Flue Curing: Possibilities of irregular curing due to leaf position

[FALaholic]

I was thinking. If Virginia is primed, and lower leaves will be curing sooner than upper leaves. How does one set the curing schedule to cure evenly?

Lower leaves will be in the flue sooner and will have already started. By the time the upper most leaves are placed into the flue, one could be on their 2nd or 3rd stage of flue curing.

 

[johnlee1933]

I was thinking. If Virginia is primed, and lower leaves will be curing sooner than upper leaves. How does one set the curing schedule to cure evenly?

Lower leaves will be in the flue sooner and will have already started. By the time the upper most leaves are placed into the flue, one could be on their 2nd or 3rd stage of flue curing.

I believe the idea is to put all of one prime in the chamber and run it. A week later it will be finished ready for another run. To my knowledge partial loading's are not done.

 

[FALaholic]

Thank you. I was thinking in too small of a calendar schedule. You are right it should only take a week or two to flue cure, and by then the next primings will be ready to be cured.

 

[deluxestogie]

...should only take a week or two to flue cure...

Flue-curing nominally takes 5 days. Mine has been running 7 days (4 days of yellowing in the Cozy Can).

Bob

 

[FALaholic]

Thats it? That is fast.

 

[johnlee1933]

Flue-curing nominally takes 5 days. Mine has been running 7 days (4 days of yellowing in the Cozy Can).

Bob

Bob, Is there a downside to flue curing varieties that are NOT normally flue cured?

John

 

[deluxestogie]

John,
Once a leaf is flue-cured, it will age very slowly thereafter, since the most active enzyme, and oxidase, is destroyed. For flue-cure varieties, the objective is to lock in the light color, the pH and the sugar.

Among flue-cure varieties, I see dramatic differences in the quality of the flue-cured product. Paris Wrapper and Silk Leaf never developed the crepe-like texture that is easy to get with VA Bright. And they were consistently darker.

Burley starts out with a different chemical composition (compared to flue-cured varieties). I'm not sure what you'd get.

For some Oriental varieties, this works out fairly well. For cigar leaf, for example, flue-curing may leave you with leaf that requires many years to finish. I've never tried it.

I did flue-cure some Xanthi-Yaka 18a. It is alright for a pipe blender, but not nearly as nice as either air-cured Xanthi or the traditional sun-cured Xanthi. The Çelikhan also doesn't do all that well when flue-cured.

Another unanswered question is what happens if you flue-cure a cigar variety, then kiln it.

I think that some of the thick-leaved Hungarian varieties might flue-cure well, but again, I haven't tried it.

Bob

 

[johnlee1933]

John,
Once a leaf is flue-cured, it will age very slowly thereafter, since the most active enzyme, and oxidase, is destroyed. For flue-cure varieties, the objective is to lock in the light color, the pH and the sugar.

Among flue-cure varieties, I see dramatic differences in the quality of the flue-cured product. Paris Wrapper and Silk Leaf never developed the crepe-like texture that is easy to get with VA Bright. And they were consistently darker.

Burley starts out with a different chemical composition (compared to flue-cured varieties). I'm not sure what you'd get.

For some Oriental varieties, this works out fairly well. For cigar leaf, for example, flue-curing may leave you with leaf that requires many years to finish. I've never tried it.

I did flue-cure some Xanthi-Yaka 18a. It is alright for a pipe blender, but not nearly as nice as either air-cured Xanthi or the traditional sun-cured Xanthi. The Çelikhan also doesn't do all that well when flue-cured.

Another unanswered question is what happens if you flue-cure a cigar variety, then kiln it.

I think that some of the thick-leaved Hungarian varieties might flue-cure well, but again, I haven't tried it.

Bob

Thank You Since I'm interested in wrapper I guess there's no reason to consider a cozy can.

John

 

[DGBAMA]

What would be the highest practical drying temperature without "flue curing", like for speeding up the drying of stems? From what I am learning about flue curing vs kilning, seems like 125-130?

 

[DonH]

What would be the highest practical drying temperature without "flue curing", like for speeding up the drying of stems? From what I am learning about flue curing vs kilning, seems like 125-130?

If you're drying stems and not fermenting, the important thing is to not humidify. 130 at low humidity would definitely dry the stems. As to how high you can go you would want to stay below the temp that the enzymes get killed so that you can still age or ferment it after the stems are dry. Bob can correct me but I think it's somewhere in the 140-150 range.

