How to Calibrate a Humidor Hygrometer: Ensuring the Right Humidity for Your Cigars

A cigar humidor preserves stogies by maintaining them at just the right humidity. And a hygrometer is how you keep this humidity ‘just right’.

Cigar hygrometers measure the humidity in a humidor. But their accuracy isn’t always a given, so it’s important to know how to calibrate a humidor hygrometer. Here’s an in-depth guide to the process and how to do it right.

What is a Humidor Hygrometer?

A humidor hygrometer is a device you put in a humidor to measure the humidity inside it. More specifically, the hygrometer measures relative humidity (RH).

The term ‘relative humidity’ requires some explanation. The air naturally contains water vapor. However, the exact amount of water vapor the air can hold depends on the temperature.

So, RH measures how ‘full’ the air is with water vapor, given the specific temperature. That’s why RH levels are recorded as percentages. It’s also why some hygrometers provide temperature readings, too. These give you a fuller picture of what is happening in your humidor.

A hygrometer uses a screen, dial, or gauge to clearly display the current RH level. This enables the user to regularly check readings with ease.

Why is Calibrating Your Hygrometer Important?

A hygrometer’s readings can become less accurate over time. This is a big problem, as you don’t want to inadvertently leave your stogies in the wrong storage conditions.

Your cigars need the optimal level of moisture. When humidity is too low, it can dry out the tobacco. As a result, the essential oils on those stogies can evaporate, ridding them of their flavor.

Conversely, excessively high humidity risks dampening those sticks. This is when cigar mold can quickly spread. An improperly stored cigar, whether too dry or too wet, can also easily crack or split.

Analog vs Digital Hygrometers

An analog hygrometer is the more traditional, ‘old-fashioned’ option. Often, an analog unit will have a circular dial reminiscent of a clock. It’s lined with RH percentage numbers, while a needle points to the correct one.

Analog hygrometers are generally cheaper to run than their digital counterparts. That’s because the latter are more hi-tech. For example, they rely a lot more on electricity.

However, digital hygrometers win out when it comes to accuracy. They also tend to be easier to use. The RH is usually represented as a simple, easy-to-read number on a screen.

It’s crucial to know how to calibrate a hygrometer whether it’s analog or digital. Nonetheless, you will likely need to do it more often when you go down the analog route.

When You Should Calibrate Your Hygrometer

How often you need to calibrate depends on whether you’re going analog or digital. With digital hygrometers, once a year can suffice. Analog hygrometers go out of whack more easily, so aim to calibrate those at least every six months.

The ideal frequency of hygrometer calibration also depends on other circumstances. Like when:

• Seasons change: As the weather warms up or cools down, your humidor’s humidity can become less predictable.
• You get a new hygrometer: Don’t simply assume that every new one you buy will be fine-tuned straight out of the box. That even applies to ‘pre-calibrated’ models.
• Readings are inconsistent: If RH levels seem to keep fluctuating for no obvious reason, go ahead and recalibrate. It’s possible that the device alone is to blame.

If you’ve got the time, though, calibrate every month. That way, when readings do start becoming less reliable, you can quickly nip the issue in the bud.

The Salt Test Explained

This is the most common humidor hygrometer calibration method. It’s simple to do and requires just a few easy-to-source items.

Why the Salt Test Works

The hygrometer salt test entails mixing salt with water. However, be careful how much of each you include. A well-balanced ratio of salt to water creates an environment of 75% relative humidity. The RH will stabilize at this level, allowing for effective calibration.

What You’ll Need

Obviously, you’ll need the hygrometer itself. Head to your kitchen to find a salt shaker, a teaspoon, and a small cup. You’ll also need an airtight container and water from your tap.

How to Do the Salt Test

Measure out a teaspoon of salt and pour it into the cup. Moisten the salt by adding a few drops of water. You don’t want to dissolve the salt. The idea is to instead create a paste-like consistency.

