Buy Tobacco Leaf Online | Whole Leaf Tobacco

Vacuum curing?

Status
Not open for further replies.

Aaron

Well-Known Member
Joined
May 2, 2012
Messages
450
Points
0
Location
Canon City CO
Let me start by saying that the science of this is way above my head! I've been wondering if its possible to strip the ammonia off of color-cured leaf by placing it in a vacuum chamber. I understand that I make a lot of assumptions here, and I'm not positive that all my figures, conversions, and calculations are correct. By searching the internet I've found that the vaporization pressure of ammonia is about 14.5 inHg. At my elevation of 5000ft the atmospheric pressure is about 25 inHg. If I apply around 15 inHg of vacuum to a container that should put my inside pressure at about 10 inHg thereby vaporizing the ammonia. I really don't know if the ammonia in tobacco is even in a form that can be vaporized in the first place. I made a small tester earlier while I was home for lunch. I used a pickle jar, attached a piece of tubing to lid and put a vacuum check valve in line so it would hold the vacuum inside, then used a hand pump to put a vacuum on it. I left a vacuum on the jar for about 10 minutes then opened it to exchange the air and then applied a vacuum again for another 10 min or so. Oh ya, I forgot to mention that I had some color-cured suckers that I put in the jar for this test. After the second round of vacuum I took the lid back off blew some fresh air in the jar again and then used the old sniffer test to smell the leaf. It may be all my imagination but it seemed like the leaf was smelling sweeter and had less of a funky smell.

My question now is... Am I just an ignorant moron for trying this? Is this even possible or advisable? I know there are several members here that will understand this way better than me. Any thoughts?

Aaron:confused:
 

johnlee1933

Moderator
Founding Member
Joined
Aug 21, 2011
Messages
3,970
Points
0
Location
Near Danbury, CT
Nope you're not a moron. Anyone who asks such a question is thinking. I spent several years of my life with high and low vacuum. I assume your VP number fo ammonia is correct. If it is AND if it is pure ammonia you are dead on. I don't know enough about tobacco to say if the ammonia is all there or if it is generated by the curing process. If that is the case it seems to me you might be removing other stuff as well as the ammonia you want to remove.

DeluxStogie is pretty savvy about tobacco chemistry so he may jump in here and help a bit or maybe Smokestack.

John
 

deluxestogie

Administrator
Staff member
Joined
May 25, 2011
Messages
23,931
Points
113
Location
near Blacksburg, VA
The underlying process of color-curing and kilning is not the "removal" of ammonia, but rather the breakdown of nitrogen-containing compounds. The ammonia that comes off a tobacco leaf during color-curing and kilning is not lying around inside the leaf, waiting to leak out. It is created by the enzymatic breakdown of albuminous proteins and alkaloids. You smell it because it is being created. So I would say that negative pressure would not assist in any way.

Bob
 

Aaron

Well-Known Member
Joined
May 2, 2012
Messages
450
Points
0
Location
Canon City CO
Ah ha. I figured it couldn't be that easy. oh well. Thanks guys for saving me from further curiosity. :)
 

SmokeStack

Well-Known Member
Joined
Mar 28, 2012
Messages
368
Points
0
Location
Detroit area
I agree with Bob. Tobacco has no ammonia. The curing and fermenting processes degrade certain naturally occurring chemicals in the tobacco leaf. Ammonia is a chemical product that is generated by this degradation. Pretty much what Bob said.:)

If ammonia was present in tobacco leaves, then "vacuum curing" would be an excellent way to remove it. Good thinking!
 

Chicken

redneck grower
Founding Member
Joined
Aug 28, 2011
Messages
4,631
Points
83
Location
FLORIDA
so much science comes out of the equation,

of finishing baccy,,,

incredible,
 

johnlee1933

Moderator
Founding Member
Joined
Aug 21, 2011
Messages
3,970
Points
0
Location
Near Danbury, CT
Now you've got me wondering what would happen if you took cured smoke able leaves and put them in a 20" vacuum for an hour or two?

J
 

leverhead

Well-Known Member
Joined
Jan 16, 2012
Messages
3,204
Points
83
Location
Grimes County Texas
Now you've got me wondering what would happen if you took cured smoke able leaves and put them in a 20" vacuum for an hour or two?