 

[leverhead]

What would be the highest practical drying temperature without "flue curing", like for speeding up the drying of stems? From what I am learning about flue curing vs kilning, seems like 125-130?

As long as the leaf lamina is still moist, don't go over 105 F. Once it's dry, stay below 149 F. Probably 140 F to leave room for error. I did a graph of my first flue-cure run this year, the blue line is drying potential. Even at 140 F the amount of moisture air can pick up substantial. At the end of flue-curing it becomes enormous and dries thumb sized stems in under two days.

 

[workhorse_01]

So for my wrapper varieties it's best to air cure? Then sweat in a kiln? I know what Amax sent me made me want to eat it for desert. I'm about 60% air cure this year. My flue cure box is about together and it will have complete heat and humidity control. I cant let amax have all the fun!

Thank You Since I'm interested in wrapper I guess there's no reason to consider a cozy can.

John

 

[DGBAMA]

Don & Leverhead, perfect and thank you. I don't have enough hanging space, so if I can use the kiln to yellow and dry the leaf for storage without hurting the natural aging enzymes this is exactly what I need. I can then go back later and kiln or flue cure as desired. First priority is getting leaf colored, dry, and storable without hurting the leaf where it cannot continue to age naturally.

 

[workhorse_01]

Bama, I think you are right to get the leaf stable first, that's what i'm doing as well.

Don & Leverhead, perfect and thank you. I don't have enough hanging space, so if I can use the kiln to yellow and dry the leaf for storage without hurting the natural aging enzymes this is exactly what I need. I can then go back later and kiln or flue cure as desired. First priority is getting leaf colored, dry, and storable without hurting the leaf where it cannot continue to age naturally.

 

[leverhead]

First priority is getting leaf colored, dry, and storable

If you follow that schedule up to 140 F, you may end up with a bright leaf that will darken with age. It may take two weeks to do it.

 

[Knucklehead]

I can then go back later and kiln or flue cure as desired. First priority is getting leaf colored, dry, and storable without hurting the leaf where it cannot continue to age naturally.

I know you know this but just to clarify for the new guys: You color cure the leaf by air drying before kilning, but green leaf is flue cured. You can't go back and flue cure leaf that has been color cured by air drying.

 

[workhorse_01]

Yep, I think he ment to sweat it or kiln it later. Don't forget for the new guys, that if leaf dries green, it will always be green.

I know you know this but just to clarify for the new guys: You color cure the leaf by air drying before kilning, but green leaf is flue cured. You can't go back and flue cure leaf that has been color cured by air drying.

 

[deluxestogie]

One added factor. The color of color-cured leaf will be lighter if yellowed leaf is then rapidly dried in low humidity. The longer it takes to go from yellow to brown, and the higher the humidity during that interval, the darker the leaf will become. I have no idea what differences that makes to flavor and aroma.

On a similar matter, white-stem burleys, in particular, need to be allowed to naturally brown (rather than accelerating the process in a heated curing chamber), because the chemical processes of breaking down carbs and proteins is not synchronized with the timing of yellowing. In most other varieties, the leaf can be dried once it has yellowed. That is to say, white-stem burley looks well yellowed before the chemical breakdown processes are complete. If you try to speed them up, you will end up with beautiful leaf that is loaded with starches and proteins, and chars, rather than burns.

Bob

 

[workhorse_01]

Thanks for that DS. I'll just let the Hi Burley 21 take their time then.

One added factor. The color of color-cured leaf will be lighter if yellowed leaf is then rapidly dried in low humidity. The longer it takes to go from yellow to brown, and the higher the humidity during that interval, the darker the leaf will become. I have no idea what differences that makes to flavor and aroma.

On a similar matter, white-stem burleys, in particular, need to be allowed to naturally brown (rather than accelerating the process in a heated curing chamber), because the chemical processes of breaking down carbs and proteins is not synchronized with the timing of yellowing. In most other varieties, the leaf can be dried once it has yellowed. That is to say, white-stem burley looks well yellowed before the chemical breakdown processes are complete. If you try to speed them up, you will end up with beautiful leaf that is loaded with starches and proteins, and chars, rather than burns.

Bob