What You Need To Know About Wood, Smoke, And Combustion

The different types of wood Logs. Cut from hardwoods, fruitwoods, and nutwoods, but never pine and softwoods that have a lot of turpines and sap. These woods must be dried. At right is a small part of the acre sized pile of post oak at Kreuz Market in Lockhart. TX. Below is a "burn box" for preparing hardwood embers for barbecue at a different restaurant. Logs are dropped in the top of the 55 gallon drum, they rest on rebar that has been inserted near the bottom. The glowing embers are removed from a door cut in the side and shoveled into the pit. Chunks. Wood chunks from golf ball to fist size are fairly easy to find in hardware stores. Chunks burn slowly, and often a chunk or two about the size of an egg weighing 2-4 ounces is all that is necessary for a load of food. Because they are slow, steady sources of smoke, they are in many ways, the most desirable. When you use chunks, you can add one or two at the start of the cooking cycle and you don't need to keep opening the unit and mess with the equilibrium in the cooking chambers atmosphere. Chips. About the size of coins, chips are also common and easy to find. They burn quickly and you may find that you need to add them more than once during the cooking cycle. Chips are fine for short cooks, but for long cooks, chunks are better. Pellets. Pellets are made by compressing wet sawdust and extruding it in long pencil thick rods. They are broken into small bits about 1/2" long. Food grade pellets contain no binders, glue or adhesives, and when they get wet they revert to sawdust immediately. The machines must be lubed with food oils. Pellets were originally developed for household heaters. These pellets should not be used for cooking because they might have pine and binders, and the machines are lubed with petroleum. Some cookers use pellets as the main fuel, for both flavor and heat and pellet cookers do very very well in competition. Because they can be fed into the fire in a very controlled manner, usually by an auger, pellet cookers can be regulated with a thermostat, making them very controllable. Food grade pellets can be a good concentrated source of smoke flavor on grills and smokers, and a handful or two is usually all that is necessary for ribs or fowl. Pellets used as fuel to fire pellet grills are mostly oak, a stable burning wood. If they say they are hickory, they are usually less than half hickory, a fact that does not always appear on the label. They usually come in 10-40 pound bags. BBQr's Delight makes 12 flavors of pellets in small 1/10 pound or 1 pound bags that are 100% flavor wood including alder, apple, cherry, hickory, orange, pecan, and others. Their Jack Daniel's pellets are a mix of oak and charcoal from oak whiskey barrels, and their Savory Herb is oak with herbs in the blend. I love using these products because they are easy to measure and control. They only burn for about 20 minutes at 225°F, so you must get your meat on before the wood. There's a pretty good forum for people who have pellet cookers at Pelletheads.com. Pellet chunks. Another form of pellet is the pellet chunk or brick, the most notable being made by Mojo-Bricks (right). These are wood chips and sawdust from the mills compressed until they bind. They come in a variety of flavors. I have had very good luck with them on a cariety of smokers. Bisquettes. Bisquettes are another variation on the compressed sawdust idea made for the Bradley Smoker. They look like small brown hockey pucks. Sawdust. Sawdust can also be used for flavor, but it burns quickly and is rarely used. There are even a few small smokers, like the Camerons, that use smoldering sawdust.

