Hydrometer help please

[stellaontap]

Hello

I have my hydrometer sitting in a test cylinder at 68 F and my gravity reading is 1.004. Does this mean that my hydrometer is out by 0.004 and if so do I just subract all of my gravity reading by that correction?

Thanks

Eric

 

[Meisterlowin]

In water, I assume? Also, is it distilled water or tap water. I think tap water has enough minerals and what not to affect the reading. It's best to use distilled water to calibrate the hydrometer. Other more knowledgeable folks should chime in shortly.

 

[Captain Damage]

Also, keep in mind that hydromerters are calibrated to a particular temperature. In the US it's usually 60F; I'm not sure if it'd be the same in Canada. The instruction sheet should tell you (if you still have it). At a temperature higher than the calibration temperature, you will read a gravity slightly lower than the "true" gravity, and vice versa. Your instruction sheet should have a correction table saying "if your temperature is X, add Y to your reading."

 

[DeafSmith]

Any air bubbles clinging to the hydrometer will affect the reading (causing it to read a higher gravity than it should). It is generally recommended to spin the hydrometer before taking a reading to get rid of any bubbles.

 

[stellaontap]

Thanks for the replies so far. My hydrometer is calibrated to 68 F (20 C) and I do have it sitting in tap water. I also spin the hydrometer to dislodge any air bubbles.

Eric

 

[bennyd]

I have also heard people on here saying that the paper inside the hydrometer moved up or down and affected their readings. Not sure how that would happen, but just my .02.

 

[jfr1111]

Take a few readings and act accordingly. My hydrometer is also calibrated at 68F but it reads a point higher. It can happen.

 

[rjwhite41]

Use distilled water to calibrate your hydrometer.