Grenadilla vs Cocobolo vs Mopane: A primer

For most of the 20th century, there was no choice. Grenadilla (African Blackwood) was the clarinet wood — 95% of professional instruments, full stop. If you wanted something else, you were either broke or eccentric. (Or French, but I repeat myself.)

That's changing. Grenadilla was added to CITES Appendix II in 2017, meaning international trade is now regulated to prevent extinction. The trees take 60+ years to mature, only 10-20% of harvested wood is usable for instruments, and the primary sources — Tanzania and Mozambique — have faced supply chain disruptions from regional conflict. Large manufacturers have shifted from naturally aging their wood (which takes years) to kiln drying, because there simply isn't enough mature stock to wait. Whether that affects long-term stability is debated (mostly by people on the old Klarinet bulletin board, who will never, ever agree). But what isn't up for debate: the economics are clear, and grenadilla is getting scarcer, harder to quality-control, and more expensive.

Enter the alternatives. Cocobolo comes from Central America — same genus, different continent, different supply chain. It's also CITES Appendix II, so it's not a free-for-all, but at least it represents diversification away from a single species. Mopane comes from southern Africa (Botswana, Zimbabwe, Namibia) and isn't even the same genus (it's Colophospermum mopane). It's also not currently CITES-listed, which makes it the most supply-secure option of the three. As Jochen Seggelke of Schwenk & Seggelke put it: "The resulting diversity takes the pressure off one type of wood and shows that musical sounds do not have to be uniform."

(I 1000% agree: clarinetists should be allowed to sound different from each other. Remember when big city orchestras had a different sound, and you could identify the clarinetist from a mile away? Me too. But I digress.)

So what's the actual difference between these woods?

Physics. According to The Wood Database, grenadilla is the hardest and densest of the three: 3,670 lbf Janka hardness and 79 lbs/ft³. Mopane comes in at 3,390 lbf and 67 lbs/ft³. Cocobolo is the softest at 2,960 lbf and 68.5 lbs/ft³ — about 19% softer and 13% lighter than grenadilla. 

What does that mean for sound? Clap your hands in a tiled bathroom versus a carpeted bedroom. The bathroom throws the sound straight back at you; the carpet absorbs some of it. Grenadilla is the bathroom. Cocobolo is if you carpeted your bathroom. Mopane is the wood that didn’t get the memo. It’s warm like cocobolo, but it still projects like grenadilla. That’s not how this is supposed to work, and yet here we are.

Backun describes grenadilla as having "excellent projection" with a "strong fundamental frequency with prominent harmonics" — what players call "ping." The sound gets into the room. Cocobolo absorbs more vibration before it reaches the audience, so behind the clarinet, you hear more of the clarinet singing back at you while the room hears something warmer and rounder. Out in the audience, the sound evolves differently. (Incidentally, this is why the timbre data on the clarinet dashboards shows Cocobolo as brighter than Grenadilla up close—even though it blends more in the hall.) It's not quieter, but it does have less ping/more blend. Mopane, in my experience is marginally warmer than Grenadilla, and marginally brighter than Cocobolo. In a hall, I can't tell Mopane and Grenadilla apart, TBH.

Now, the cracking question.

The comment/question I hear more than any other when comparing clarinets of different woods is about cracking. Conventional wisdom says (I assume it's conventional since I often hear people say, "well, I heard that") cocobolo cracks more than grenadilla.

But what does the data say? Well as usual, I'll start with an analogy about why things crack.

Think of chapped lips. In the winter it's dry and cold...and if you don't moisturize, they'll crack because your skin loses flexibility. Smile and you've got a split lip — the inside of your lips can expand but the outside skin can't. The analogy isn't perfect, but it's kind of the same physics with your clarinet: The exterior sits in dry room air and becomes brittle. The bore absorbs moisture from your breath and expands. That expansion stresses the brittle exterior. Supple wood flexes. Dried-out wood cracks.

What keeps wood supple? Oil. And here's where the woods differ.

Cocobolo is loaded — often cited at 20-25% extractives by mass, mostly natural oils. That's really high. Those oils act as a moisture barrier, slowing how fast your breath penetrates the bore. That barrier will last, but you have to maintain it; if you let those oils deplete without replenishing them (bore oil), you've lost your buffer. In my view, the "cocobolo cracks more" reputation might come from folks who didn't keep up with oiling. 

Grenadilla is described as "slightly oily" — moderate oil content, but it compensates with massive density. It's the hardest and heaviest of the three, which slows moisture absorption through brute force.

Mopane is also described as "oily", and the technical literature I've read says that "it does not easily end-split during drying; the oily content of the wood might explain this feature." ProSono groups mopane with grenadilla as having "higher oil content" than ebony, putting them in the same stability class.

So the hierarchy isn't grenadilla > mopane > cocobolo. It's more like: cocobolo has the most built-in protection but demands the most attention. Grenadilla and mopane are both equally oily, both equally dense, and both forgiving if you do the basics.

What are those basics? Keep the exterior from drying out (put a humidifier in the case). Don't blow tropical air into an arctic instrument (warm it under your arm and/or between your legs first). Swab OFTEN when it's cold (you're removing the moisture gradient that causes stress). Apply bore oil at the beginning of the dry season each year (you're replenishing the barrier).

In reality, all three woods will crack if you store them in a desert and hit them with a lungful of humid air. All three will hold up if you treat them right. Knowing the differences between species is cool, but it really all boils down to the same thing: maintain your instrument with bore oil (and NOT TOO MUCH). Don't play your clarinet until the outside of the instrument is warm. Swab often. And then, stop worrying so much.