Wacky Hydrometer

After thinking that I was starting to make some very weak potential wine I decided to check the calibration of my hydrometer. I discovered that in cool water it was readying .992 instead of the 1.0 it should have. Good, that means that wine that I thought was starting at 1.085, was actually closer to 1.093. But then again, it may also mean that my ending readings of .990 could be .998.

So, I bought a new hydrometer, and tested it. It read 1.0. I put the old one in the same water at it read about .993. Good, it is my hydrometer.

Then yesterday I check a batch of Eclipse Cab Sav I have in primary, and after four days it's at 1.022 on my new hydrometer. Well, let's just put in my old hydrometer. The darn thing reads 1.022. Back to the cool water test, both read .996. Now I'm just confused.

Not only did my new hydrometer change its calibration reading, but my old one did as well. To my thinking the only thing that could cause that are: 1. A serious change in the volume inside the hydrometer tubes by heat, cracks, atmoshperic pressure maybe. 2., the paper with the scale is moving inside the tube. I see no sign that scale has moved. The weather did drop maybe 15 degrees from one test to the next. Is that enough to cause the different readings in cool water? And if it is, I would expect it to be done uniformly by the two hydrometers, meaning that they will still show up as .008 different from each other, not to come to an agreement with each other.

Anyway, a wacky thing. Anyone else have an explanation or similar experiences? If nothing else, I'll fall back to my increasingly common position on most everything about life: Stop obsessing about the details, enjoy the journey and things will work out. Easier said than done for this engineer, but after 56 years I'm starting to learn. Now, back to figuring out why these things are not stable

Hydrometers are calibrated to operate at a certain temperature. If you look at the scale, you should be able to find a temperature written somewhere.

This could explain things as you did not take any temp readings.

JohnT said:

Hydrometers are calibrated to operate at a certain temperature. If you look at the scale, you should be able to find a temperature written somewhere.

This could explain things as you did not take any temp readings.

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The correction for temperature is only .003 over temperatures from 52.2 to 72.4. My initial test of the two together was with the same water sample within moments, so water temperature was irrelevant for the comparison as it was the difference that I noted. With a change in temp from cool water to warm must, the difference between the two should have been maintained, albeit both adjusted a tiny bit for the temperature difference. Instead, they then read the same SG.

Container of water @room temp, put both hydrometers in @same time (ID one of them), observe for @15 min, record any changes, get back to all of us, save up for another hydrometer!!!

G,
I ran your experiment. I did it in 60 degree water. New hydrometer read .998 and remained there for the 15. Old hydrometer started at .995 and stayed there. So now they seem stabilized, but I still wonder why the first reading of my new one was .007 different than the old one when I first tested it in the same water. Oh well, time to move on to bigger things.

Thanks,

Ted

AZMDTed said:

G,
I ran your experiment. I did it in 60 degree water. New hydrometer read .998 and remained there for the 15. Old hydrometer started at .995 and stayed there. So now they seem stabilized, but I still wonder why the first reading of my new one was .007 different than the old one when I first tested it in the same water. Oh well, time to move on to bigger things.

Thanks,

Ted

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Check your winery close. Think you mite have wine gremlins. Little buggers always messing with you. If I could give em away, they would go for free. Arne.

I'd make sure both hydrometers are calibrated for 60°. I think some are calibrated for higher, around 68° or so. You may have one for 60 and one for 68