Outdoor cooks can choose from a variety of fuels when firing up their grill or smoker. And yet, if aroma and flavor are of the essence, he or she has no choice but to use firewood.
Firewood gives off smoke with a pleasant smell and spicy taste like no other; unlike gas, pellets, and even charcoal, it can be said that firewood is as much a seasoning as it is a fuel.
Not all firewood is created equal. You should never cook over certain species of shrubs and trees because the smoke they give off can make you—and the family members, friends, and neighbors sitting at your table—sick.
Grill or smoke your meat over well-seasoned hardwoods, and never use softwoods. Softwoods, such as fir, pine and spruce, produce soot, give meat a bitter taste, and, in some cases, contain sap and terpenes that can make you sick.
Before you get cooking, get in the habit of inspecting the firewood you are about to use to avoid hiccups.
For similar reasons, never cook over wood (even if it is hardwood) that has been painted, treated, or stained in a way that casts doubt on its safety. When it comes to your health and the well-being of the people you love, the responsibility is yours to err on the side of caution.
What Wood Not to Use for Cooking
When selecting firewood for grilling and smoking meat, the golden rule is to use hardwoods and stay away from softwoods, other woods containing toxins, and, last but not least, freshly cut lumber.
Softwoods in General
Softwoods are trees bearing needles and cones. Botanists call them Gymnosperm, a term derived from a composite Greek word meaning “naked seed.”
These cones are not always what you expect them to be:
Some conifers, the pine tree being the most obvious example of them all, bear pine cones.
Others, like the English yew, have cones that resemble berries. But, as explained by the researchers at Pennsylvania State University, yew’s wood and its “berries” are highly toxic.
The one thing that all softwoods have in common, the folks from the American Conifer Society point out on its website, is that their seeds are naked; they are not protected by an ovary or a fruit.
That is the opposite of hardwoods, which are generally flower-bearing and fruit-bearing plants.
Why am I telling you all this, you all may be wondering?
Not because I want to awaken in you a sudden interest in botany, not at all. It is because, as a griller or smoker who uses firewood for fuel, you need to learn to recognize and to not cook over softwoods.
The problem with softwoods is that they are resinous. When burnt, that resin can outgas terpenes—the fragrant but toxic compounds responsible for the way that most plants smell—which land on your grilled steak or smoked brisket.
When they are inhaled or eaten, terpenes can cause serious health issues for those are sensitive to chemicals or for those with respiratory illnesses.
It is as simple as that, fellers. So here comes my rule of thumb:
If a tree bears needles or cones, don’t use its timber for cooking. Examples of softwoods are, in alphabetical order, cedar, hemlocks, fir, juniper, larch, pine, spruce, all species in the redwoods family, and yew.
Add this post to your browser bookmarks and come back to it whenever you need a refresher. But remember that this list, while extensive, is not exhaustive. When in doubt, reach for your phone and Google whether a particular tree species is a softwood or a hardwood. I know that’s what I do.
Woods Containing Toxins
Hardwoods are generally safe to cook over. However, certain species of hardwoods have no place anywhere near your grill’s coal grates or your smoker’s firebox.
“A number of trees and shrubs contain toxins that are harmful to humans and should not be used for smoking,” the great state of Sconnie Nation’s Wisconsin Firewood say on their website.
The toxins can survive the burning process and end up in your meat, making you sick.— David Haug of Wisconsin Firewood Co.
Clearly, that is not something you want to happen at your cookout. The family-owned firewood company points out that these plants include mangrove, poisonous walnut, sassafras, oleander, yew, tambootie, and laburnum (a.k.a. Golden Chain tree).
For your safety and the safety of those eating your food, do not cook over these firewoods.
Freshly-Cut or Poorly-Seasoned Firewood
It is said that you should choose your firewood as you choose your spices.
If you concur with me on this, your spices should be well-dried, so that their essential oils are preserved and their aroma and flavor are enhanced—and your firewood should be well seasoned so that it burns better, and smolders with a sweeter, milder smoke.
This can be difficult to achieve if you are cooking over freshly-cut firewood, also known as “green wood.”
Green wood contains too much moisture compared to firewood that’s been seasoned or dried in a kiln. As a result, it gives off a dirty and heavy smoke that makes your food taste bitter and causes soot to build up in your chimney.
The same applies to wood that hasn’t been dried properly. As Will Fleischman writes in his 2016 cookbook, Smoking Meat: Perfect the Art of Cooking with Smoke, if the wood isn’t cracked on both ends and feels disproportionately heavy for its size, it’s probably too moist.
If you are curious about the details, head on over to “Can You Smoke Meat With Freshly-Cut Wood?”
If it has needles or bears a cone, the safe thing to do is leave it alone.
When you are considering to grill or smoke meat over a new kind of wood, always double-check on the Internet whether or not it’s fit for cooking in the first place.
And, not to be underestimated, dry your firewood. In case that isn’t an option, find a local supplier of seasoned or kiln-dried wood who won’t cheat you on quantity and will consistently provide you with high-quality fuel.