room by itself. but smoking it definitely taste like cigar, if i bought it as a affordable cigar i would of been happy. was expecting some kind of awful if i didnt kiln it first

In the videos i have seen from tobacco harvesting, they harvest the leaves quiet green.
Its quiet greener than what i am comfrontable at the moment because its my first year and in addition to that i think i need more nitrogen for my plants but maybe your observation has something to do with it.

In this state of greenes i woulden´t get the sellery crack if i would bend it down.

 

[deluxestogie]

In that stock photo, you can not see the tips of the leaves very clearly, but those that are visible appear to show a bit of yellowing.

Bob

 

[PressuredLeaf]

I don't think that's it. My kiln leaves the tobacco in buckets and cracking the bucket doesn't reveal ammonia.

I am very interested in your experiment. I've only gotten cigar flavored cigar tobacco by making an andullo with fully cured tobacco.

There are those who automatically get cigar flavour and those who don't and I wonder if it is related to drying parameters. Your method appears to be warm and high humidity. 100° & 90+%

Its curious you should mention drying parameters, I suspect that is a big part of it. I've noticed that when I string up the yellowing leaves, after a while some of the leaves in the middle of the bunch can give off ammonia, but the ones at the edge don't. I have to do a lot of shuffling with my leaf bunches because there is a fine line between high humidity for drying, and rotting leaves and very close to that line seems to be where I first noticed the ammonia. I suspect slow drying is needed because as the leaf dies, chlorophyll is degraded, starches as sugars are consumed, and as a last ditched effort proteins are catabolized into carbs with release of ammonia. For proteins to be catabolized (what I would guess would be the very last process before cell death), they need to be hydrolyzed into smaller peptides and eventually to amino acids. So my thought is, if the leaf dies nice and color cured before the proteins can be fully broken down into amino acids, there is no easy was to release ammonia since the proteins are much to large for the enzymes to efficiently degrade. The consequence of that is leaf that doesn't burn well (black ash due to protein not burning just carbonizing), and you don't get ammonia release during the aging because the enzymes cant act on the big ol insoluble peptides.

Like I mentioned, the first ammonia leaves I bagged up were already in case from there own natural moisture so they never dried out. This second time around with the corojo I used a hand of fully dried color cured leaf, I wonder if the ammonia production will happen?

For our friends in very humid environments, I think a lot of this is taken care of naturally.

 

[PressuredLeaf]

Quick update, I have three trash bags of leaves sweating.

1. The original bag that has a hand of piloto and corojo
2. A new bag of all corojo
3. A new bag of all piloto

Bag one has been sitting in the garage for a while. Since the ammonia release has been very constant I thought I would put the bag in the kiln to see what happens. 1st day in the kiln was at 102F and there was tons of ammonia. Next day was at 106f and there is so much ammonia it hurts you eyes an mucosa. I'm goin to slowly ramp the temp to see what happens.

Bags 2 and 3 have been in the garage for about 2 or three days. Both have hints of ammonia, and a very irritating type of smell (hard to describe, but its irritating and makes one want to sneeze, maybe it is just ammonia covered up by the raw tobacco smell?). I took the leaves out of each bag to check the case and look for mold. No mold in either, but the humidity wasn't even. Leaves on the bottom of the bag in higher case were quite ammonical, while the higher-dryer ones were not. So I shook out the lower hands, misted the dryer hands and re-stacked by putting the lower wet hand on top of the drier hands.

Other observations:
Leaves from bag one feel toothy and almost chalky to the touch, while leaves from bag 2 and three are very sticky.

Hopefully with the increased moisture, ammonia release will kick off with bags 2 and 3. If not, that may suggest that the natural leaf moisture needs to be preserved for ammonia of gassing.

 

[Tobaccofieldsforever]

So far as I can determine from the physics and biochemistry of pilon fermentation, there are two factors at work. This assumes the leaf has already color-cured to brown, and is not appropriate for green or yellow leaf.

First, the weight of the pilon may apply tons of weight to the floor supporting the entire pilon, but the pressure per square inch on the tobacco at the bottom of the pilon is negligible (certainly in the low single digits psi). [Picture a pile of tobacco that is 1"x1" and 5' tall.] Further, it is in the center of the pilon, not at the bottom, where the temperature rises most. Instead, the dimensions of the pilon seem to be acting mostly as thermal insulation. That is why it needs to be repeatedly torn down and rebuilt, so that eventually all the leaf has rotated to the center, where the temperature rises the most.

Secondly, the source of the temperature rise is the exothermic reaction of intrinsic leaf enzymes that are oxidizing carbohydrates and (the source of the ammonia) albuminous proteins. As the amino groups are cleaved from the proteins, ammonia molecules are created. Microbial studies of this fermentation process shows all sorts of microbes, BUT...the microbes are least numerous when the fermentation is most active. So the bugs are there incidentally, and are suppressed by the heat of the enzymatic oxidative process, and likely play little role in this part of the story.

Key to active oxidation is sufficient moisture (low case seems to be sufficient). Since the rate of enzymatic reactions increases exponentially with the ambient temperature (up to the temp at which the enzyme itself is destroyed), the thermal insulation of the center of a pilon is where most of the action happens. A long-stem thermometer--like a compost thermometer--is passed through a metal tube to the very center of a pilon, to monitor the temp. Once it reaches about 128°F at the center of the pilon, the pilon is broken down and rebuilt. The process is repeated until the temperature rise becomes negligible.

So you need heat (to save years of patient waiting) and moisture. That is the entire purpose of a tobacco kiln. The insulated kiln provides the heat evenly to all the tobacco inside it--regardless of how much or how little tobacco is in there, and the moisture keeps the oxidation going. Unlike flue-curing, you start with fully color-cured (brown) leaf, try to stay above 122°F to prevent mold growth, and stay below about 130°F, to avoid nuking the enzymes or toasting the leaf.

Bob

First off, I do not smoke cigars and have nearly no hands on experience growing cigar leaf. This post piqued my interest because I was reading a book last night "Growing and Processing Tobacco at Home - A Guide for Gardeners" by Jim Johnson. There is another book inside this book (haha) "Tobacco: Easier Than You Thought" by A.N. Daly. In Daly's portion of the book there are instructions on building wooden kilns, kilning, curing, fermenting etc... And although this is all laid out for the reader, Daly still suggests home growers (p. 58 "Fermenting Tobacco for Cigar Wrappers) use small "piles" to ferment/cure their cigar wrapper leaf. He suggests you start with leaf that has about 15 to 20% moisture content. I found this interesting because a kiln SHOULD replicate what the pilon method achieves more efficiently (eliminating the need to break down and rebuild the pile) and to the exact same end. However, for some reason, it is still suggested home growers use small piles to ferment their cigar wrapper leaf. I am interested in the chemistry behind his reasoning.

 

[Tobaccofieldsforever]

I apologize for the small text. It was the best I could do at the moment. You can zoom in on the text if you click on the image and open it in another window. Then click on the magnifying glass with a plus sign in the middle of it in upper right hand corner.