Whole Leaf Tobacco

Midribs in curing

Bex

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#1
I'm having a debate with a fellow 'curer'....both of us attempting our flue curing with varying results. He removes the midrib prior to doing his flue cure, as he advises they are garbage, unnecessary, etc. I disagree. Not only can I not find any commercial (or 'private') grower that does this, I also assume that this knocks off the temperature schedule, relative humidity, timing, etc., of a flue cure run, so that the schedule that I attempt to go by, becomes somewhat meaningless. Without the midrib, he is able to 'dry' his leaf before he even hits 120F, which to me, would still be in wilting.
I can't find any scientific information about what the midrib actually does during the flue cure process (although I imagine it keeps the leaf alive, feeds it, etc., while the flue curing process is initially started)....I'm hoping that someone can direct me to some scientific link that proves (or disproves) my point - being that commercial curers would not spend all the additional time, energy, cost, etc., to maintain the midrib during curing, if it wasn't necessary....Thanks!!
 

Alpine

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#2
I suppose that commercial growers don't take the midribs off for two reasons: first tobacco is sold by weight, second Big Tobacco throws everything in commercial cigs, and midribs make volume. And, IIRC, at least one member of. The forum (Knucklehead?) suggested that midribs add flavor. Just my 0.02 €

pier
 

DistillingJim

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#3
Personally, I find the midrib useful simply as a secure way to hook the leaf for hanging
 
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#4
I toss anything that doesn't look appetizing, but I do smoke most of my mid ribs. I find it slows the burn and cools the smoke. There's no discernable flavor problem. The biggest hurdle to get over is cutting technique so that you don't end up with long pieces of it. I always cut perpendicular. It ends up looking like a little bird's eye in the shred.

This is before slicing, but you can see the light "c" shapes? No big deal, right?
IMG_20170808_222723255~3.jpg
 

deluxestogie

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#5
Personally, I find the midrib useful simply as a secure way to hook the leaf for hanging
I agree with this idea. Although it is true that Big Tobacco uses even the stems (after flattening and vacuum "expansion"), handling tobacco that has no stem presents labor and logistical issues.

I doubt that the presence of the stem during flue-curing has any significant effect on the curing of the lamina. Regardless, if you don't ramp the temperature above (at least) 149ºF, then the primary oxidizing enzyme within the lamina is not denatured, and the character of the finished tobacco will change much more rapidly with time. That is to say, you will lose sugars more rapidly.

Bob
 

DistillingJim

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#6
This may be an appropriate place to ask this - I once heard that the midrib was traditionally taken and used for snuff. Can anybody verify or discredit this?
 

deluxestogie

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#7
I don't know about snuff tradition, but I have read in a number of discussions of its use in snuff. Although stems burn just fine, they usually contain a lower concentration of nicotine than do lamina tissues.

Bob
 

OldDinosaurWesH

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#8
According to my source (take that for what you will) the midribs are used by the big tobacco companies to make "Mother Liquor" which is then sprayed as a liquid on the tobacco as it is being processed. Or so I've been told...

Wes H.
 

Bex

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#9
Thanks for the responses! In some of my reading, I had read that during during curing, you wanted to keep the leaf 'alive' during the chemistry process. Wouldn't the midrib assist in this? I now understand the issue about the weight of the leaf, as well - when I remove my midrib for shredding, I lose a good 25% or more of the weight that I have put aside to shred. With regard to ease of hanging, some time ago I saw a video out of Bulgaria - they had harvested the leaf, and lain all the leaf down in a huge 'bunch' in some kind of rack, where they then secured the leaf in place by basically clamping it into the rack - so no hanging, etc. But certainly that weight issue is very logical.
By the way, China, when I used to use my Teck 1, which naturally shredded the midrib perpendicularly, I never wasted anything. I've tried doing this with Lucas' shredder, where you try to lay the leaf on its side as you shred - a bit more problematic. I've even tried removing the midrib and pulverising it in a coffee grinder, and adding the bits like shaking salt over the shredded leaf...lol. Of course, I'm smoking cigarettes, so the little 'bird's eyes' are a bit more intrusive in the blend.
And thanks, Stogie, with regard to the 149F (65C) advice. My friend ends his run much lower than that, so that info is good to know.....
 

Hasse SWE

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#10
This may be an appropriate place to ask this - I once heard that the midrib was traditionally taken and used for snuff. Can anybody verify or discredit this?
I can't give you a answer one that but I can tell you that company like skruf and Swedish match ain't take extra midribs' in their products (But both those companies have told me that they use the hole plant in their production of oral-snuff). But I can't also tell you that "make your own Snus kit" are pretty common in Sweden and most of those are grind tobacco spill from Cigarettes, pipe tobacco or cigar industries and some people say that those are mostly made of midribs' but the companies how sell them ain't saying that..
 

deluxestogie

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#11
In some of my reading, I had read that during during curing, you wanted to keep the leaf 'alive' during the chemistry process. Wouldn't the midrib assist in this?
Of course, you are correct. I sometimes forget about that yellowing phase. I suppose that in a humid yellowing environment, a stemless leaf might yellow fast enough to not dry green, but I would worry about that. Once the wilting phase is entered, the lamina are killed, so the stem is just a hanger.

