Educating yourself about the effects of humidity on your guitar is one of the best ways to insure its integrity and lifespan. Your guitar is a living, breathing entity that is easily affected by its surrounding environment. Although the woods used in the making of your guitar are carefully dried and seasoned, they still breathe, expand, and contract. We recommend storing your guitar inside its case when not being played, and keeping it within a temperature range of 60°F-85°F, and a relative humidity of 40%-60%. Our guitars are built at about 50% humidity, so keeping the guitar as close to this relative humidity as possible is ideal. However, a certain level of humidity fluctuation is unavoidable, considering weather shifts etc., so as long as these fluctuations are kept within +/- 10%, the guitar will remain healthy. A hygrometer stored in your case will provide you with both of these measurements.
In wet or humid climates, the wood can soak up excess moisture from the air and dull the sound of the guitar. It can also loosen the glue used during construction, and/or lower the action of the strings, which can cause buzzing (link to article?). If your guitar or ukulele seems to be bulging or swelling, it is most likely over-humidified. A particularly rainy season can be the culprit!
If your guitar appears to be over-humidified and you use a HumiCase or other humidifier, you will want to discontinue use of the HumiCase pods or other humidifier until the humidity inside the case normalizes. You can also leave the case open for a while, assuming the relative humidity in the room is normal or equal to about 40%-55. You can even use a blow dryer to to dry the case out (as cases can hold moisture in the padding and lining) or put some desiccant pouches in the case (these are small pouches often included with products coming from overseas).
In dry climates, cold weather, or artificially heated or cooled rooms, your guitar's wood can lose its natural moisture. One of the first rules of thumb is to not leave your guitar in any situation in which you yourself would not be comfortable, such as inside a hot vehicle, next to a radiator, or in direct sunlight. As your guitar dries out, the wood shrinks. One of the first symptoms you will notice is the fret ends jutting out from the side of the fingerboard. If the guitar continues to lose its moisture, you will notice lower action as the top begins to flatten, and ultimately, your guitar will crack. Drying out can also lead to delamination: as the wood shrinks, it pulls away from the finish into the fret ends, and the fret ends force it away from the wood. Just as over-humidifying can affect your guitar's tone, dried out guitars can also begin to sound "dead."
If you are primarily a steel-string player, and you keep your guitars in the same room, please see our companion article, Nylon vs. Steel String Guitars for more information on how and why these two types of guitars can behave very differently in the same climate.
The best way to keep your guitar in top shape is by using some type of in-case humidification, and monitoring the humidity levels with a hygrometer. Aware of the sensitive nature of our guitars, Cordoba Music Group developed the HumiCase brand, a few different kinds of self-humidifying cases built specifically for Cordoba Guitars. We offer an upgraded limited lifetime warranty when you purchase a HumiCase within seven days of purchasing your Cordoba Guitar. While our HumiCase website is under construction, please visit this page more for information on which HumiCase is right for you!