For gas grills Getting smoke on gas grills is sometimes tricky. You need to experiment when you are not cooking food. Here are some things to try. Use chunks, not chips. Wood chunks are best for gas grills because chips and pellets often fall through. But sometimes they just won't smolder. A reader, Nei Ng, found a solution: "The first thing to do is to wrap the wood in foil like the wood chip pouches. Make a small pile of charcoal on the flavor bars [or heat dispersers]. [They will ignite, but] the pile isn't hot enough to really change the overall temperature, and the wood should be lit by the time the grill has reached 225°F. Place the wood chunks wrapped in foil over the hot charcoal and they should start smoking within a few minutes." The foil pouch for chips. Put your wood chips in a foil pouch or make a smoke bomb (above). For a pouch, use heavy duty foil or two or three layers or regular foil. Poke holes in the top so the smoke can escape. Place the pouch as close to the heat as possible. Reader Jeff Hale has this tip: "Make up a bunch of pouches in advance. When one is burnt up... throw another one on." You will know when to add a new pouch when the smoke stops. Another option is to use a small aluminum pan with holes poked in the bottom. If you are having problems getting the wood in a pouch to smoke, before you put the meat on, turn the burner on high, put the foil packet on and wait for the chips to begin smoking. Then dial the burner down so you can get the oven to 225°F. Or try Nei Ng's technique of using charcoal (above). If the wood burns. It is possible that your wood might just catch on fire and not smoulder. If it doesn't, you need to be creative. Try moving the wood so it is not in direct contact with the flame. Try putting the wood in a small cast-iron frying pan or a flattened steel can. Finally, you could soak the chips for a few hours, although the water will evaporate quickly and you likely will have the same prob once the water evaporates. Be creative! Outsmart the flame! Smoking indoors If you have a good exhaust system this method works well. If you have a wimpy fan, don't even think about it. Get a stainless roasting pan, cover the bottom with heavy duty foil. Sprinkle sawdust on top or the Chinese tea mix (at right). The best source of sawdust is to take a handful of wood pellets, get them wet, and either let them air dry or pan dry them on a low temp. Once the sawdust or tea is done, lay a layer of foil over them, but not all the way to the edge. This keeps drippings from extinguishing the smoldering wood. Place a rack like a pie cooling rack above the second layer of foil, them the food goes on the rack, and then cover the whole shootin' match. You can make a cover several ways. Lay a second, identical roasting pan upside down on top, and clamp it down with metal or wooden clothes pins. Lay a sheet pan on top of the roasting pan and weight it down with a sauce pan or a brick. If the food is tall, you can fashion a lid from foil, just crimp it tight around the edges. Foil is a good method if you need to insert a food thermometer. Preheat the oven to at least 350°F and crank up the exhaust.

Meathead's smoke bombs This method is ideal for both gas and charcoal cookers when you have a long cook and getting under the grate will be tricky, like when there's a full packer brisket on board. Get two disposable aluminum loaf pans. Add dry wood to both. Pour enough water in one to cover the wood. The dry pan will start to smoke quickly. About 15 minutes after it is all consumed, the other pan will have dried out and begun smoking. Getting the correct amounts of wood and water may take you a few cooks to perfect, but you will figure it out. I can tell that much about you.

Cedar planking I asked my friend Ron Shewchuk why nobody burns cedar for smoking. He's the author of Planking Secrets: How to Grill with Wooden Planks for Unbeatable Barbecue Flavor. Via email he said "It's funny, Meathead, I would never use cedar chunks or chips in my grill or smoker, and yet I cook food on cedar planks all the time. Plank cooking is just another way of getting wood smoke flavor into a piece of meat. You soak an untreated western red cedar plank in water for a while, then the plank on your grill, let it heat until it starts to crackle, and then put your salmon or whatever on the plank. It steams and smokes. "But cedar's astringent vapors don't go well with everything. They're great with pretty much all seafood, especially salmon, and they're amazing with tree fruits like peaches, pears and grapefruits. They also add an interesting edge to brie and pork, even leg of lamb and prime rib of beef take on new meaning when cooked on a cedar plank, but it's not for everyone. I personally find that cedar doesn't go as well with chicken, but I can claim to have successfully cooked almost everything that one would grill on a cedar plank, including tomatoes, stuffed potatoes, bananas and even pear crisp! "Still, if I am smoking a side of salmon I choose alder or hickory."

Chinese tea smoking For centuries the Chinese have been preserving foods and adding flavor with tea smoke. In fine Chinese restaurants tea-smoked duck is a popular delicacy. The flavor is distinctive and significantly different than smoking with wood. Experimenting with this Chinese technique can really add spark to duck, chicken, fish, pork, and even beef. Here's how: We begin by making an aluminum foil pouch, then stuff it with tea and other aromatics, poke holes in it, and place the pouch on the coals or on the gas burner of your grill. You can riff on the contents of the pouch, but here's the basic recipe: Ingredients 1/4 cup tea leaves 1/4 cup brown sugar 1/4 cup rice zest of 1/2 orange 10 whole star anise pods 2 (3" long) cinnamon sticks About the tea. You can use any tea you like, and I usually use whatever is the oldes tea I have instock. Aromatic teas are best. About the sugar. The sugar burns and smokes and creates a burnt marshmallow scent. About the rice. Don't leave this out. It smolders and helps maintain the burn. You can use aromatic rice like jasmine rice. About the orange zest. You don't have to use a zester, a vegetable peeler will work. Just scrape off the orange skin and try to exclude the white pith. Orange skin is filled with aromatic oils that are important to the scent. You can try other citrus such as lemon, lime, or grapefruit. About the aromatics. This basic recipe uses star anise and cinnamon. You can play with others such as cumin seed, mustard seed, herbs, galanga, dried ginger, peppercorns, or cloves.

