Of major note is a trend towards some very poor quality cork being used. We see that a lot of these cheap corks absorb water and begin to rot. 

This certainly creates performance problems. I have an additional concern that it may create possibly health issues from the growth of mold or bacteria. 

At issue is that if the cork can absorb water, it is also leaking air. If the moisture from the breath gets past the cork plate, so does the air. If the air is getting up past the plate, it is leaking. Even if the air doesn’t escape the North end of the headjoint, it is leaking into the cork. To perform its best, the headjoint needs to seal at the cork plate, not at some undetermined place further up the head.

The rotted corks can be squeezed between the fingers at the Southern end. Replace any rotted cork, or any cork that shows water stains North of the cork plate. 

If you’ve had customers complaining of intermittent performance problems (pitch, response and so forth) with their flute, consider that the flute will begin to perform better once it is “warmed up”. That is explained. Once the cork fills up with condensation from the breath, it now seals better and will perform differently.

Please don’t take the headcork for granted. Check it on each and every flute you service. This will only take a minute, and will improve the consistency of the flute work that leaves your shop. 

See my chapter on headcorks from “Servicing The Flute”.