Why 70°F / 65% RH Is Better Than 70/70
For decades many of us have defaulted to the “70/70” rule - 70°F (~21C) and 70% relative humidity - as the baseline for cigar storage. It’s simple, memorable, and has served hobbyists and collectors well. But as more hobbyists, manufacturers, and tobacconists test variables like cigar construction, wrapper oils, and long-term aging, a clearer picture is emerging: a slight shift to 70°F and 65% RH (what some are now calling the “135 Rule”) often produces more consistent burn, better draw, and cleaner flavor development over time.
Why 70°F / 65% RH?
- Balance of moisture and combustion: 65% RH keeps cigars sufficiently pliable without adding excess surface moisture that can hamper even lighting and burn. Too much humidity can slow combustion and encourage uneven burn.
- Less mould risk, more predictable aging: Lower RH reduces the marginal risk of mould and tobacco beetle concerns in warmer storage situations, while still allowing natural aging and flavour melding
- Better wrapper and binder harmony: Many modern wrappers - especially oily Connecticut Broadleaf and Connecticut shade leaves - show fewer bloom/scumming issues and preserve surface oils more predictably around 65% RH
- Consistent draw and burn stability: Slightly drier cigars (relative to 70%) tend to draw a bit more freely and maintain a steady cherry. For many smokers that means improved on-smoke experience with fewer re-lights and touch-ups
Why keep the temperature at 70°F?
- Temperature primarily affects chemical reaction rates in aging and the risk window for tobacco beetles. Around 70°F (~21C) you’re in a comfortable zone for aging without accelerating volatile loss or increasing pest risk
- Consistency matters: fluctuations cause condensation and RH swings. Stable 70°F paired with steady RH is the goal
Practical Tips for Switching to 70 / 65
- Adjust slowly: If your humidor sits at 70/70 now, reduce RH in 1–2% steps over several weeks to avoid shocking wrappers or binder seams
- Calibrate your tools: Use a reliable digital hygrometer with a thermometer - ideally two-point calibrated - and spot-check weekly while making the change
- You can also Calibrate your digital hygrometer with a Boveda Calibration Kit
- Humidification choices: If you use gel beads or electronic humidifiers, set or refill to target 65% RH. For traditional Boveda-style packs, use the 65% packs; they’re simple and effective
- Consider cigar type and duration: If you smoke frequently, 65% is ideal. For long-term aging (multiple years), some collectors prefer slightly higher RH during initial settling for very dry cigars, then move to 65% for longer storage
- You can also try to stagnate some aspects of cigar-aging by keeping them at a lower temperature; but this is expert-level and takes some time to perfect
- Monitor seasonal swings: In winter, indoor heating can drop RH; in summer, HVAC systems can tighten things. Maintain active monitoring rather than assuming the set-and-forget approach
- If you store more than just a week or few weeks worth of cigars you plan to enjoy; then never rely on the old analogue style hygrometers; they are pretty useless
- Travel and short-term storage: For travel humidors, aim for 65% as well - less chance of condensation and better performance in fluctuating cabin or car temperatures
What to Expect on the First Few Smokes
- Slightly crisper draw, more defined flavours: Many report better clarity and less “damp” taste
- More predictable burn lines and fewer canoeing issues caused by overly moist wrappers
- Wrapper oils remain stable - less surface residue or “bloom.”
When 70/70 Still Makes Sense
- Very dry cigar intake: If your cigars arrive unusually dry (below 60% RH), you may briefly use 70% to rehydrate more quickly, then step down to 65% for maintenance
- Personal preference: Some smokers enjoy the mouthfeel and slower burn of slightly wetter cigars. If you prefer that profile, keep what works for you
Troubleshooting
- If cigars feel brittle after dropping to 65%: raise RH by 1–2% and monitor; abrupt drops may cause dryness
- If you see white fuzzy growth: increase airflow, lower RH slightly, and inspect. Mould is rare at 65% but can appear with poor circulation or contaminated wood
- If burn becomes too fast or aggressive: check for over-dryness (RH <60%) and slowly re-hydrate gradually
Bottom Line The 170°F / 65% RH guideline - the “135 Rule” - keeps things simple while improving burn stability, flavour clarity, and aging predictability for many cigars. It’s not a one-size-fits-all law, but it’s a practical, evidence-backed update to the old standard.
Try gently adjusting a portion of your humidor to 65% and compare a few sticks. Your palate (and your ash) will tell you quickly whether the switch works for your collection.
Enjoy your Sunday cigar - and let me know if this short checklist to convert your humidor to 65% RH has been a benefit in your own collection.