Calibrate a hygrometer and stabilize your humidor at 69% humidity
The step-by-step salt test, correcting the offset, then adjusting the humidity to around 69%.
Updated October 31, 2026
To calibrate a hygrometer, place it in an environment with a known exact humidity, then compare its reading to this reference. Without this check, it is impossible to know if your cigar humidifier is actually working: an instrument off by a few points is enough to dry out or over-humidify a collection. Here is the complete method, from the salt test to adjusting the humidor to around 69%.
To calibrate a hygrometer, seal it for 12 to 24 hours in an airtight container with a bowl of table salt moistened into a paste: the air inside stabilizes at 75%. The difference between 75% and the display is the correction to apply to every reading. Then adjust the humidor to around 69%.
Why calibrate a hygrometer before any adjustment?
Because every adjustment depends on the measurement: if it is incorrect, every correction will be too. An offset of 3 to 5 points, common in a new instrument, can make a displayed "69%" actually be 64%, or vice versa.
This does not mean the hygrometer is defective: it has a constant offset, which is all you need to know. To choose a model before calibrating it, see our article on the hygrometer, the most underestimated accessory for the serious amateur.
Calibrating does not mean repairing. Most of the time, you do not touch the device: you note the offset and correct it mentally with every reading.
How to calibrate a hygrometer with salt?
Place the hygrometer with moist salt paste in an airtight container: the air inside stabilizes on its own around 75% relative humidity. This is the most economical method, and one of the most reliable.
Materials: a small bowl or cap, fine table salt, a little water, a zip-lock bag or airtight food container, and the hygrometer.
The salt test in 4 steps
How long does the salt test take?
Allow 6 to 12 hours for an electronic model, which reacts quickly, and 24 hours for an analog model. If the value still changes between two readings taken one hour apart, equilibrium has not been reached: wait.
Paste that is too liquid, a poorly sealed bag, or fluctuating temperatures will distort the result. If in doubt, repeat the test.
How to correct a hygrometer's offset?
Calculate 75 minus the displayed value, then apply this figure to every reading. At 72% at the end of the test, the instrument underestimates by 3 points: add +3. At 77%, it overestimates by 2 points: subtract 2.
| Hygrometer type | Test duration | Possible correction |
|---|---|---|
| Analog (mechanical) | 24 hours | Screw on the back on some models; otherwise, note the offset |
| Electronic (display) | 6 to 12 hours | Adjustment menu on some models; otherwise, note the offset |
Adjusting an analog or digital hygrometer
On an analog model equipped with a screw, turn it at the end of the test until it reaches 75%, without taking the device out of the bag. On a digital model, follow the instructions if a correction menu exists. Otherwise, memorize the offset.
Write down the offset and the test date on a label stuck to the back of the device. Recalibrate every six months and after every impact: you will immediately see if the sensor is drifting.
75% calibration kit: when to prefer it over salt?
The calibration kit is a sealed pouch maintained at 75% relative humidity: place the hygrometer inside for 24 hours, then correct the offset as with salt. The principle is identical, without preparation or the risk of paste that is too liquid.
- Salt is suitable if you calibrate infrequently and accept a little preparation.
- The kit is suitable if you want a reproducible result, or if you are monitoring several hygrometers.
- In both cases, calibrate outside the humidor to avoid any exchange of moisture with the wood.
How to adjust the humidity to around 69% after calibration?
Once the measurement is reliable, adjust the regulation until the corrected reading is stable around 69%, at a temperature between approximately 16 and 21°C. This level offers a good balance between regular combustion and protection against mold.
Preparing a new humidor
New, dry cedar absorbs moisture and causes the reading to drop. Before placing your cigars inside, condition the humidor for 24 to 48 hours, with the lid closed, with a moisture source inside. Detailed instructions can be found in our guide to prepare and maintain a new humidor.
Placing the hygrometer and adjusting the regulation
Place the hygrometer in the center or opposite the moisture source, never directly in front of it: the reading would be artificially high. Prefer several small sources spread out over one large one, and do not mix two-way pouches with a standard humidifier. To size your equipment, compare a humidifier and a hygrometer suited to the volume of your humidor.
Read the trend, not the current value
Add cigars in batches and wait 24 to 48 hours after each intervention before correcting. If it stays below 65%, add an additional moisture source; if it stays above 72%, remove one. A variation of 1 to 2 points remains normal on a daily basis.
The workshop's opinion
For an office humidor, we recommend an electronic model such as the CARBONRING electronic hygrometer: its LCD screen displays the humidity and temperature, which speeds up the salt test and daily monitoring. It is available in Gold, Black, or Silver finishes.
For a travel case or box, the PRESTIGE mechanical hygrometer measures 59 × 10 mm: it fits along a wall without compressing the cigars. Like any analog model, allow it 24 hours for testing.
Regarding regulation, the 69% two-way pouches come in packs of three, ready to use: allow one pouch for approximately 25 cigars and replace it when it hardens.
A gift idea for the amateur
A reliable hygrometer and a few regulation pouches: a useful, often forgotten gift for a birthday or Father's Day. Free shipping.
Frequently Asked Questions
Can the salt test be done with rock salt or iodized salt?
Why calibrate at 75% when the humidor aims for 69%?
Can a hygrometer be calibrated without salt or a kit?
When should a hygrometer be replaced rather than corrected?
Does the room temperature affect the calibration?
An accurate measurement, a peaceful humidity
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