Smoking with herbs We have a nice herb garden and at the end of the season there are always a few unpicked oregano, basil, and other herb bushes. I cut the above the roots, and stick them in paper bags to dry. Then I crumble them, and I throw them on the grill after the meat is on. They burn fast, put out a lot of smoke that smells like you are doing something illegal, and add an exotic aroma to the food. I use them mostly on seafood, which cooks quickly and doesn't have time to absorb slowly smoldering hardwood.

"When a lovely flame dies, Smoke gets in your eyes." Song by Jerome Kern and Otto Harbach, performed by the aptly named The Platters

By Meathead

Originally all barbecue and grilling was done with logs of dried hardwood as the fuel source. Old timers would stack the logs, light 'em up, and let them burn down to glowing embers before shoveling them into a pit under the meat.

Heat cooked the meat, and smoke from the wood and the dripping juices landed on the meat imparting a distinctive seductive scent that is the essence of grilling and barbecue. But it is difficult to control the heat and flavor when cooking with logs, so today, only a few expert pitmasters cook with logs only.

Today, most barbecues use charcoal, gas, or electricity to produce the heat, and they get flavor and aroma from the addition of measured amounts of hardwood in the form of chips, chunks, bisquettes, pellets, logs, or sawdust. Click here for a good buying guide to smokers.

Wood also plays a role in the color of the meat and the formation of the crust on the meat, also called the bark.

Hardwoods, which include fruit and nut woods, have compact cell structures. Softwoods, like pine, fir, spruce, redwood, hemlock, and cypress are all evergreens (coniferous trees), and they have more air, more pungent sap, and burn fast. They are not recommended for cooking. We'll talk more about wood choices below.

Combustion gases

Logs, charcoal, propane, liquid natural gas (LNG), pellet, and electric cookers each produce tastably different flavors because each fuel produces a unique combination of combustion byproducts.

Electric cookers use a hot coil for heat, so there is no combustion and thus no combustion gases. Even if you put wood chips on an electric coil, the flavor is vastly different, and to most tastes, inferior because the food lacks the complexity that combustion gases from the other fuels produce. The secret to good flavor is the right combustion gases and smoke from wood.

Below are two slabs of ribs. The one on the left was cooked on a charcoal smoker. The one on right on a gas smoker. You can even see the difference.

What is combustion?

Wood and pellets. Fresh cut hardwood has a lot of water in it, up to 50% by weight, it produces a lot of steam and off flavors during combustion, and it takes up to 45% more energy (charcoal or gas) to dry it out, so most wood for cooking is hardwood that has been air dried. Dried hardwood is rarely totally dry, perhaps 5% water. Of the remaining 95%, about 42% is cellulose, about 38% hemicelluloses, 19% lignin, and 1% minerals 1%. Actual numbers can vary depending on the wood species, subspecies, age, soil, climate, and vintage.

Cellulose is a long chain molecule called a polysaccharide, a carbohydrate. Hemicelluloses are different carbohydrates and sugars. Lignin is another complex polymer in the cell walls that gives the wood strength.

The main minerals in wood include oxygen, hydrogen, nitrogen, potassium, and carbon. There can also be trace amounts of sulfur, sodium, chlorine, and heavy metals. These minerals can significantly impact the aroma and smoke flavor.

Hardwoods have more minerals than softwoods, but their quantity is significantly influenced by where they are grown and in what soil, probably more than the species according to The Forest Encyclopedia. This is very important to note, especially when you are caught up in the game of deciding which wood to use for flavor. Climate and soil have a stronger influence than the type of wood.

Wood combustion, technically called pyrolysis, starts to take place in the 500 to 600°F range and requires significant amounts of oxygen. Let's call the combustion point 575°F on average for the sake of discussion. At that temp the wood has absorbed a lot of heat and the water has been driven off as vapor. It is ready to burn.

Charcoal. Charcoal is almost pure carbon made from wood that has been preburned. The process is centuries old. When burned charcoal produces heat, carbon dioxide, carbon monoxide, water, and other gases. It burns hotter and cleaner than wood. For a detailed explanation of how it is made and how it works, read my article on the Zen of Charcoal.

