“Captain Obvious:” How Water Keys Work

Allow me to interrupt your holiday recuperations or Black Friday shopping for just a moment to address a pet peeve of mine. I titled this little piece “Captain Obvious,” but given the prevalence of this misunderstanding among my students and others, clearly this is not so obvious after all. I want to address a simple, slightly disgusting, but vitally important part of playing a brass instrument: emptying the water keys.

Honestly, this isn’t as gross as non-brass players in particular seem to think. The colloquial term “spit valve” is funny, but not particularly correct. While there is a small amount of saliva in the liquid that collects in the various nooks and crannies of brass instruments, the majority of it is condensed water vapor, just like the water droplets that form when one breathes warm air on a mirror or window. While there are valid reasons to collect this material in a spittoon, cup, or garbage can in certain situations rather than emptying it on the floor, those have to do more with the tendency of wet spots on thick carpet to promote mildew, not with the unsanitary nature of “people’s spit.”

spitMy real concern this morning is not with the composition of the condensate emptied from the water keys, but rather with how the water keys actually work. To me, the most disturbing part of how students empty water keys is not what comes out of them but how students try to operate them, namely by blowing vigorously and loudly through the instrument in order to force the water to exit. This is not only distracting; it is often ineffective when compared to quieter methods. Consider the picture of a water key here (sorry for using a trumpet; it was the clearest image Google returned). Although there are a few variant designs, the usual water key is a slightly raised opening made at a point in the tubing where condensation tends to collect, and sealed with a small piece of cork or rubber that is held in place with a lever and spring which can be opened periodically to release water from the instrument. Gravity dictates that the water collects at low points in the instrument’s tubing, so this is where water keys are typically placed.

At this point more technically minded readers might ask, “if gravity makes the water collect at the instrument’s low points, wouldn’t gravity alone make the water exit the opening when a water key is engaged?” The answer is YES. Although there are times when a bit of vigorous blowing or tilting of the instrument is needed to move the water to a point where it can exit through a water key, once the water is there it will exit through the hole without any blowing at all. Humorously, I have even seen students look to see where the water key is, open it, and then have all of the water run out before they (loudly and unnecessarily) blow through the instrument. Not only is the loud noise of blowing to empty the “spit” unnecessary; it can even be counterproductive if the air is blown so vigorously that the water actually moves past the opening rather than exiting the instrument, and then returns to its former place when the water key is disengaged. Then the familiar sound of gurgling water continues to mar one’s performance.

Of course, there are cases in which engaging a water key without blowing will not cause the water to exit. As I have already mentioned, tubas and horns are notorious for having bends in the tubing without water keys that necessitate some blowing and tilting of the instrument in order to remove the water. Many instruments have tuning slides without water keys in the valve system that must be removed in order to empty water. I have even noticed that a bit of water can collect between the two valves in double-valve bass trombones, in which case removing one of the tuning slides and blowing a puff of air to force out the water is needed. Except in instances like these, if the condensate will not exit the instrument through a water key with very little or no blowing the likely culprit is “cheese” or “gunk” caused by food particles collecting in the instrument and promoting…growth. In that case your first step should be to get a professional cleaning, and after that to buy a toothbrush.

“Spit valves” are (usually) not as gross as people think, but incorrect operation can be a distraction. Instead of loudly and obnoxiously blowing through the instrument just open the water key and allow gravity to do its thing.

About Micah Everett

Micah Everett is Associate Professor of Music (Trombone/Low Brass) at the University of Mississippi, Principal Trombonist of the North Mississippi Symphony Orchestra, Interim Music Director at College Hill Presbyterian Church, Assistant Editor (Audio/Video Reviews) for the International Trombone Association Journal, and an S.E. Shires trombone artist. He is the author of THE LOW BRASS PLAYER'S GUIDE TO DOUBLING, published by Mountain Peak Music, and released two solo recordings, STEPPING STONES FOR BASS TROMBONE, VOLS. 1 and 2, on the Potenza Music label in 2015 and 2022, respectively. In addition to his professional work, he maintains an avid interest in the study of the Bible and of Reformed theology. He holds doctoral and master's degrees in music from the University of North Carolina at Greensboro, a bachelor's degree in music education from Delta State University, and a certificate in systematic theology from Puritan Reformed Theological Seminary.
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