Expert: James Yee - 5/13/2009

Question
QUESTION: Hi James,

I just had a question regarding digital hygrometers.   I got sick of my analog which was giving me more than enough stress so I went out and bought a digital one today.

So far, im pretty impressed at how much better the digital is over the analog.

My question is this.  It seems that the accurate temperature is given almost instantaneously, but im not so sure about the humidity.   

I put in the hygrometer about 10-15 minutes ago, and the temperature is at 72 degrees, but the humidity is at 38%... so im kind of praying that it is a slow reading and will gradually rise.   But im also a little freaked out at the fact that my humidor is that dry.

I refilled the PG formula for my humidifier and also added an extra one.

While we're on this topic, is there such a thing as too much Propylene Glycol formula?   Cause it stabilizes at 70%, so is there harm in adding too much PG or adding another humidifier?

thanks for the help!

ANSWER: Hi Andrew,

Make sure your hygrometer is not obstructed by any humidor components or cigars as they might cause an improper reading.  Digital hygrometers are pretty sensitive so you should be able to pick up an accurate reading within 10 minutes or so.  38% humidity is too low so if the hygrometer's reading doesn't improve, conduct a salt test on your hygrometer to make sure that it's accurate and not defective.  (If you need salt test instructions, please search my question archive or feel free to just ask me and I will gladly repost it for you.)  If the salt test proves your hygrometer to be accurate, you will need to re-season your humidor.  

As for PG, too much PG can indeed be a bad thing.  PG basically forms a liquid membrane over the surface of the water to restrict evaporation and this is what regulates 70% humidity.  Adding too much PG however, can cause the water to evaporate through a thicker layer of PG and this will cause slow and low humidity performance.  Too much PG in a humidification device will also take away space for your distilled water.  The less amount of water your humidifier can hold, the more frequent you will need to refill it.  

When adding PG to your humidification device, always start with a 50/50 ratio.  50/50 should be enough to create 70% humidity but in some cases, you may need to fine-tune the mixture to achieve 70%.  If the humidity is too high after adding PG, add a few drops more of PG.  If the humidity is too low after adding PG, add more distilled water to dilute it.

Hopes this answers your questions. As always, if you have any more questions, please feel free to just ask and I will be happy to help.

Regards,
James

---------- FOLLOW-UP ----------

QUESTION: Thanks for the quick reply James

Im currently not using just 100% propylene glycol, but im using a premixed 50/50 solution

Ive been adding the 50/50 solution, but should I add distilled water instead?

Also, its been well over an hour, and its only at 48%.   This puzzles me as I callibrated by analog hygrometer with the salt test, and that said it was at 72%, however the digital says 48%.   Quite weird

on the box for the digital hygrometer, it also states 10 second refresh rate.   Does that mean it can determine both humidity and temperature in 10 seconds?

thanks again for the help!

ANSWER: Hi Andrew,

PG can last a long time inside your humidor (on average 2 years before it loses its effectiveness) so you only need to add a 50/50 mixture just once.  After this, just add distilled water to your humidification device when needed.  As I mentioned earlier, a 50/50 mixture should create 70% humidity.  If the humidity is still too high, purchase a small bottle of propylene glycol to fine-tune your mixture.

50/50 mixtures are only helpful when you constantly have high humidity in your humidor (75% humidity or greater).  If you never had high humidity problems, 50/50 mixtures and PG is not necessary.  If you haven't had any problems with high humidity so far, try using distilled water only in your humidification device.  (Be sure to thoroughly rinse the 50/50 solution off your humidification element with distilled water.)

The "10 second refresh rate" most likely applies to both temperature and humidity.  You may have to check the instruction manual or fine print on the box for details.  Also, if you haven't seasoned your humidor for a long time (or never seasoned it at all), you should season it.  This will allow your humidor to absorb and regulate humidity more effectively.

Hopes this helps.

Regards,
James

---------- FOLLOW-UP ----------

QUESTION: thanks again for the response James...

Last question for the day, I promise lol.  And this is really specific, so im gonna assume you probably dont know

I got the Madelaine Round Digital Hygrometer Thermometer (Adjustable Calibration)

Its this one: http://www.neptunecigar.com/pr/madelaine_adjustable_round_digital_hygrometer.asp

anyways, when I bought it, the person helping me with it turned it on to show it works but I think he forgot to put the instructions back in.   Apparently you can adjust the calibration, but the whole thing has one button.   And pushing that button changes it from celcius to farenheit.   

Would you by some fluke chance know how the calibration works?   I know its a long shot but thought i'd give it a try since you have yet to be stumped by any questions

thanks!

Answer
Hi Andrew,

For single button hygrometers, if you press and hold the button, the number in the display should start to change (like programming an alarm clock.)  Just press and hold the button until it reaches the correct number.  The best method to program this type of hygrometer is to salt-test it for 6 hours and if the display doesn't read 75% after 6 hours, press and hold the button (while still keeping the unit in the ziploc bag) until it reads 75%.  The hygrometer is now calibrated. :)

If this method doesn't work, trying resetting the unit by pulling and reinserting the battery before calibrating.

If this doesn't work, you may have to contact the store you bought the hygrometer from for the instructions or contact Madelaine's customer support from their website.

Hopes this helps!

James