Propane and liquid natural gas. When propane and oxygen are ignited, they produce heat, water vapor, carbon dioxide, carbon monoxide.

What is flame

Primary combustion is the pyrolosis of the wood or charcoal, and secondary combustion is the pyrolosis of the gases emitted at high temps. It is the combustion of gases that produces flames. This pyrolysis of gases also produces most of the heat.

In primary pyrolysis, heat creates gases that rise from the fuel creating something like a gaseous bubble. The gas bubble is surrounded by air which contains about 21% oxygen. If there is enough energy the gas ignites and starts the process of combining its molecules with the oxygen. Where the gas and air meet, and if all the gas is able to combine with the oxygen, a blue flame is visible. If the gases don't burn completely, the flame glows yellow or orange. If unburned gases escape the bubble cools and turns into smoke. Meanwhile, the energy from the combustion causes more gas to evaporate.

When there is too much oxygen, the flame is yellow and orange. A gas grill has a venturi, a valve that blends the gas and oxygen like a carburetor. When properly blended the flame is mostly blue. Gas grills are typically tuned for the proper air/gas mix at the factory, but occasionally they are not and occasionally they need adjustment over time. Venturis usually have a set screw. Do it at night so you can see the color of your flame best.

What is smoke?

When burned thoroughly in a lab, and wood is never burned thoroughly in a grill or smoker, it produces about 8,600 BTUs per pound of heat, about half of the mass is converted to carbon dioxide, and about half to water vapor. If the wood does not get enough oxygen it can still undergo primary combustion, but not secondary. It will not burst into flame, it will smolder, and smoldering wood produces lots of smoke and a different flavor than burning wood. That's why ribs smoked by a fire made from logs tastes different than ribs smoked by a fire made from charcoal, gas, or electricity.

Smoke includes as many as 100 compounds in the form of microscopic solids including char, creosote, ash, as well as combustion gases that include carbon monoxide, carbon dioxide, nitrogen oxides, polymers, and liquids such as water vapor, and phenols. When they contact food they can stick to the surface and flavor it. Most of the flavor comes from the gases, not the smoke particles, according to the AmazingRibs.com science advisor, Dr. Greg Blonder, and the composition of the gases depends on the amount of oxygen and the termperature.

How much of each compound is in the smoke depends primarily on the composition of the wood, the temperature of combustion, and the amount of oxygen available.

Smoke from wood or charcoal for cooking can range from bluish, to white, to gray, to yellow, brown, and even black. Blonder explains that "Pale blue smoke particles are the smallest, under a micron in size, and about the size of the wavelength of light. Through a mechanism called the Tyndall Effect, red light passes through this halo of small particles, while blue light is scattered sideways to our eyes. On the other hand, pure white smoke consists of larger particles, a few microns in size, and they scatter all wavelengths in all directions. Gray smoke contains particles large enough to actually absorb some of the light and colors." Among experienced cooks, the most desirable smoke is blue as seem coming from the smoker on the right in the photo below.

Creosote

Creosote is among the compounds in smoke and it is the Jekyll and Hyde of smoke cooking.

On the Dr. Jekyll side, creosote contributes positively to the flavor and color of smoked foods and acts as a preservative, among the reasons that smoking meat was used for preservation before refrigeration.

Blonder says "Creosote is always present in charcoal or wood smoke, and a few components of creosote (guaiacol, syringol, and phenols) are the largest contributors to smoke flavor. No creosote, and the meat might as well have been boiled."

On the Mr. Hyde side, "If the balance of the hundreds of chemicals in creosote shifts, it can taste bitter rather than smoky."

What is creosote and where does it come from, and why is it two faced?

Commercial creosote is produced by distilling tars from primarily beechwood or bituminous coal (not charcoal). Careful control of the combustion temperature, oxygen flow, and pressure produce a wide range of aromatic oils and tars. Creosote from coal tar is the black stuff used to preserve telephone poles and railroad ties. Coal tar creosote is classified as a possible carcinogen. Anybody who has a wood burning fireplace knows that creosote from logs can cling to chimneys, clog them, and even ignite, burning down the house.

These industrial chemicals give the creosote found in barbecue smoke a bad name. I am unable to find any research that implicates the small amounts of creosote in barbecue with a health risks.