Next, place the cup beside your hygrometer in the airtight container. Leave alone for six to eight hours, then read the hygrometer’s humidity figure. Ideally, this figure will be 75%. If it isn’t, adjust the hygrometer to bring its reading to 75%.

Checking and Understanding the Results

Often, it’s easy to read the RH number on a hygrometer. What’s not always so obvious is what the figure actually means for your cigars. Here’s some guidance on how to interpret the reading:

What a Correct Reading Looks Like

To keep your stogies fresh, the RH must hold steady at about 70%. This is the ideal amount of water vapor you want in the humidor. If the RH is significantly above 70%, the environment is too moist. If it’s far below 70%, the storage conditions are too dry.

How Much Difference Is Normal

Your hygrometer’s RH readings don’t need to be exactly 70% or stay that way. It’s normal for a humidor’s humidity to fluctuate in the region of 65-75%.

You only need to worry when the RH levels start consistently falling outside this 10% range. When that happens, some hygrometer calibration is in order.

How to Adjust Your Hygrometer

The adjustment procedure differs depending on the type of hygrometer. If you don’t know how to adjust your own hygrometer, check the instructions that came with it. If you can’t find any, contact the manufacturer for advice.

Here is how adjustment methods differ between analog and digital hygrometers:

Adjusting an Analog Hygrometer

This is a mechanical process, as it involves physically rotating the needle. Turn the hygrometer over and look at its back. There will be a screw you can turn to adjust the needle. You’ll need a small screwdriver for this job.

Adjusting a Digital Hygrometer

Exactly how you do this depends on the model. Perhaps yours has a specific button you can long-press to activate the calibration. Also, watch out for ‘plus’ and ‘minus’ buttons enabling you to tweak the indicated RH figure.

Not all digital hygrometers are adjustable. This is often the case with those built straight into the humidor. However, if your hygrometer isn’t adjustable, you can still memorize the RH difference.

For example, the RH readings might be ten percentage points lower than the actual RH. So, when you use the hygrometer, you can add those percentage points to the RH figure it displays. This will leave you with the true RH.

Other Ways to Calibrate a Hygrometer

The hygrometer salt test is popular, but it’s not the only option. Here are some other humidor hygrometer calibration methods worth considering:

Using Humidity Packs

The Boveda brand is famous for its humidity packs. You can easily regulate the humidity of a humidor by adding Boveda packs to it. It pays to know how to calibrate a humidor hygrometer with a Boveda pack. But you need a very specific type.

That’s the Boveda One-Step Hygrometer Calibration Kit. This is a sealable bag big enough to hold your hygrometer. Once the device is in there, seal the bag closed. Now leave for at least 24 hours at room temperature.

After all this, a successfully calibrated hygrometer will read 75% RH. If your hygrometer doesn’t quite make this grade, adjust accordingly. Alternatively, note the difference.

Paper Towel Test

Dampen (but be careful not to soak) some paper towels. Wrap your hygrometer in them before leaving them there for about 30-45 minutes. Then, unwrap the hygrometer to check its RH reading.

The hygrometer is perfectly calibrated if it reads 100% RH. If it’s higher or lower than this, the calibration is off. For example, if the RH is 85%, it’s 15 percentage points lower than it needs to be. You can account for this difference, such as by adjusting the hygrometer if possible.

Accurate Readings, Better Cigar Storage

It’s well worth setting aside time to learn how to calibrate a humidor hygrometer. Once you’ve committed that knowledge to memory, it can be a quick and easy job to take care of.

Before long, the hygrometer calibration process can feel like second nature. Doing it regularly will give you immense peace of mind. It’s a great way to keep your prized cigars fresh for when you smoke them.

Of course, it’s also important to buy great-quality cigars in the first place. You’ve got plenty of premium stogies to choose from here at Swiss Cuban Cigars. Feel free to browse the selection here on our website. We deliver to a wide range of international territories.