How to Calibrate a Hygrometer for Cigar Humidors
Hygrometers come in analog and digital models. They both have the same function, reading the relative humidity in a cigar humidor. The less expensive analogs have a small adjustment screw for calibration. Cigars keep for many years in a humidor with 65 degree temperatures and 65 to 70 percent humidity.
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Things You'll Need
- Hygrometer
- Dish or cap
- Salt
- Water
- Lidded container
- Zip lock bag
- Flathead screwdriver
- Damp cloth
Instructions
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1
Get a small dish or cap and pour 1 tsp. of table salt in the container. A cleaned plastic bottle cap or laundry soap cap works well.
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2
Add water to the salt. Use only enough to wet and dampen the salt without dissolving it.
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3
Place the salt and water container in a sealed environment. Use a plastic food container with a lid or a zip lock bag large enough to hold the dish or cap with the hygrometer.
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4
Put the hygrometer carefully inside the container near the salt solution.
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5
Seal the plastic zip lock bag or place the lid over the container. Leave air trapped inside. Allow 7 to 8 hours before re-opening.
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6
Take the hygrometer out and read the humidity level. A reading of 75 percent humidity means the hygrometer measures correctly. The salt and water solution always reaches this percentage.
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Adjust the screw, with a small flathead screwdriver, at the back of the hygrometer to 75. With no setting screw, note the deviation to calculate the humidity in the future. For example, if the humidity measured 65 percent, you know that the hygrometer reads 10 percent less than it should.
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Tips & Warnings
Test your humidor's hygrometer every 6 months to ensure the right humidity calibration for the cigars.
Digital hygrometers typically don't have a way to calibrate the measurement. The factory calibrates before shipping. The same test with the salt and water lets you know if the device reads accurately. If not, note the difference and add or subtract the number to obtain the correct reading.
A quicker, but less accurate calibration, takes about an hour. Dampen a cloth with water and wrap it around the entire hygrometer. Remove after the hour and adjust the screw to read 96 percent relative humidity.