But you can see creosote deposited as a sticky brown tar on the inside of a smoker, especially if it has a stainless or aluminum interior. Many cooks consider this "seasoning" and find it desirable. It is not. The best cooks powerwash the interior of their cookers regularly. It is not likely to combust, but it can vaporize or drip on the food. For more, read my article on grill and smoker cleaning and maintenance.

According to Blonder, "When you smoke low and slow at temperatures like 225F, many smokers require you to control the fire by damping the oxygen supply which moves it below the ideal combustion zone, creating black smoke, soot, and more creosote. The best smoke cookers combust at a high temp in a separate chamber to create the ideal flavor profile, then direct a small fraction of the smoke across the meat.

"To control creosote, I suggest using less charcoal so you can burn it hot and more efficiently, but the smaller number of embers will provide less heat. You will have to replenish the coals more often, but the food will taste better and there will be less creosote. Avoid resinous woods such as pine and cedar.

"Humidity can affect creosote production and its flavor profile because moisture in smoke can scavenge some of the creosote compounds selectively and then it can condense on cool meat and cool smoker walls, especially in winter. All this means there is plenty of room for barbecue skill and experience."

Here are other ways to avoid creosote formation: (2) Don't add a lot of cold meat to the smoker at once; (3) If you are using charcoal or logs, use a small hot fire that does not have to be stifled by closing dampers to keep the heat down; (4) Cook in warm weather; (5) Preheat the smoker and give the walls time to warm up; (6) Don't add a lot of cold charcoal, start it up first in a chimney; (7) If you are cooking with wood, preheat the logs by letting them sit on the firebox or in the cooking chamber; (8) Leave the chimney open at all times; (9) If the fire gets too hot, don't close the dampers, open the firebox door to let out some of the heat; (10) Check the cooking chamber temperature at least every 30 minutes; (11) Practice, practice, practice.

Smoke and food

In a smoker or grill, after combustion, the smoke rises and flows from the burn area into the cooking area. Some of it comes in contact with the food, but most goes right up the chimney and very little contacts the food.

"Curiously, around every object is a stagnant halo of air called the boundary layer. When cooking, a viscous layer of air builds up around the food. Depending on airflow, surface roughness, and so on, the stagnant layer of air around a piece of meat might be a millimeter or two in thickness. When smoke particles approach the meat’s surface, they follow that boundary layer around the food. Very few ever touch down. We've all cursed a form of this piece of physics while driving: Gnats follow the airstream over the windshields, while larger insects leave green sticky splats at the point of impact."

To see the way smoke is absorbed by food, Blonder did some experiments. He began by suspending two cotton disks in a MAK 1 Star pellet smoker at 230°F for an hour. Pellet smokers are very efficient and produce very fine particles. In fact some owners complain that they don't impart enough smoke flavor.

One disk was dry, one soaked in water. The results, below, are pretty dramatic. Smoke adhered to the wet surface far more than the dry surface. Remember, the atmosphere inside a pellet smoker is as dense as a London fog, yet no smoke got stuck in the fine cotton pad.

He then suspended three disks in an electric smoker for 30 minutes. This time he added a disk soaked in cooking oil. It attracted more smoke than the dry disk, but not as much as the wet disk.

Why does the wet pad gather so much more smoke? Blonder explains that smoke impacting the dry pad simply bounce off because there is nothing to hold them. But the oily and wet pads are tackier.

But why does the wet pad attract more smoke than the oily pad? The answer is thermophoresis, according to the physicist.

Thermophoresis is a force that moves particles from a warm to a cold surface. He showed this by placing two smooth, dry, glazed tiles in the pellet smoker. The left tile is a control. It did not go in the smoker and is shown here just so we can see what it looks like before smoking. The middle tile was warmed to 225°F before being placed in the smoker, and the right hand tile was chilled to 29°F.

In the first experiment, the wet cotton pad was cooled by the evaporation of the moisture in the pad so it was well below the temp of the others. That's why it was smokier.

The same thing happens to meat when you put it in the smoker. If it is cold and wet it will hold more smoke. As it warms and dries out, less smoke is absorbed.

