Payment OptionsDampen a towel (not dripping wet, but good & damp), then wrap the hygrometer in the towel for 30 to 45 minutes. Then quickly unwrap it and read the humidity. If your hygrometer is perfectly calibrated (few are) it will be reading exactly 100% humidity. Most likely, it will be reading somewhere between 80 and 90%. That's ok - if it's reading 90%, then you know that when it's in your humidor and reading 65, your humidor is really at 75%. Next turn over your hygrometer and adjust the calibration screw accordingly. Wanna get a little more technical? No problem. Luckily, as nature would have it, when salt and water (NaCl and H2O for you studious types), are in a saturated solution at equilibrium, the resultant humidity is 75%. This gives are a fantastic reference point to calibrate our hygrometers. Here's the procedure you should use: Then put the bottle cap of salt and your hygrometer in a see-through, freezer bag. Seal the freezer bag & wait several hours (about six). The humidity inside the bag will be 75%.Compare it to your hygrometer. You will then know exactly how far off your hygrometer is, just like with the damp towel test, above. |