Absolute Humidity

kuzi16kuzi16 Posts: 14,616 ✭✭✭✭
Lasabar:
So do I take any solice in the "Relative Humidity"? or is that if it's 60Degrees or 80Degrees it should always be at 67%Rh???
we always talk about RH.
"whats your RH?"
"i keep my humi at 65% RH"

Wikipedia states:
The relative humidity of an air-water mixture is defined as the ratio of the partial pressure of water vapor in the mixture to the saturated vapor pressure of water at a prescribed temperature.


uhh... what? Pressure? do i now need a barometer in my humidor?
no. no you dont. vapor pressure is basicly the the pressure that water feels to vaporise.

damn science getting in the way of a good time...instead of dealing with the vapor pressure and all that we can estimate RH if we know temp and the dew point temp. ...long story very short when the temp changes the dewpoint does as well. the lower the temp the lower the dew point the less water in the air. bla bla bla science bla bla bla...

when we say "RH" we actually mean "RH at 70* fahrenheit" since 70/70 is accepted for some reason in the cigar world we all say RH on the assumption that the humi is at 70*f.

the reality is we are all talking about "AH"
if im not mistaken our hygrometers are reading Abolute Humidity. thats easy to understand. Absolute humidity is the mass of water vapor per cubic meter of air.
so as long as you keep your humidor at bout 70*f you can speak in RH if not....
personally i plan in staying with RH. its what im used to.

one more fear. If you have your humidor at 70% AH and the temp sudenly drops outside your humidor to about 35* would that cause some of the water to condense on the inside walls of the humidor?


ok... i hope i didnt botch that up too bad. Im not a meterologest, im a cook.
...who smokes cigars.
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Comments

  • dutyjedutyje Posts: 2,263
    Only one correction Kuzi.. dew point does not change with temperature. The "humidity" you see in weather forecasts is a relative humidity. Relative humidity changes based on air temperature, but the dew point (the temperature at which 100% humidity is reached) remains fixed.

    I have no idea whether our hygrometers are engineered to measure humidity or relative humidity. I have noticed, however, that the humidity reading in a sealed container will change based on the temperature of the container (i.e. moving from the hottest part of my house to the coldest part of my house). As a side note, things like the salt test create an environment of 75% relative humidity, so the temperature would be irrelevant. All this points to the hygrometers reading relative humidity.
  • madurofanmadurofan Posts: 6,152
    Um my humis sit in the wine fridge at 65* so when my hygro reads 70%/65* ... is that 70%RH at 70* or 70%RH at 65* or is the temp irrelevant?
  • dutyjedutyje Posts: 2,263
    I think we've crossed well beyond the talk-out-your-ass threshold here.

    I am not a scientist, but here is what I believe:
    1. Our hygrometers measure relative humidity
    2. Relative humidity will rise as temperature drops and/or pressure rises
    3. The difference between relative and absolute humidity is largely irrelevant for our application

    There is a term in the rock climbing world called "gumby" which refers to someone who speaks as if they are relaying fact when they are just making stuff up or taking their best guess. Gumbies are notoriously dangerous, because they are usually found "leading" groups of new climbers. One such gumby recently handed a panicked girl a knife so that she could cut her rope while she was dangling helpless 300+ feet above the ground at the Gunks in NY. Another gumby works at our local climbing gym, and was explaining why we measure the strength of our climbing gear in kilonewtons. He told the students in his class that "one kilonewton is a 100-lb person falling 10 feet". The ratio of incorrect statements to words in that sentence is mind-boggling.

    The point I'm trying to make here is that we run the risk of muddling things up by talking well beyond our own areas of expertise.
  • madurofanmadurofan Posts: 6,152
    Good points duty! Urbi would be in his area of expertise here though so lets wait for him.
  • dutyjedutyje Posts: 2,263
    We gonna pester him on his birthday?
  • madurofanmadurofan Posts: 6,152
    Oh yea its his birthday, mines a week from today :). ANyone have his phone number? we should fill his vm inbox.
  • kuzi16kuzi16 Posts: 14,616 ✭✭✭✭
    dutyje:
    The point I'm trying to make here is that we run the risk of muddling things up by talking well beyond our own areas of expertise.
    at least i understood that i dont know what im talking about. i even stated it. i knew full well that i may have botched that up. what i DO know is that RH and AH are different. RH depends on more than one factor. AH depends on exactly two factors.
  • madurofanmadurofan Posts: 6,152
    The worst kind of people are the ones with Dunno Squared. They Dunno that they Dunno.
  • dutyjedutyje Posts: 2,263
    We're all just "dunno"... I still have fun talking about this stuff even when I'm outside my area of expertise. If it's something that lends itself to an experiment, I also enjoy conducting the experiments.

    On a related note, I have a couple tupperdors that I keep with very low-charge 65% beads. Here's something I've been unable to explain, and maybe we can all theorize as to why that is. When I have the tupperdors completely sealed, the rH rises to alarming levels. I've been keeping the lid on the container without pressing it closed, and the rH has stuck perfectly at 66% for the last six weeks. If I open the tupperdor to take some sticks out, the rH gets back up to a perfect 66% within 20 minutes and just stays there (as long as I don't seal the container).

    Why does the humidity continue to rise with beads in a sealed tupperdor? WTF?
  • madurofanmadurofan Posts: 6,152
    This could be the problem I'm having with my tupperdor. I'm going to try not sealing the lid.
  • kuzi16kuzi16 Posts: 14,616 ✭✭✭✭
    decharge more of your beads. are your beads 65% or 70%? i had to ask. also, how long have those sticks been in there? whats the temp and where is it located?
  • Smoke=FireSmoke=Fire Posts: 692 ✭✭
    I am just going to go smoke my cigars now before they have a chance to be fouled up by my not maintaining RH...or AH, but wait, the temperature is not stable at 70 degrees, it is warm, I may have beetles...or mold! Oh no! What can I ...

    *lights cigar* Ahhh...*smiles*

    What was I worried about again? ;)
  • madurofanmadurofan Posts: 6,152
    Smoke=Fire:
    I am just going to go smoke my cigars now before they have a chance to be fouled up by my not maintaining RH...or AH, but wait, the temperature is not stable at 70 degrees, it is warm, I may have beetles...or mold! Oh no! What can I ...

    *lights cigar* Ahhh...*smiles*

    What was I worried about again? ;)
    If you're worried about it smoke you could send your collection to me I'll make sure they are stored at a perfect 65* :)
  • urbinourbino Posts: 4,517
    ISTM duty has pretty well covered the issue, here. One question left dangling:
    kuzi16:
    If you have your humidor at 70% AH and the temp sudenly drops outside your humidor to about 35* would that cause some of the water to condense on the inside walls of the humidor?
    Yes. Unless your cigars were able to rapidly absorb all the excess moisture. Either way, bad ju-ju.
  • Smoke=FireSmoke=Fire Posts: 692 ✭✭
    madurofan:
    Smoke=Fire:
    I am just going to go smoke my cigars now before they have a chance to be fouled up by my not maintaining RH...or AH, but wait, the temperature is not stable at 70 degrees, it is warm, I may have beetles...or mold! Oh no! What can I ...

