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Clean, Cool Smoke via Thermodynamics

mr t 59874

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                                                                             Clean, Cool Smoke via Thermodynamics

In over 40 years of producing smoked cheese, until now the basic principles of thermodynamics were understood, but not the complexities. Not knowing why , but it was known that it was what was needed to produce an exceptional product.

Smoke was cooled and cleaned as much as possible by whatever means and the cheese, or other product, was smoked to a desired taste and color. As I am a layman, the following is an attempt to explain it in layman’s terms.

Heat always flows from the higher-temperature substance, in our case, smoke, to the lower-temperature substance, including the fire box, the piping to the product chamber, the product chamber itself, and the product.

Note: A large surface area is ideal in order to cool, collect, and remove as many impurities as possible before entering the food chamber

.

Fact: A cold product will accumulate more impurities than a warm one, therefore, when cold smoking; cold smoke as close to ambient temperature as possible, this includes both the product and the smoke. This procedure will then allow longer smoking periods without an off taste.

Photo examples in my blog. http://smokingfoodwithmrt.com/smoke-direct-vs-indirect

When cold smoking, use a product and smoke, as close to ambient temperature as possible, the heavy impurities will collect on all the surfaces rather than being drawn primarily on the cooler product being smoked. The narrow difference in temperature also prevents the accumulation of moisture, whether visual or not, on the products surface, which would then collect more impurities, picture moisture collecting on the inside of a cold window. Warm moist air being exposed to a cold window produces condensation. This explains why those smoking a cold product using warm smoke will experience a stronger smoke flavor in a shorter amount of time than those smoking for longer periods with a product and smoke closer in temperature to each other.

Although the timing will differ, this should help explain how different colors and densities of smoke can be used in your favor to smoke unlimited products.

Note: Smoke flavor should meld with the flavors of the product being smoked, not overpower them.

Related threads:

http://www.smokingmeatforums.com/t/139474/understanding-smoke-management-updated-12-08-14

http://www.smokingmeatforums.com/t/...-have-a-new-smoker-how-to-optimize-your-smoke

http://www.smokingmeatforums.com/t/123130/mr-ts-smoked-cheese-from-go-to-show-w-q-view

http://www.smokingmeatforums.com/t/123840/my-cold-smoking-options-w-q-view

http://www.smokingmeatforums.com/t/...r-smoke-when-smoking-cheese-or-other-products

Tom
 
Last edited:

driedstick

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GREAT INFO Tom,,, will help me alot in future smokes. Great link,,, very informative 

Have a great day. 
 

forluvofsmoke

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                                                                             Clean, Cool Smoke via Thermodynamics

In over 40 years of producing smoked cheese, until now the basic principles of thermodynamics were understood, but not the complexities. Not knowing why , but it was known that it was what was needed to produce an exceptional product.

Smoke was cooled and cleaned as much as possible by whatever means and the cheese, or other product, was smoked to a desired taste and color. As I am a layman, the following is an attempt to explain it in layman’s terms.

Heat always flows from the higher-temperature substance, in our case, smoke, to the lower-temperature substance, including the fire box, the piping to the product chamber, the product chamber itself, and the product.

Note: A large surface area is ideal in order to cool, collect, and remove as many impurities as possible before entering the food chamber

.

Fact: A cold product will accumulate more impurities than a warm one, therefore, when cold smoking; cold smoke as close to ambient temperature as possible, this includes both the product and the smoke. This procedure will then allow longer smoking periods without an off taste.

Photo examples in my blog. http://smokingfoodwithmrt.com/smoke-direct-vs-indirect

When cold smoking, use a product and smoke, as close to ambient temperature as possible, the heavy impurities will collect on all the surfaces rather than being drawn primarily on the cooler product being smoked. The narrow difference in temperature also prevents the accumulation of moisture, whether visual or not, on the products surface, which would then collect more impurities, picture moisture collecting on the inside of a cold window. Warm moist air being exposed to a cold window produces condensation. This explains why those smoking a cold product using warm smoke will experience a stronger smoke flavor in a shorter amount of time than those smoking for longer periods with a product and smoke closer in temperature to each other.

I had never really thought about that way, but, if you consider what happens with refrigeration equipment, or, air conditioners, the humidity in the air is condensed at (you guessed it) the condenser (the coldest place the air passes through enroute to the place where it provides it's actual benefit). Anything in the stream of the smoke that is colder than ambient temp will condense moisture, and more smoke...makes perfect sense. Cold product in a warm stream of smoke will simply do just as a condenser in a refrigeration or A/C unit. Of course, those us lucky enough to be in an area with low relative humidity (15-20% is normal here, 10% is not unheard of) have a little extra going in our favor, as there can be considerably less water vapor condensation inside our smoke chamber.

Although the timing will differ, this should help explain how different colors and densities of smoke can be used in your favor to smoke unlimited products.

Note: Smoke flavor should meld with the flavors of the product being smoked, not overpower them.

And that is the defining characteristic...the moment you first smell and taste your product...which determines success or fail.

Related threads:

http://www.smokingmeatforums.com/t/139474/understanding-smoke-management-updated-12-08-14

http://www.smokingmeatforums.com/t/...-have-a-new-smoker-how-to-optimize-your-smoke

http://www.smokingmeatforums.com/t/123130/mr-ts-smoked-cheese-from-go-to-show-w-q-view

http://www.smokingmeatforums.com/t/123840/my-cold-smoking-options-w-q-view

http://www.smokingmeatforums.com/t/...r-smoke-when-smoking-cheese-or-other-products

Tom
Thanks going out to you again for sharing your wisdom, Tom!!!

