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Topic: humidifying beans, meters tested (8 msgs / 173 lines)
1) From: Ken Mary
Walmart has several different kinds of humidity/temperature monitors. I 
bought their Acurite model 00613 for $7.97. It is not adjustable. The
display size is huge, easily read from across the room. There are no buttons
except C/F, the display shows all values including max and min humidity
continuously. If necessary, it can be reset by pulling the AA battery. The
salt water RH reading was 76 and 77% in two tests, each lasting for about 36
hours. The handbook reference humidity for saturated salt water is 75.7% at
room temperature. So for use in a humidor, this unit would work fine as is.
Of course, other units of this model may read different and should be tested
before use.
A discontinued weather station was bought at the closeout price of $4.97
from Radio Shack, their catalog no 63-164. This unit uses a small button
cell battery. One test in the same setup showed that it read 9 or 10% low. I
disassembled it and found that the humidity reading can be recalibrated to a
higher value by connecting a resistor across the sensor terminals.
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2) From: John Despres
Ken,
I've been giving thought to stabilizing the humidity in my beans since I =
store them in a Michigan basement (read not so dry). Are you using yours =
to monitor room humidity or inside a container? I would imagine room =
humidity will give you the relative humidity of the beans, right? A room =
reading of, say 65% humidity, doesn't mean a bean moisture content of =
65%, or does it?
I need to go back and read up on all the cooler humidor posts. I don't =
know if that's what I want to do - There are space issues which may not =
allow a mega-quart cooler our cigar smoking friends here use.
John
Ken Mary wrote:
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-- =
John A C Despres
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616.437.9182
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JDs Coffee Provoked Ramblings =
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3) From: Paul Helbert
Good on you, Ken. What value did you find works for the ten per cent low
one? Does it still track humidity correctly with the resistor?
A couple of weeks ago I bought a bag full of the even cheaper little
Springfield Precisetemp units from WallyWorld. All read around 10% low but
took Sean's idea of just marking the unit's delta and adding it to the
reading. Humidity in the humidor is holding very steady at 59%. Odor is
amazing when I open it. Can't find the receipt to return the extra
hygrometers, though. Duh.
-- 
Paul Helbert
"The time has come, to talk of many things..."
-- The Walrus to the Carpenter
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4) From: Paul Helbert
John,
A couple of weeks ago, in the archives there were a number of links to cigar
pages for humidor construction and checking hygrometers.http://www.cigargroup.com/faq/#6.1My memory is not to be trusted, but I seem to remember that 60% relative
humidity results in coffee beans holding at about 11% moisture content. I'll
have to dig around a bit deeper to find the link on that one. Might have
been in one of Tom's articles on storage of greens.
-- 
Paul Helbert
"The time has come, to talk of many things..."
-- The Walrus to the Carpenter
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5) From: Paul Helbert
http://www.sweetmarias.com/green.coffee.issues.htmlThere were other I can't find. Ideal moisture content would be 12%. A steady
11% seems a pretty close compromise given the huge swings we get here and
the ease of getting to 60% RH with the propylene glycol.
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6) From: Paul Helbert
http://www.sweetmarias.com/green.coffee.issues.htmlThere were other I can't find. Ideal moisture content would be 12%. A steady
11% seems a pretty close compromise given the huge swings we get here and
the ease of getting to 60% RH with the propylene glycol.
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7) From: Ken Mary
I am setting up to test how fast green coffee will absorb moisture. If it 
gets close to equilibrium in a day or two then I may use a very small
container to store only a few roasts at a time, while keeping the rest in
less humid conditions.
There is a moisture chart here:http://www.mesoamerican.org/pdf/Cafe%20_Britt%20_Trial_II.PDFYour room humidity of 65% would produce a green coffee moisture of about
12.5%. Others like myself, especially in winter, have a house humidity of
about 25%. So coffee stored in breathable containers would quickly dry out.
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8) From: Ken Mary
I did not fix the radio shack meter yet. I am going to get a close enough 
resistor value by comparing it with the Acurite meter at room humidity, then
retest in the saltwater setup. I suspect that the linearity will be
affected. That weather station will be used for household humidity, so
extreme accuracy is not required.
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