Classical and flamenco guitars tend to be more susceptible to improper humidity than their steel-string and electric counterparts. With a little bit of knowledge and common sense a guitar can be kept in good shape, preserving not only its playability, but its aesthetic beauty and value as well.

The worst threats to a guitar’s ‘good health’ are: excessive dryness, excessive humidity, and sudden changes in temperature/humidity. However, it cannot be emphasized enough that excessive dryness is the most dangerous of the three.

Excessive dryness is a condition that can be caused by natural atmospheric conditions. However, living in a region with high humidity does not necessarily mean the guitar will not be exposed to dryness, because both air conditioning and heating systems can dry out the air.

Most high-quality classical and flamenco guitars are built in workshops where the relative humidity is maintained at approximately 50%. It is therefore recommended that your guitar be stored at this level. Storing your guitar in 40%-70% humidity is generally safe. But anything below 40% can potentially be dangerous. If humidity falls below 40% it is very common for the fingerboard to shrink, causing the frets stick out. If humidity drops below 30% warping and cracking could occur. Depending on the extent of the damage these problems can usually be fixed. If dryness is detected early enough, moving the guitar to a more humid environment will solve the problem. On the other hand, if damage is too advanced the frets may need to be filed down and/or the cracks repaired. The worst case scenario is when the damage is so advanced that the structural integrity of the instrument is compromised. At this point the best option is to take the instrument to an expert repair person to determine whether the instrument is salvageable.

As with all problems, prevention is the best medicine. There are two simple ways of preventing this type of damage from ever occurring. The first is using a humidifier in the room/house the guitar will be kept in. Humidifiers of this kind are sold by most department stores and they come in all shapes and sizes. The second, less intrusive method, is to humidify the case where the guitar will normally be stored. This not only is easier to monitor, but it is also more practical for people who travel with their instrument. If this is your method of choice the Humicase is a great option: it consists of a case with 2 built-in humidifiers, strategically placed to distribute humidity evenly throughout the interior and maintain it at the optimum level.

If you already own a good case you might consider using a case humidifier such as the Oasis Guitar Humidifier or the  Oasis Plus Guitar Humidifier. These products for musical instrument cases work with a humidifier solution; this special liquid, together with the humidifier, helps regulate the humidity level much better than if you were to simply use a sponge with water inside your case. Do be careful to make sure the humidifier does not directly touch the guitar: direct contact with water could damage the wood/finish, or the humidifier itself could scratch the finish.


Regardless of the type of humidification you employ, you should also consider a good dial or digital hygrometer to monitor humidity levels. GSI offers the Humicase Kit, which includes two custom-designed compact humidification units specially adapted for installation in your own guitar case (previously only available with the HumiCase), a mini digital hygro-thermometer, and an 8 oz. size of specially formulated HumiCase Activation Solution for use in the humidification units.

As stated earlier, two other conditions to avoid are excessive humidity and sudden changes in temperature/humidity. Damage from either of these circumstances is much less common, and usually less severe. The most common problem associated with excessive humidity is a slight loss in volume and quality of tone. This can be easily remedied by bringing the instrument back to the appropriate level of humidity. But, DO NOT TRY TO DO THIS QUICKLY OR OVERCOMPENSATE. Some people have tried to remedy this loss of volume/tone by ‘drying out’ the guitar in direct sunlight, only to pay a steep price for the sudden change in temperature and humidity the guitar experiences.

Simply put, avoid any extremes and use your common sense. Do not leave your guitar for long periods of time in direct sunlight; avoid car trunks (which can fluctuate from very hot to very cold quite quickly); do not hang your guitar on a wall (walls have much lower temperatures than the air around them), especially during winter months in cold areas; do not set the guitar next to sources of heat, etc. Very important: if your guitar is exposed to freezing temperatures, do not open the case immediately after going into a heated room! Let the guitar warm up to room temperature while it is still inside the case.

All this may sound like a great deal of trouble for a guitar, but given the size of your investment and the agony of discovering a crack in your fine instrument, we believe that a bit of effort in maintenance will be very much worth the time. If you follow these steps and take good care of your instrument, you should get a lifetime of enjoyment from your guitar.

Both comments and pings are currently closed.

5 Responses to “Care for the Classical & Flamenco Guitar: Part 1”

  1. Jerry says:

    Great article Kai ~ thanks!

  2. Of the many hygrometers I’ve used, only few showed the right relative humidity (RH). In addition, you may have no idea at what RH your guitar was assembled. For this reason, I always tell my customers that the best hygrometer for them to use is the guitar itself:
    If you hold one side of your guitar before your face and look along the width of the back of your guitar, you will see it has a certain doming. This doming will decrease with the RH, because the back will shrink in width, but the length of the back bars inside will not. When you watch the doming of the back a few times, you get to know how it’s normal state looks like. Try to press in the doming with you hand (carefully!) – just to get an idea of the forces involved. So if the normal doming is significantly decreased – in extreme cases the back is pulled completely flat or even caves in – it means red alert.
    If you use a hygrometer make sure to calibrate it at least once a year. And if you want to go professional about humidity, buy a psychrometer, which allows to measure humidity indirectly, but much more precisely.

    • Ed Yourk says:

      Hi Sebastian,

      Thanks for the comments about guitar humidifying. I found your perspective very interesting. May I share briefly what I’ve experienced?

      I’ve noticed a changing of “dome” on my steel string guitar tops (soundboards). I’ve got one that is so caved in (opposite to dome) right now, even though I humidify. I’ve probably left in too long, too dry. Now I’m back-pedalling trying to get it up again. I’ve even tried little posts on the inside of the body from the back to the front, slowly trying to get the top to “dome” again. I’m a guitar teacher and I see so many nicely domed guitar top come in my studio/office here that I know that a bit of doming in front of the bridge of the sound board, looks real nice and seems like a ‘healthy’ thing.
      Any thoughts?
      Ed Yourk

  3. ian says:

    thanks kai
    i liv in an area with up to 100 percent humidity
    how do i bring that down?

  4. Jack says:

    Move to Utah:)


Change language: