Calibrate a hygrometer & stabilize your cellar at 69% RH: 2025 method — quality, luxury, cheap
Humidity is the foundation of a quality cigar humidor. Too low: wrappers dry out, combustion runs wild, aromas fade. Too high: erratic draw, risk of mold and "spongy cigars". The good news? Obtaining and maintaining a target level of 69% RH (Relative Humidity) is simple with a rigorous method and well-chosen tools - without blowing the budget ( cheap when necessary, luxury when it counts). This guide gives you a clear plan: calibrate your hygrometer , prepare (season) the humidor, stabilize at 69% RH, then maintain without thinking about it.
Why calibrate first (and recalibrate later)
An inaccurate hygrometer condemns you to chasing meaningless numbers. A deviation of 3–5 points is enough to cause your cellar to drift from a "perfect 69%" to a zone that is too dry or too humid. The pro rule: calibrate upon receipt , then check every 6 months or after an impact (moving, falling). Some humidification pack manufacturers explicitly recommend this periodic recalibration routine and offer ready-to-use 75% RH kits , which simplify everything.
The 3 families of hygrometers (and which one to choose)
- Analog (needle): Charming, but sensitive to shocks and temperature variations. We keep it for aesthetics, not for absolute precision. Calibrable, but the offset shifts over time.
- Digital standard: Best value for money : decent accuracy (±2–3%), readable, often with temperature. Ideal as a primary reference .
- Digital “pro”: More stable sensors, multi-point calibration, sometimes recording. Luxury choice, useful for large cellars or demanding amateurs.
Double safety tip: In a large cellar, install two sensors in different areas (top/bottom). Any differences will alert you to poor air circulation.
Calibration: two reliable methods
1) The salt test (DIY, inexpensive, very reliable)
This is the best-known DIY method: in a perfectly closed volume, a stable microclimate at ≈ 75% RH is created using salt and water.
Materials : a small container, table salt, a few drops of water (to obtain a wet paste), an airtight bag or box, the hygrometer.
Steps
- Mix salt + a few drops of water to obtain a moist paste (neither dry nor submerged).
- Place the small container + hygrometer in the airtight bag/box .
- Wait 24 hours at a stable temperature . The room will naturally stabilize around **~ 75% RH**.
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Read the value of your hygrometer:
- If it shows 75%, it is correct.
- If it shows 72%, record +3% as a corrective offset .
- If it shows 77%, record –2% as the offset.
- Apply the offset (in the device if it allows adjustment, or mentally at each reading).
Specialized brands and stores also market sachets calibrated at 75% RH which exactly reproduce this “salt test” principle in a turnkey version.
2) The calibration kit (turnkey, precise, fast)
You place the hygrometer in a sealed bag at 75% RH for 24 hours , then adjust the offset to read 75%. Some vendors recommend recalibrating every 6 months .
Bonus: Some kits offer two points (e.g. 32% + 75%) to check sensor linearity.
Pro tips
- Perform the calibration away from the cellar to avoid humidity exchange.
- Note the calibration date on the back of the device.
- Avoid hot areas (above a radiator) and drafts : measure under usage conditions.
69% RH: Why this target works so well
The old "70/70 rule" (70% RH at 70°F) remains a classic, but more and more enthusiasts are going slightly lower, around 65–69% , for a cleaner draft, less over-humidification, and less risk of mold. 69% RH has become a very popular modern standard for wooden humidors and airtight containers (Tupperdor, acrylic box), with variations at 65% (drier/easy combustion) and 72% (very dry outdoor environment, highly absorbent wood, personal preference).
Preparing (seasoning) the wooden cellar: the step that is neglected too much
Spanish cedar isn't just about fragrance: it absorbs and releases moisture, stabilizes the microclimate, adds a subtle scent, and deters tobacco beetles . But "new" wood is dry and will first suck up moisture from the cellar; without preparation, you're chasing values.
Simple method
- Clean the cellar (dust) with a dry cloth.
- Place 2–4 seasoning packs (often 84% RH ) depending on the size of the cellar, without wiping the wood with water (risk of swelling/warping).
- Leave for 10–14 days without opening.
- Replace with your 69% RH packs, close 48–72 hours.
- When the calibrated hygrometer displays stable (±1–2 pts over 24–48 h), insert the cigars.
Travel shortcut: For a travel case , a single 69% pack is often sufficient (8g for 3–5 cigars). As a general rule, count 1× 60g per ~25 cigars for a humidor, spreading the packs out.
Stabilize at 69% RH: the routine that works
- Reliable reference: Use a calibrated digital hygrometer , ideally placed in the middle of the cellar (neither stuck to the lid nor against a wall).
- Bi-directional humidification: Opt for regulator packs that add and remove humidity as needed. This is the cleanest and most stable way to reach 69% (or 65/72% depending on your preference).
- Distribution : It is better to have several small packs spread out than one large one : the air circulates better and the regulation is uniform .
- Progressive loading: Avoid going from 0 to 100 cigars at once. Tobacco is hygroscopic : it absorbs/releases moisture. Add in batches , monitor the impact, compensate with an additional pack if the RH drops.
- Temperature : Keep it cool (18–21°C). A warm cellar promotes mold and flavor buildup.
- Patience : After any intervention (adding cigars, changing packs), allow 24–48 hours before interpreting the trend.
What to do if it goes wrong?
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Too low (≤ 65%)
- Add 1 pack (or temporarily increase to 72% if the environment is very dry).
- Check for leaks (seals, cover).
- Check that you haven't added a lot of dry cigars at once.
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Too high (≥ 72%)
- Remove one pack and ventilate for 5–10 minutes (without excess).
- Keep the cellar away from heat sources .
- Check the hygrometer (bad calibration is a classic).
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Unstable reading
- Move the hygrometer away from a wall or pack.
- Test the hygrometer at the 75% kit to check for drift.
Great debate: 65, 69 or 72%?
- 65% : drier sensation, easy draw, even combustion; useful for very dense cigars or for long aging.
- 69% : modern balance (flavor, combustion, anti-mold safety) and the most popular for a large majority of cellars and airtight containers.
- 72% : Useful if the outdoor environment is very dry (very hot winters, desert climates) or if your new wooden cellar still absorbs a lot. Personal preference and local climate make the difference.
Spanish Cedar: an active “component”
Spanish cedar is popular because it:
- Regulates moisture by naturally absorbing/releasing.
- Lightly perfumed and enhances the bouquet with aging.
- Deters tobacco beetles and has good natural resistance to mold.
- Stabilizes the cellar over time.
Beware of poorly dried wood: insufficiently dried cedar can exude a sticky resin over time - hence the importance of reputable suppliers.
Simple maintenance schedule
- Every week : check the hygrometer (reading after 24 hours without opening).
- Every 2–4 months : feel the packs; if they harden significantly, replace them (duration varies depending on volume, opening, season).
- Every 6 months : quick recalibration with the 75% RH kit.
- Every year : inspection of seals and gentle dusting.
Common Mistakes (and Fixes)
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Wipe the wood with water to “go faster”
→ Risk of swelling and deformation . Prefer passive seasoning with dedicated packs.
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Loading too much at once
→ Tobacco absorbs moisture and lowers RH. Introduce in batches and compensate.
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A single large pack in the center
→ Heterogeneous regulation. Distribute several packs.
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Seeking perfection to the tenth of a point
→ ±1–2 pts over 24–48 h is perfectly normal .
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Forget the temperature
→ A cellar that is too hot distorts perception and increases the risk of mold .
Frequently Asked Questions
Is 69% RH “better” than 70%?
Not absolutely "better," but more forgiving : many enthusiasts find a more consistent draw and less over-humidification around 65–69%. Humidity brands list 69% as the most popular value for premium cigars.
I live in a very dry climate: isn't 72% safer?
This can be justified when the ambient air is "pulling" very strongly. However, monitor the combustion (risk of capricious draft). If you notice persistent over-humidification, lower it to 69% .
How many packs for my cellar?
Rule of thumb: **~ 1× 60g / 25 cigars** (distributed throughout the humidor). Adjust according to your openings and the season.
How do I know if my hygrometer is telling the truth?
Perform the salt test (≈ 75% RH) or use a dedicated 75% kit for 24 hours, then adjust the offset. Recalibrate every 6 months .
Does Spanish cedar really change anything?
Yes: humidity control, stability , subtle aroma , and beetle deterrence —it's the benchmark for high-end cellars.
Resources & selections Atypical Workshop
A calibrated hygrometer , meticulous preparation of Spanish cedar, correctly distributed 69% packs and a light routine : this is the secret to a stable humidor, respectful of your cigars and pleasant to manage on a daily basis. You will thus have the consistency of a luxury humidor, without spending your weekends or your budget there - and above all, the pleasure of opening the humidor knowing that each cigar is ready to deliver the best of itself.
