salt test with sea salt

[uvacom]

Originally Posted by Wharf Rat

The 75 F calibration point is based on pure sodium chloride. So, any impurity potentially changes it a bit. How much? I don't know. Perhaps the testing above will help.

See this thread for more tests on this.

Bob

http://www.clubstogie.com/vb/showthread.php?t=204696

Got that Bob, I have actually calibrated many a hygrometer. I used to cultivate fungi for fun.

What I'm saying is that I've found is that a salt slurry test depends heavily on there not being too much water in the slurry. Coarse salt has more space between particles that can store water, so maybe it's the coarseness of the sea salt that makes it less accurate. The impurities may or may not affect it as well, but as mentioned, table salt isn't pure either. It has iodine added.

[NakedYoga]

I am currently attempting to calibrate my new digital hygrometer (it's nothing special... a typical run-of-the-mill model I won for $15 on an eBay auction) with sea salt. I checked it for the first time today, after having let it rest for about 26 hours. The reading was 78% RH. It's +/- 5%, so I'm running the salt test again, probably for another 24 hours or so, to see if there is any change. The sea salt that I have in my kitchen is not the typical coarse, large grain sea salt; it pretty much looks exactly like the regular fine-grain table salt. We'll see how it goes.

[Wharf Rat]

Originally Posted by uvacom

Got that Bob, I have actually calibrated many a hygrometer. I used to cultivate fungi for fun.

What I'm saying is that I've found is that a salt slurry test depends heavily on there not being too much water in the slurry. Coarse salt has more space between particles that can store water, so maybe it's the coarseness of the sea salt that makes it less accurate. The impurities may or may not affect it as well, but as mentioned, table salt isn't pure either. It has iodine added.

Well, (nerd talk) the salt test works if the salt / water mixture is a "supersaturated solution". In other words, the water cannot absorb any more salt. It may be that folks need to stir better or wait longer for the mixture to stabilize.

Here's an idea. You could mix salt into boiling water until no more dissolved. Then, when it cooled to room temperature, it would guarantee a supersaturated solution.

Ever make rock candy?

Bob