J

Do you really want to know? I don't think it will do anything but dry it out. I've accumulated some cool toys over the years, a vacuum pump and a chamber 6" diameter X 36" tall.
 

Matty

Well-Known Member
Joined
Apr 1, 2012
Messages
698
Points
28
Location
Sherbrooke, Quebec
Hypothetically, all I think it would do is speed up the expulsion of such said gases from the leaf's cellular structure. More simply, it would be like a faster "airing out" of the leaf. I don't think it would have any effect on curing, as we all know curing is an enzymatic/chemical action. Try it, then we'll know ;)
 

johnlee1933

Moderator
Founding Member
Joined
Aug 21, 2011
Messages
3,970
Points
0
Location
Near Danbury, CT
Do you really want to know? I don't think it will do anything but dry it out. I've accumulated some cool toys over the years, a vacuum pump and a chamber 6" diameter X 36" tall.

I assume you're using a roughing pump like an Edwards or a Leybold maybe? What kind of a vacuum can you draw? I agree but like any low case tobacco you can re-hydrate it and see if the taste changes.

J
 

leverhead

Well-Known Member
Joined
Jan 16, 2012
Messages
3,204
Points
83
Location
Grimes County Texas
I assume you're using a roughing pump like an Edwards or a Leybold maybe? What kind of a vacuum can you draw? I agree but like any low case tobacco you can re-hydrate it and see if the taste changes.

J

It'll take it down more than 20", let me dig it out and check it out. What do you think, a Burley? Split the leaf down the middle, one half in the chamber, the other left alone?
 

johnlee1933

Moderator
Founding Member
Joined
Aug 21, 2011
Messages
3,970
Points
0
Location
Near Danbury, CT
It'll take it down more than 20", let me dig it out and check it out. What do you think, a Burley? Split the leaf down the middle, one half in the chamber, the other left alone?

That sounds good. If it is an oil roughing pump you might want to consider some cotton in the line to avoid possible oil taste on the leaf. If the pumping time is not too long it may not be a problem at all. You can check this by rubbing a clean dry finger on the inside of the chamber and seeing if it feels slick or oily.
Interesting test. Good luck.

J
 

leverhead

Well-Known Member
Joined
Jan 16, 2012
Messages
3,204
Points
83
Location
Grimes County Texas
That sounds good. If it is an oil roughing pump you might want to consider some cotton in the line to avoid possible oil taste on the leaf. If the pumping time is not too long it may not be a problem at all. You can check this by rubbing a clean dry finger on the inside of the chamber and seeing if it feels slick or oily.
Interesting test. Good luck.

J

It's an oil-less pump for sure, so no worries there. I've got some of FMGrowit's Burley and Dark air cured. Sounds like a plan!
 

BarG

Founding Member
Joined
Jun 23, 2011
Messages
4,997
Points
113
Location
Texas, Brazos Vally
One of the reasons I process what I can smoke in a week is because I have sealed cured processed whole leaf that smells great and sealed in pint size canning jars and 2-3 weeks later it will have an ammonia smell when opened. Not all varietys though and I wonder if the case of shreded leaf upon sealing has anything to do with it. My fermented de stemmed leaf sealed in 2 1/2 gallon ziplocks is much less noticiable even if sitting in sunlight through window.
 

workhorse_01

Well-Known Member
Joined
Apr 10, 2012
Messages
1,959
Points
0
Location
Waycross,Ga.
I think the vacuum pump will only dry the tobacco if you pull it to a 29" vacuum and leave it for a time (depending on the cfm of the pump) and how many microns you pull it down to. As far as if it's oiled or oilless I'm having trouble understanding why that would matter to the taste as your only expelling moisture not pumping it in the bag? If you leave the pump at 29" until you hit 500 microns you could eventually pull a near perfect vac. which means moisture boils. Couldn't you then open the bag , rehydrate, for a time then evacuate again and trick the tobacco in to thinking it was aged? The only thing the vacuum pump does is get you to 29" once there moisture begins to boil off naturally, but only if left in a 29" vac.
Do you really want to know? I don't think it will do anything but dry it out. I've accumulated some cool toys over the years, a vacuum pump and a chamber 6" diameter X 36" tall.
 