    *lights cigar* Ahhh...*smiles*

    What was I worried about again? ;)
    If you're worried about it smoke you could send your collection to me I'll make sure they are stored at a perfect 65* :)
    You, Sir, are a humanitarian ;)
  • urbinourbino Posts: 4,517
    Yeah, that's gotta be a pretty nice collection, now that you got that big order in.
  • LasabarLasabar Posts: 4,473 ✭✭✭
    So how come on my digita Hygro when the temp drops so does the Humidity? is it bad or sumpin'? It tells me both Temp and Humidity
  • urbinourbino Posts: 4,517
    If our hygros are reading RH, what you're seeing makes no sense to me, Lassy. It makes perfect sense as a matter of absolute humidity.
  • madurofanmadurofan Posts: 6,152
    Correct me if I'm wrong here urbi but this is my opinion. Lasy the reason you are seeing this drop in humi as well as temp is this. Your apartment is sitting stagnent in summer months, this allows the humidity to build up. Then when you fire up that window unit its sucking the humid air out of the room and pushing cooler AND less humid air back in. My slight understanding of how AC works leads me to believe a lot of the humidity in the air would be lost in the process.
  • kuzi16kuzi16 Posts: 14,616 ✭✭✭✭
    sounds logical to me.
  • LasabarLasabar Posts: 4,473 ✭✭✭
    madurofan:
    Correct me if I'm wrong here urbi but this is my opinion. Lasy the reason you are seeing this drop in humi as well as temp is this. Your apartment is sitting stagnent in summer months, this allows the humidity to build up. Then when you fire up that window unit its sucking the humid air out of the room and pushing cooler AND less humid air back in. My slight understanding of how AC works leads me to believe a lot of the humidity in the air would be lost in the process.

    You sir, just replaced "Bill Nye" as my source of science!
  • madurofanmadurofan Posts: 6,152
    Lasabar:
    madurofan:
    Correct me if I'm wrong here urbi but this is my opinion. Lasy the reason you are seeing this drop in humi as well as temp is this. Your apartment is sitting stagnent in summer months, this allows the humidity to build up. Then when you fire up that window unit its sucking the humid air out of the room and pushing cooler AND less humid air back in. My slight understanding of how AC works leads me to believe a lot of the humidity in the air would be lost in the process.

    You sir, just replaced "Bill Nye" as my source of science!
    Scary ...
  • Smoke=FireSmoke=Fire Posts: 692 ✭✭
    urbino:
    Yeah, that's gotta be a pretty nice collection, now that you got that big order in.
    Oh yes ;) The Gurkha humidor is a nice one that is being seasoned, the coolerdor is working out nicely, my C.Com humidor is full of the Brazilians, and my good humi is chocked full once more. Life is good :D
  • urbinourbino Posts: 4,517
    madurofan:
    Correct me if I'm wrong here urbi but this is my opinion. Lasy the reason you are seeing this drop in humi as well as temp is this. Your apartment is sitting stagnent in summer months, this allows the humidity to build up. Then when you fire up that window unit its sucking the humid air out of the room and pushing cooler AND less humid air back in. My slight understanding of how AC works leads me to believe a lot of the humidity in the air would be lost in the process.
    That is correct. That was actually the main point of air conditioning, back in the day -- to dehumidify the air. The thing is, while that would explain the temp drop on Lassy's hygro, it doesn't explain the RH drop, IF the hygro is in fact measuring RELATIVE humidity.

    (Disclaimer: I'm no expert on the terminology of "RH", etc. I know the basic physics of cool air holding less moisture than warm air, and I've read the definition of RH. If I'm misunderstanding the latter, I could be completely wrong about Lassy's experience.)
  • madurofanmadurofan Posts: 6,152
    Good point urbs ... if its relative it shouldn't be affected. Unless its sucking more humidity out than just what is relative. If that makes sense.
  • urbinourbino Posts: 4,517
    True, but then you would expect his humidification device to compensate. Maybe the drop in temp is too fast for it to keep up, but it should return to normal at some point -- reasonably quickly, one would hope.
  • madurofanmadurofan Posts: 6,152
    Well unless its passive. What is your humidification lassy?
  • LasabarLasabar Posts: 4,473 ✭✭✭
    madurofan:
    Well unless its passive. What is your humidification lassy?
    Got me two large discs of "Heartfelt Humidity Beads" at 70% but they are a little under-filled for i want to gain 67%
  • madurofanmadurofan Posts: 6,152
    Well those bads are passive but they should recover fairly quick.
  • dutyjedutyje Posts: 2,263
    Lasabar:
    madurofan:
    Well unless its passive. What is your humidification lassy?
    Got me two large discs of "Heartfelt Humidity Beads" at 70% but they are a little under-filled for i want to gain 67%
    when you say "under-filled" -- you mean some of the beads are white? or do you mean it's not filled all the way up to the top with distilled water? The latter will keep you running high for qutie a while.
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