Cool Storage for Cigars – Part 2

With more cigar lovers using wine coolers as humidors, we set out to explore the topic of cool storage in greater depth. Let’s start off with an inevitable physical reality: air holds water in suspension, and the warmer the air, the more water it holds.

At 68 degrees Fahrenheit (20°C) and 70 percent relative humidity, a cubic meter of air holds 12.1 grams of water. If this air is cooled, relative humidity rises accordingly, because cooler air holds less water than warmer air.

As long as the cooled cigar storage area is hermetically sealed from the outside environment, eliminating any risk of fluctuation in temperature or relative humidity, stored cigars are in good shape. But what happens when the cooled cabinet is opened?

Let’s use some numbers from the average summer. Humidor conditions: 59 degrees (15°C) and 70 percent humidity. Conditions in the humidor’s external environment: 77 (25°C) degrees and 60 percent relative humidity. When the humidor is opened, warm air streams in.

After the door has been closed, this warm air has now been cooled by about 18 degrees. Result: the cooler air can no longer retain the same amount of water, leading to condensation in the humidor. This example may seem extreme, but it illustrates the physical interrelation between the two factors, temperature and humidity.

Another frequent problem: despite being able to regulate temperature electronically, many humidors with a cooling function just can’t remove enough humidity from the air. And how do the manufacturers of such cabinets respond? One way is to engineer the humidor so that it blows out air that is too moist.

But a cabinet is not an elastic balloon out of which air can simply be released; it’s inevitable that some outside air will flow in as well. This then leads to an extremely high air flow rate, directly in opposition to the goal of long-term cigar storage: allowing in as little fresh air as possible.

Practical Recommendations

Here are some suggested guidelines for cigar lovers wishing to keep their cigars in cool storage:

• Never put the cooled humidor in a very warm room, unless the room is dry (under 40% relative humidity).
• Keep the humidor in a cooled room with little temperature differential between the humidor and the room itself. Simply applying moisture to the humidor in a deliberate, methodical way works very well.
• Some walk-in humidors feature both an air conditioner and a humidifier. Just make sure that the setup also features a de-humidifying function (ideally one that is continuously adjustable). This allows the cigar enthusiast to carefully control the balance between de-humidification and cooling, keeping moisture variations in check. Any water removed from the air through the cooling mechanism is then fed through the humidifier, alleviating the need to constantly refill the unit. It’s crucial that the climate control unit removes more water from the air than the corresponding increase in moisture due to cooling of the air. In other words, without additional humidification the cooled air could fall short of a relative humidity of 70%.
• The most professional solution would be to create a separate chamber of air precisely at the desired humidity level and temperature, and to direct it into the humidor (removing it when necessary). Ideally, the entire system is a closed cycle, preventing the introduction of fresh air as much as possible. Of course, because of the large amount of space required and the high cost of implementation, these types of solutions are often prohibitive for even the most passionate cigar lover.

Conclusion

Technology can be beneficial when storing cigars, as long as it is truly able to stabilize storage conditions and save the cigar lover time. But when it comes to cooling, technology often does the exact opposite of what it is meant to. When storing wine, constant temperature is more important than constant air humidity; it’s the exact opposite with cigar storage.

Assuming that relative humidity remains constant, the occasional temperature fluctuation does not have a big impact. A moderately cooled storage space (65-68°F or 18-20°C) makes the most sense for long-term storage of cigars, slowing down the conversion of aromas and flavors and allowing them to develop complexity. However, relative humidity should also be dialed back as well.

Much more important to the cigar than constant temperature is constant air humidity. As a basic principle, it is optimal to store cigars at a constant temperature and under consistent air humidity.

To part one of this article.

Relative Humidity (R.H.)

Photo: Wolfgang Hametner

A cubic meter of air can absorb a certain amount of water in its gaseous state (water vapor). At 68 degrees Fahrenheit (20 °C), this maximum amount is 0.61 oz. water. Add any more moisture, and the air becomes saturated with water, bringing relative humidity to 100 percent. What’s more, this water is now no longer suspended as vapor; instead, it forms visible condensation on walls or other surfaces.

This article was published in the Cigar Journal Autumn Edition 2013. Read more