Hydrometer Reading in Softened Water

[ithink2020]

So I had some question reading recently. I tested my Hydrometer with store-bought water. I thought it was distilled, but I'm not certain. It read 1.000.

This morning I was second-guessing another reading. I didn't have any distilled water, but I used our Tap water which purified with a water softener. The reading was .996. I'm guessing my test before was not with Distilled Water...

Should I add .004 to all my recent readings, since my hydrometer tested .996 in the softened water?

Thank you!

 

[sour_grapes]

I am not sure what is going on, but I can say that the difference between your two readings is certainly not due solely to distilled vs. softened water. The ions in softened water are in the tens of ppm range, and simply cannot account for a difference of 0.004. Furthermore, I would expected softened water to be denser than pure water. (I intentionally avoid asserting whether I think your distilled water is "pure" or not.)

There must be something else going on. Some will cite temperature differences, but in a reasonable range of temperatures, density only varies by ~0.001 to 0.002 or so. Was it the same hydrometer in both cases?

 

[ithink2020]

Yes, it was the same hydrometer. Now that you mention temperature, I think I was using cold water from the tap. Whereas before, I was using room-temp (~68 degrees) water from the store-bought jug.

 

[Rice_Guy]

I have 3 hydrometer, the triple scale is off from my mom’s double scale by .002 ,,, expect some difference tool to tool, and in the scheme of things for home wine making .002 doesn’t matter.
Paul has a good guess ,,, temperature

 

[sour_grapes]

Generally speaking, if you are always using the same hydrometer (and at the same temperature), density differences are significant. Absolute numbers, less so. (I acknowledge that you seem to know that based on your OP, but just stating for the record.)

 

[KCCam]

Yes, it was the same hydrometer. Now that you mention temperature, I think I was using cold water from the tap. Whereas before, I was using room-temp (~68 degrees) water from the store-bought jug.

Colder water would raise the SG if anything, not lower it, but as mentioned only by a point or 2 at the most.

 

[ithink2020]

Does anyone have a suggestion for an accurate hydrometer on Amazon?

 

[Scooter68]

For that little variation - I wouldn't waste the money replacing it. If you switched back and forth between hydrometers that might be an issue but as long as you are using the same hydrometer there shouldn't be an issue. You should be looking at relative differences. Just check the reading of the hydrometer with the type of water you plan on using. If that's tap water and the reading is .998 or .996 then you can easily adjust the wine must reading as you prepare it for that minor difference.

 

[KCCam]

Does anyone have a suggestion for an accurate hydrometer on Amazon?

I'm with Scooter68. For general wine-making it's not necessary. However I am a science kind-of-guy (with aging eyes), so I bought a couple of "precision" hydrometers on eBay. They are easier to read because the graduations are farther apart, especially floating in the primary. Each covers a 0.100 range so you need at least 2 of them: 0.900-1.000 and 1.000-1.100, and maybe a third one 1.100-1.200. One problem is that they are longer than a typical tri-scale hydrometer, so you need a taller testing cylinder. I always wanted to try calculating final ABV by boiling off the alcohol and using FermCalc's "Boiling (Spirit Indication) Calculator." But 0.001 difference in reading makes almost 1% difference in ABV.

 

[ithink2020]

Sounds like I putting too much thought it to this and just need to roll with it. Get a baseline, then take a final for an estimate.

Thanks, everyone!

Matt