Smoke flavor is almost all on the surface of the food

As we see, smoke particles glom onto the surface of foods. There they may dissolve and penetrate a bit below the surface but not very far. Rarely more than 1/8". This is the same phenomenon with marinades and brines. Meats, especially, are hard to penetrate. Don't believe me? Here's how to prove it to yourself. Get a nice thick piece of meat, at least 1" thick, like a cross section of pork loin or a brisket or pot roast. Smoke the heck out of it at 225°F until it is 190°F to 200°F internal temp. Let it cool a bit and taste it. Yummmmmm! Smoky! Now cut off the surface and edges in 1/8" thick slices. Make sure the center meat doesn't get to roll around on the cutting board in the juices from the surface. Now taste the center. No smoke!

Enough is enough

One of the biggest mistakes we frequently make is using too much smoke. Too much smoke can make your meat bitter or taste like an ash tray. Smoke is like salt. You can always add more but you can't take it out. Do not try to cook with wood. It is too hard to control the temp and the amount of smoke. When you become an expert, you may be able to cook with wood only, but at the outset stick to charcoal, propane, or electricity. I cannot give you a precise amount because each cooker is different and the amount of wood to get the right flavor will depend on the volume of the cooking chamber, the airflow, leaks, how often you peak, the kind of wood you use, and of course, your preferences. You will need to experiment, but a good rule of thumb is start experimenting with about two ounces of wood, regardless of the cut or weight. For dense, thick cuts of meat such as pork butts for pulled pork or beef brisket, you can double or triple the amount of smoke. If the results are not smoky enough, you can add more wood on your next cook.

 

Putting wood to work

So here's how to take advantage of this info.

Don't soak the wood. It does no good. Water can't penetrate it. That's why they make boats from wood. Read my article on soaking wood and look at the photos for proof.

Size matters. For long cooks, chunks of wood from golf ball to baseball size work best. They burn more cooly, smolder and last longer, while chips and pellets tend to combust and disappear more quickly. For short cooks, like a steak, chicken, or fish, small chips and especially pellets work best because they produce more smoke in a short burst.

What to do if the wood catches on fire. You want the wood to smolder, which is the point just before ignition when it produces smoke but hasn't yet burst into flame. The difference is oxygen. So if your wood bursts into flames, next time wrap it in foil and poke a few holes in the foil to limit the oxygen supply.

Make sure coals have plenty of oxygen. If coals are choking for lack of oxygen, they burn incompletely and can coat your food with gray soot. If that happens, get the meat off, rinse it, adjust the fire and put it back on.

For charcoal grills. Put dry wood right on the coals or in foil packets and close the lid to keep it from bursting into flame.

Go easy on the wood. Wood giveth and taketh. You can ruin a batch of meat pretty durn easily by oversmoking. Oversmoked meat can be inedible. Tastes like an ashtray. Oversmoking is the most common error of the beginner. So start with only a little wood and as you get the hang of your cooker and your tastes, you can gradually add more each time you cook.

Preheat your smoker, add the wood, and get the smoke flowing before adding the meat. Go for blue or white smoke. Learn your tool. Practice without meat. Do dry runs. Calibrate.

Use cold meat. Do not let the meat come to room temp.

Use a spice rub. Rough up the surface with a spice rub, a layer of spices and herbs to reduce the boundary layer.

Keep the meat moist. Use water pans in your smoker. They add water to the atmosphere, but more importantly the water condenses on the meat's surface. You can also do this manually by spritzing the meat with a spray bottle you can buy in a drug store. A mop or basting brush will just wash off your spice rub. You can use apple juice if you wish, but it adds very little to the flavor in comparison to the rub and sauce. You can use cranberry or pomegranate for color. But really, all you need is water. And don't worry, opening the cooker every 30 minutes to spritz will not slow the cooking process measurably. This is another myth Blonder has debunked. Click the link.

Add humidity to the atmosphere with a water pan in the smoker. And don't bother putting juice or beer in there.

Which wood? Cured (dried) hardwoods with low sap are the best for barbecue, especially fruit and nut woods such as apple, cherry, peach, grape, hickory, alder, mesquite, maple, and oak. When dry they produce the best smoke. They all have slightly different flavors, and it is almost impossible to describe them. I avoid mesquite. It can be harsh, bitter, and pungent. Hickory is the tried and true mate for pork, but some people find it too aggressive and occasionally it can taste bitter. Fruit woods tend to impart a sweetness.

To make things complicated, there are different kinds of each wood. For example, there's shagbark hickory, scrub hickory, pignut hickory, and red hickory. The climate the tree is grown in can impact flavor. Florida hickory tastes different than Michigan hickory. Furthermore, the amount of bark and can significantly impact flavor, far more than the type of tree you pick. How long it has dried and the percent water left in the wood impacts flavor and aroma.