Bob
 

Bex

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#12
Hmmm....excuse my ignorance, but if the lamina is killed during wilting, why then do you need to hit the higher temps of 149F to 'denature the primary oxidizing enzyme' (whatever that actually means....LOL) ???
 

deluxestogie

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#13
There are a bunch of biochemical changes that happen in living leaf, while it is yellowing. Once the leaf is dead (which happens rapidly in the wilting stage), there are two oxidizing enzymes that persist, and are still active in the now dead leaf. They are responsible for the "aging" that transforms raw, brown tobacco into something nice. The most active of these persistent enzymes is denatured (cooked, and no longer functional) at 149ºF. The much less active oxidizing enzyme (much slower in its action) can survive up to about 191ºF, and usually survives flue-curing.

The trick of flue-curing is to lock the chemistry of the leaf in a particular state (one we like to smoke), then throw away the key (that is, denature the main enzyme). If the main oxidase enzyme persists, then that happy "flue-cured" state slips away with aging.

Bob
 

CowboyTed

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#14
There are a bunch of biochemical changes that happen in living leaf, while it is yellowing. Once the leaf is dead (which happens rapidly in the wilting stage), there are two oxidizing enzymes that persist, and are still active in the now dead leaf. They are responsible for the "aging" that transforms raw, brown tobacco into something nice. The most active of these persistent enzymes is denatured (cooked, and no longer functional) at 149ºF. The much less active oxidizing enzyme (much slower in its action) can survive up to about 191ºF, and usually survives flue-curing.

The trick of flue-curing is to lock the chemistry of the leaf in a particular state (one we like to smoke), then throw away the key (that is, denature the main enzyme). If the main oxidase enzyme persists, then that happy "flue-cured" state slips away with aging.

Bob
It's interesting how much of the science is shared in my hobbies. When I brew beer and liquor, I'm concerned with the life cycle of enzymes too. There are enzymes produced by grains that help break down the starches and convert them into sugars as we brew the wort or mash. If we raise the temperature at a certain point in brewing the grains, it denatures the enzymes and locks in the flavor profile at that point, which will influence the flavor of the finished beer or whiskey after fermentation and distilling.

I brew a variety of Chinese whiskey (Baijiu) where they "brew" and ferment the wort at room temperature. The cooler temps carry the active enzymes into the fermentation stage so that they continue breaking down starches for months. The flavor in the finished whiskey is decidedly "dry" because there are no sugars left after the enzymes finally convert them all to sugars and the yeast converts the sugars to alcohol. That's the reason Americans usually don't like the stuff: we are accustomed to bourbon and corn whiskeys, which denature the enzymes before fermentation even starts, and thus preserve a lot of the sweet flavors from the grain. The Chinese find our whiskey to be too sweet, because their method of making whisky uses all the starch to make alcohol, instead of saving some of the starch for its sweet flavors.
 

burge

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#15
Sticks and stems add to the flavor of tobacco. I had some flue cure and decided I want to try some stems. To my tastes it tasted bland however they were kind of sweet. I would suggest that the stem provides sugar to the leaf itself.
 

deluxestogie

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#16
Sugars are created within the laminar cells by photosynthesis, and is passed on to the roots via the stem and stalk, for nourishment. It originates in the leaf tissues. That's the great achievement of photosynthetic plants--to turn water and CO[sub]2[/sub] into sugar, using sunlight as a power source.

Bob
 

Bex

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#17
There are a bunch of biochemical changes that happen in living leaf, while it is yellowing. Once the leaf is dead (which happens rapidly in the wilting stage), there are two oxidizing enzymes that persist, and are still active in the now dead leaf. They are responsible for the "aging" that transforms raw, brown tobacco into something nice. The most active of these persistent enzymes is denatured (cooked, and no longer functional) at 149ºF. The much less active oxidizing enzyme (much slower in its action) can survive up to about 191ºF, and usually survives flue-curing.

The trick of flue-curing is to lock the chemistry of the leaf in a particular state (one we like to smoke), then throw away the key (that is, denature the main enzyme). If the main oxidase enzyme persists, then that happy "flue-cured" state slips away with aging.

Bob
Thanks for this. There is so much science involved with this, it's difficult for old heads to remember. That's probably why I don't play bridge...LOL....too many 'rules' to know....
 
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#18
I am totally new to this topic but was wondering if soaking the yellowed leaves in hot water (150f) would do the same as traditional flue curing as it would denatured the first enzyme but allow the second to continue to age the leave during air curing
 

Bex

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#20
I can’t imagine soaking the leaf at that point (other than ruining the tobacco). When doing flue curing, at 150F, you are already into the ‘stem drying’ phase, having already gone through leaf drying, and are practically at the end of the flue curing process. You also normally stay at that temp for about 24 hours. How would you maintain that temp for that amount of time? I don’t know what ‘goodness’ would be washed away, but certainly it makes a somewhat complicated procedure even more complicated. IMHO. :)
 
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