Extractives

You may have noticed that most of my utensils and cutting boards are made from just one type of wood and that many dark wood tones are absent. This is due to the presence of extractives—non-structural components that serve as natural defenses against fungi and animals. Extractives are more prevalent in heartwood, the darker center of a tree, compared to sapwood, the lighter outer wood (as pictured above). This higher extractive content is what gives heartwood its darker color.

If you're a woodworker familiar with exotic or tropical woods like purpleheart, padauk, and bloodwood, you may have experienced mild to severe irritations and reactions when working with them. These reactions are due to the high levels of extractives, which can be quite toxic. In the kitchen, water is the primary means by which extractives are transported, making it crucial to use woods with low extractive counts for cutting boards and cooking utensils. The defense mechanisms of trees include not only darkening the wood but also affecting its smell. Woods like sandalwood, camphor, and cedar have strong aromas due to their aromatic extractives. 

Ironically, teak, which has a high extractive count, is often used for cooking utensils. To manage these extractives, teak utensils are always coated with a nonpermeable finish to create a barrier between the wood and boiling water. We'll explore why it's not advisable to finish wood products regularly exposed to high temperatures and moisture, and the effects of prolonged moisture if not properly dried. Choosing the right wood is the crucial first step in making safe, effective kitchenware.