By Dylan Clay
When smoking food you want to achieve “thin blue smoke.” This color of smoke implies that the burning of the wood is efficient.
In this state, the chemical compounds that comprise the wood break-down into combustible gases – these gases result in desirable aromas and taste sensations that can attach themselves to your food.
Where-as “Thick white smoke” is essentially inefficient combustion and results in acids and gases that aren’t palatable; Namely wood creosote which is bitter.
Smoke from wood or charcoal can appear white, gray, blue, yellow, brown, and even black. However, not all smoke is considered “good” smoke.
Smoking meat is almost sort of a misnomer as you’re not after white/black clouds of billowing smoke.
Rather the “good smoke” is blue – bordering on translucent.
Hardwoods used for smoking meat are primarily made up of three organic compounds:
The cellulose and hemicellulose make up the structural material of the wood, where-as lignin holds them together.
Cellulose and hemicellulose are chains of glucose (sugar). When burned they effectively caramelize and produce carbonyls; These compounds are responsible for most of the color components as well as the sweet, flowery, and fruity aromas.
The breakdown of Lignin creates phenolics (aromatic compounds) that create distinct elements like smokiness and spiciness, as well as pungent compounds like syringol and guaiacol.
This is the reason why Mesquite wood has a pungent smokey flavor. It has far more lingin content than say hickory.
All of these concepts are important to understand as they are directly related to thin blue smoke.
Thin blue smoke is essentially a thermochemical process called pyrolysis.
Pyrolysis is the decomposition of volatile materials (in this case hardwood) in a low/no oxygen environment featuring high heat.
Since there are low levels of oxygen present, the material doesn’t combust, however the chemical compounds that comprise the wood (cellulose, hemicellulose, and lignin) are allowed to decompose into combustible gases and charcoal.
Thin blue smoke is the result of a equilibrium (fuel, oxygen, heat) being achieved and the burning process being deemed efficient.
In this state the fuel in the woods carbonize or caramelize which results in thin blue smoke.
Note: Pyrolysis is the process used to create lump charcoal.
This section is based on personal experience and what I’ve found after smoking meat for roughly a decade.
Keep in mind, barbecue is a centered experience and what I like, you may not.
The reason thick white smoke is considered “bad” or “dirty” is because it implies incomplete combustion (gas particles that are left unburned).
Prolonged exposure results in an acrid taste from ash and creosote. Thick white smoke’s particles are also much larger and will readily adhere to wet surfaces (meat).
Smoke is comprised of as many as a hundred compounds.
These compounds manifest themselves as solids like:
As well as gases like:
As well as liquids like:
There are three things necessary to produce smoke:
When all of these elements are introduced, combustion occurs; This is how the “fire triangle” works.
In order for smoke to be produced the heat and oxygen can be adjusted so that the combustible material will smolder rather than burning resulting in visible smoke.
Remember, most of the flavor components come from the gases, not the smoke.
The composition of the gases depend on oxygen and temperature.
As described above, we know hardwoods are comprised of cellulose, hemicellulose, and lignin. These components burn simultaneously and the compounds associated with them interact throughout the combustion process.
The following temperatures and observations are from Dr. Greg Blonder’s research on this topic:
While no fire is uniform, it’s best to fall within that sweet spot of 650F-750F.
We can see from the above that lower temperature smoke (450F) creates an acrid bitter taste. High temperature smoke also destroys the desirables; Meaning the sweet spot is 650-750F.
This is the biggest reason some people opt to smoke hot and fast (275+) as apposed to low and slow (225).
On many smokers, smoking at 225 requires you to dampen the oxygen which starves the fire and results in incomplete combustion and the non-desirables, namely wood creosote.
Virtually all wood will emit white/grey smoke during the initial phases of combustion as moisture is being released.
If you’re using a water pan, the water releases steam that you may confuse for white smoke – as it appears whitish.
Wood is hygroscopic meaning it will lose/gain moisture depending on the humidity and ambient temperature. Seasoned hardwoods used for smoking typically have a 15-20% moisture content.
After 20 minutes, if your smoker still has billowing clouds of white smoke, you likely have a problem with the wood being used or the airflow/oxygen level – prolonged exposure will likely result in a more acrid or bitter flavor.
The keyword being prolonged.
In my experience, if you’re cooking hot and fast (300+), white smoke works perfectly fine for burgers, steak, chicken, even ribs. However, smoking with white smoke for 10+ hours is going to create acrid/bitter flavors.
This also means for shorter smokes – the color of the smoke doesn’t matter as much, if at all. So if you’re smoking ribs, chicken, turkey breast, fish, etc. You don’t have to worry about the color of the smoke.
A lot of beginners are told to wait until the white smoke subsides, however, this isn’t necessary. You can feel free to put the meat on the grates, add your wood chips or chunks and wait for the smoke.