leverhead

Well-Known Member
Joined
Jan 16, 2012
Messages
3,204
Points
83
Location
Grimes County Texas
I never did get a round tuit. Maybe I ought to. At low pressures, oil will vaporize too and get all over everything. I don't think it would taste too good.
 

johnlee1933

Moderator
Founding Member
Joined
Aug 21, 2011
Messages
3,970
Points
0
Location
Near Danbury, CT
VACUUM 101

The atmosphere around us is composed of atoms and molecules of different gasses. While mostly nitrogen and oxygen there are measurable percentages of other gasses notably water, carbon dioxide and carbon monoxide to name a few. These atoms and molecules (hereafter called AIR) are in constant motion and have weight. Air moves. You can feel air against your skin. You can see that it's mass is great enough to pile up behind flags and trees and move them. Cram more air into a tank and you have high pressure. High just means it's more than what it would be if you did nothing. Vacuum is just the opposite. You suck air out of a tank in stead of cramming it in. A soft vacuum is one where very little of the air has been removed like a vacuum cleaner. As you suck more and more air out you get what is called a "hard" vacuum. Atoms and molecules of air are in constant motion banging against surfaces and each other all the time. Measuring pressure or vacuum is simply measuring how many are pushing on your measuring device. Lots equal high. Not as many equals low.

Funny things start to happen as you pump air out of a tank. The atoms that were banging against each other (and the walls of the tank, pipe, pump, etc.) are farther apart. That makes sense. There are less of them. Since there aren't as many to bang against each other they travel farther and farther before hitting something and bouncing. As vacuums get harder and harder the distance between collisions gets longer and longer. With truly hard vacuums this distance can be inches, feet, yards, even miles.

Let's change gears for a minute.

Things boil as a function of temperature and pressure. We'll use water as our example. The the same principles apply to everything. Water at room temperature and pressure evaporates (gives off) and condenses (takes back) molecules depending on how much water is already in the air (relative humidity.) As you heat the water or reduce the pressure more molecules go from liquid to gas. As you reduce the surrounding pressure the same thing happens. Even ice evaporates. (This is the principle behind freeze drying.) Very simply as you pump away molecules more will replace them till there is no more liquid water left.

Now we get to the nitty gritty.

The oil used to lubricate and seal moving surfaces on a vacuum pump evaporates like anything else. As a molecule evaporates from the inside of the pump it travels in a straight line till it hits something. There it either bounces or sticks. If this straight line (and bounces) go from the pump to the tank (vacuum chamber) oil molecules (lots of them) can and do go "up stream" from the pump. Enough of them bounce and then "stick" where you don't want them to foul the vacuum chamber. (Stink up your tobacco.)

Oil-less pumps are common and have problems of their own.

Truly high vacuums are achieved by using a variety of pumps working together.

I spent years of my life designing, building and operating high and ultra high vacuum systems. We evaporated gold, aluminum, nickle, chrome and other materials to coat mirrors and semiconductor parts. Chambers were built to permit electron beams to travel and expose integrated circuits for computers.

So the kicker is if you choose to use an oil sealed vacuum roughing pump and pump a pretty good vacuum oil molecules can get back to your leaf.

Finally, some time back DeluxeStogie wrote that the ammonia we smell during curing isn't inside the leaf but is being generated by the fermentation process. I don't see drying leaf in a vacuum as a part of the curing process.
 

workhorse_01

Well-Known Member
Joined
Apr 10, 2012
Messages
1,959
Points
0
Location
Waycross,Ga.
Ok john , I've been pulling vacuums for almost 30 years but I never understood it from an atomic point of view. LOL. Most hvac people around here think when they install a system all they have to do is pull that thing down to 30" and there done They just cant understand that first where we live were only going to get to about 29" florida and Georgia are very close to sea level. Second all the moisture doesn't magically disappear at 29". It begins to boil once you get there. I think I'm going to print this thread off and carry a copy around with me and every time I see one of the local idiots doing a change out I'll just go up and hand them a copy, maybe then 2 yrs after they do the job I wont have to try to fix it after the damage from moisture has been done! My 12 cfm JB pump has a check valve where my hose connects so it only pulls one way. My dad works for me and every time we get ready for the pump he says " Get big blue and lets suck some copper flat" Who did you work for ? Did you build scientific pumps, or hvac pumps?
VACUUM 101