Eric
 

johnmeyer

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Joined Nov 19, 2015
Mr. T helped me improve my cold smoking technique and today, by following his advice in this thread and elsewhere, I had my first successful cheese cold smoke. I think the things which made the biggest difference compared to my earlier failures were:
  1. Putting the AMNPS in an external "mailbox mod." I designed my own mailbox mod and created an external smoking enclosure which has far more surface area than the typical mailbox. This increases its ability to filter out creosote via condensation.
  2. Using sawdust instead of pellets in the AMNPS. Some people claim that you get better results by grinding up the pellets in a blender, but I find that hard to believe. Todd's sawdust works great and avoids possibly ruining a blender by grinding up hard pieces of wood (I melted my Cuisinart bowl last year trying to pulverize some small wood chips).
  3. Making sure that everything was at the same temperature before smoking (one of the key points of this thread).
Ambient air temperature, inside and outside my MES 30" Gen 1 was 60 degrees throughout the 2.5 hour smoke. I used hickory sawdust, but I think it would be better if I use Apple or Maple sawdust next time.
 

daveomak

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Mr. T helped me improve my cold smoking technique and today, by following his advice in this thread and elsewhere, I had my first successful cheese cold smoke. I think the things which made the biggest difference compared to my earlier failures were:
  1. Putting the AMNPS in an external "mailbox mod." I designed my own mailbox mod and created an external smoking enclosure which has far more surface area than the typical mailbox. This increases its ability to filter out creosote via condensation.
  2. Using sawdust instead of pellets in the AMNPS. Some people claim that you get better results by grinding up the pellets in a blender, but I find that hard to believe. Todd's sawdust works great and avoids possibly ruining a blender by grinding up hard pieces of wood (I melted my Cuisinart bowl last year trying to pulverize some small wood chips).
  3. Making sure that everything was at the same temperature before smoking (one of the key points of this thread).
Ambient air temperature, inside and outside my MES 30" Gen 1 was 60 degrees throughout the 2.5 hour smoke. I used hickory sawdust, but I think it would be better if I use Apple or Maple sawdust next time.
I tried grinding wood chips....   It don't work....  the chips get stuck on a blade and the friction heats up the blender from whipping around at 300 MPH...    pellets seem to break up easier and pulverize pretty good...   You do need a powerful blender OR just order dust from Todd...
 

driedstick

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I like the metal mesh in the pipe,,, I think I will have to try that 
 

johnmeyer

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Joined Nov 19, 2015
 
I like the metal mesh in the pipe,,, I think I will have to try that 
The jury is out as to whether that helps much. I think the idea is absolutely spot on (left hand patting self on back), but the material I have isn't quite right. They didn't get that dirty. I need something that looks a little like that chain mail scrubber you use for CI skillets. However, most grease filters used in kitchen fan hoods are just aluminum mesh, so I know I can find the material if I look around. I guess I could just buy a replacement mesh, cut it up into 3" circles, and then stack them.
 

mr t 59874

Master of the Pit
SMF Premier Member
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Joined Jun 9, 2011
 
The jury is out as to whether that helps much. I think the idea is absolutely spot on (left hand patting self on back), but the material I have isn't quite right. They didn't get that dirty. I need something that looks a little like that chain mail scrubber you use for CI skillets. However, most grease filters used in kitchen fan hoods are just aluminum mesh, so I know I can find the material if I look around. I guess I could just buy a replacement mesh, cut it up into 3" circles, and then stack them.
If you are limited on space, I can see where the mesh may help in collecting deposits, but would do little to cool the smoke. It may also affect the draft, which may need adjusting to compensate for the blockage in the pipe. All in all, give it a shot and let us know how it works. 

T
 

johnmeyer

Master of the Pit
1,685
432
Joined Nov 19, 2015
 
If you are limited on space, I can see where the mesh may help in collecting deposits, but would do little to cool the smoke. It may also affect the draft, which may need adjusting to compensate for the blockage in the pipe. All in all, give it a shot and let us know how it works. 
Actually, since it dramatically increases the surface area which contacts the smoke, if I can get the right material, I am hopeful that it will significantly increase the capture of the "bad stuff." As for cooling, as long as the mesh stays in contact with the exterior, since aluminum is such a fantastic thermal conductor, I am expecting that it will actually stay pretty close to ambient.

Finally, while I mentioned that it was 60 degrees both inside and outside my MES during the smoke, I didn't emphasize the importance of that statement. That importance can be summed up this way: the smoke generator added no measurable heat to the MES during an almost-three-hour smoke. If there was an increase, it was buried by the digitizing error of the thermometer (each reading can be off by +- 1 degree, and therefore you can have identical readings even when the two thermometers register a two-degree difference). The thermometer outside and the thermometer inside the MES never differed by more than two degrees, and many times registered the identical temp.

So, at least for my setup when burning sawdust, additional cooling is most definitely not needed, and the only remaining issue is whether I can "scrub" the smoke more cleanly by adding longer lengths of conduit. Since I was unable to see any deposits on the second of the two elbows that connect the popcorn can to the smoker, my conclusion is that the net improvement of adding massive lengths of conduit, at least in my setup, is unlikely to produce much of an improvement.

However, other smoke generator setups might necessitate a more convoluted setup.

So, for me, this relatively simple setup is working really well and, when using Todd's sawdust, seems to produce a very satisfactory result that is exactly what has been described by Mr. T in his various excellent posts and blogs.

 

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