To make matters worse, there is no guarantee that the wood in the bag is the wood on the label. Coffee, olive oil, and fish markets are regularly rocked by scandals of fraudulent labeling. Is it a stretch to wonder if a wood chopper in Arkansas throws oak in bags to fill a large order for hickory from a hardware chain when he runs out of the read deal? Do athletes take steroids? There is no government inspector checking wood suppliers...

The internet is full of guides attempting to describe the flavors of different woods. They remind me of the floral descriptions wine lovers use. I don't find these wood descriptions very accurate. Here's the best I can do based on the woods I have used. And remember, I have won wine tasting championships, and I would love nothing more than to tell you that a particular wood has "nuances of spice with an undertone of earthiness". I just can't do it.

• Mild (best for foods that are not heavily seasoned or sauced). Alder, apple, cherry, grape, maple, mulberry, orange, and peach.
• Strong (best for strong flavored foods with lots of spice and/or sauce). Hickory, mesquite, oak, pecan, walnut, and whiskey barrel.

Then there are the exotic woods that I haven't tried yet: Citrus, dried citrus peels, pistaccio wood, corn cobs, nut shells, coconut shells, mango, and even mahogany.

Bottom line: Stop obsessing over which wood to use. Pick on and stick with it for a whiole. The quality of the meat, the spice rub, the cooking temp, the meat temp, and the sauce impact the final taste profile far more than the name on a bag of wood. Once you have everything else under control, then you can try different woods.

Bad wood. Whatever you do, never use wood from conifers such as pine, fir, cyprus, spruce, redwood, or cedar. They contain too much sap and they can make the meat taste funny. Some have been known to make people sick. Yes, I know that cedar planks are popular for cooking salmon on, but I don't know anyone who burns cedar as a smoke wood. I have also heard that elm, eucalyptus, sassafras, sycamore, and liquid amber trees impart a bad flavor.

Never use lumber scraps. Some lumber is treated with chemicals that are poisonous. Never use wood that has been painted. If you have branches fall from trees, make sure they are not moldy. By the way, that's why I don't use lump charcoal. You can see lumber scraps in there and it makes me wonder how careful they are to prevent treated lumber from getting in there.

Never use wood that is moldy.

Use dried wood. Green woods have more sap, burn irregularly, and impart different flavors than dried wood.

Bark or no bark? Some wood has more bark than others and that can impact the flavor. Some folks say you should remove the bark. I don't bother, but there may be something to this.

Make the wood smolder. You don't want the wood to catch on fire and go through rapid combustion. You want the wood to smolder. The way to do this is to starve it by limiting oxygen. If your wood is constantly breaking into flames, wrap it losely in foil and poke holes in the foil.

What does Meathead prefer? If I was on a dessert island I would want a bag of apple chunks and a bag of small apple chips or pellets. I would use the chunks for steady slow release smoke, and the chips or pellets for quick smoke.

Add wood early. Meat soaks up more wood flavor at the start of the cook, and the colder the meat the more smoke it absorbs.

Where to get it? There are a number of barbecue specialty stores opening around the country and there may be one near you. Most hardware stores carry only hickory or mesquite, but a few carry expanded barbecue supplies and a selection of woods. Watch the newspaper for ads from stores promoting a lot of grills. Then give them a call. Also there are a number of places to buy wood on the net. Another option is to go to an orchard and ask if you can have some dead limbs.

How much is enough? It is best to weigh the amount of wood you use so you can increase or decrease it as you wish in future cooks. The amount you need will vary depending on your preferences, how tight your cooker is, they type of fuel, the thickness of the meat, and if you use chunks, chips, or pellets. Pellets are especially good for measured amounts.

Here's where to start your experiments: On charcoal, use no more than 8 ounces by weight of wood for ribs. Use no more than 16 ounces for pulled pork and brisket, and no more than 4 ounces for turkey and chicken. Add it in doses. Put on about two ounces when you put on the meat and add another two ounces when you can no longer see smoke. On gas grills, double the amount.

Take notes. Measure the wood and write it down so you can add more or less the next time you cook. Use less than you think you need. Keep records of your experiments on a cooking log.

Click here to see the original unedited data from Blonder's experiments.

This page was revised 1/7/2013