The atmosphere around us is composed of atoms and molecules of different gasses. While mostly nitrogen and oxygen there are measurable percentages of other gasses notably water, carbon dioxide and carbon monoxide to name a few. These atoms and molecules (hereafter called AIR) are in constant motion and have weight. Air moves. You can feel air against your skin. You can see that it's mass is great enough to pile up behind flags and trees and move them. Cram more air into a tank and you have high pressure. High just means it's more than what it would be if you did nothing. Vacuum is just the opposite. You suck air out of a tank in stead of cramming it in. A soft vacuum is one where very little of the air has been removed like a vacuum cleaner. As you suck more and more air out you get what is called a "hard" vacuum. Atoms and molecules of air are in constant motion banging against surfaces and each other all the time. Measuring pressure or vacuum is simply measuring how many are pushing on your measuring device. Lots equal high. Not as many equals low.

Funny things start to happen as you pump air out of a tank. The atoms that were banging against each other (and the walls of the tank, pipe, pump, etc.) are farther apart. That makes sense. There are less of them. Since there aren't as many to bang against each other they travel farther and farther before hitting something and bouncing. As vacuums get harder and harder the distance between collisions gets longer and longer. With truly hard vacuums this distance can be inches, feet, yards, even miles.

Let's change gears for a minute.

Things boil as a function of temperature and pressure. We'll use water as our example. The the same principles apply to everything. Water at room temperature and pressure evaporates (gives off) and condenses (takes back) molecules depending on how much water is already in the air (relative humidity.) As you heat the water or reduce the pressure more molecules go from liquid to gas. As you reduce the surrounding pressure the same thing happens. Even ice evaporates. (This is the principle behind freeze drying.) Very simply as you pump away molecules more will replace them till there is no more liquid water left.

Now we get to the nitty gritty.

The oil used to lubricate and seal moving surfaces on a vacuum pump evaporates like anything else. As a molecule evaporates from the inside of the pump it travels in a straight line till it hits something. There it either bounces or sticks. If this straight line (and bounces) go from the pump to the tank (vacuum chamber) oil molecules (lots of them) can and do go "up stream" from the pump. Enough of them bounce and then "stick" where you don't want them to foul the vacuum chamber. (Stink up your tobacco.)

Oil-less pumps are common and have problems of their own.

Truly high vacuums are achieved by using a variety of pumps working together.

I spent years of my life designing, building and operating high and ultra high vacuum systems. We evaporated gold, aluminum, nickle, chrome and other materials to coat mirrors and semiconductor parts. Chambers were built to permit electron beams to travel and expose integrated circuits for computers.

So the kicker is if you choose to use an oil sealed vacuum roughing pump and pump a pretty good vacuum oil molecules can get back to your leaf.

Finally, some time back DeluxeStogie wrote that the ammonia we smell during curing isn't inside the leaf but is being generated by the fermentation process. I don't see drying leaf in a vacuum as a part of the curing process.
 
Last edited by a moderator:

johnlee1933

Moderator
Founding Member
Joined
Aug 21, 2011
Messages
3,970
Points
0
Location
Near Danbury, CT
My 12 cfm JB pump has a check valve where my hose connects so it only pulls one way. Who did you work for ? Did you build scientific pumps, or hvac pumps?
The check valve only works when gas is moving from hi to lo pressure. After a while there isn't enough air pressure to push the spring or lift the ball in the check valve. for HVAC applications they work fine. I worked for Bell Telephone Laboratories and then Perkin-Elmer Corp. Both of those jobs involved ultra high vacuum which is achieved by a combination of pumps starting with the type of pump you are used to. We called them "roughing" pumps to achieve a "rough vacuum", usually around 30" (760 mm). Of course we always talked in millimeters of mercury because there is then a consistent set of pressure terms. mm is 10 to the -3. Our ultra hi vacs were 10 to the -9 meters of mercury.

In retirement I ran a handyman business and fixed most everything. That included small AC's and fridges and freezers. I still have a set of gauges and transfer valves lying around here somewhere plus puncture valves to hook them up for a quick fix. I gave my roughing pump (a Cenco) away several years ago.

This is much too long and not tobacco but maybe we should swap lies over the phone some time.
 
Status
Not open for further replies.
Top