hydrometer calibration

[lafite]

how do they calibrate hydrometers? I would think that someone would finally do away with the paper and have a permanent mark for cold and hot tests for maple producers.

[spencer11]

Not sure how they do it but the calibrate them at 60* I think the would take the volume of the hydrometer and then find out somehow how thick the syrup would need to be to float to where they say

[lafite]

sorry, I should have been more clear with my question. when they have seminars and open houses, they say they can re-calibrate your hydrometer. how would they do that?

[spencer11]

The only way I could see they could do that is to move the paper to the proper spot if it moved or add weight or remove weight to it somehow, not sure how they would do that without breaking the class though

[happy thoughts]

I may be wrong but I don't think they are actually recalibrating but checking accuracy against a known standard. There was a discussion about this earlier this year...

http://mapletrader.com/community/showthread.php?17881-Calibrating-Hydrometers&highlight=hydrometer+calibration

I would assume that like a thermometer that is *off* by a certain measure the same could be done when reading a hydrometer of known *offness*. Again, I may be wrong.

[jmayerl]

You can not calibrate a hydrometer. They are checked for acuracy in a known liquid.

[Rrwws]

This is a good question, I bought a hydrometer that was shipped from Michigan and when I used it, it made my syrup a little thicker than what you may see at the store. The flavor was unbelievably good, but thick which means with the little bit of sap I get less syrup. Im reading mine at the hot mark on the hydrometer for this thickness, so I think that if I call it good between the cold and hot mark I would be much better.

[lafite]

I realize you can't change or re-calibrate the hydrometer after it's made. if the paper slips, you are off. My question still stands, what do people use as an indicator when they get their hydrometer "checked"? if the paper moved once, I'm sure it will move again. Has anyone had their hydrometer checked at an open house?

[jmayerl]

I realize you can't change or re-calibrate the hydrometer after it's made. if the paper slips, you are off. My question still stands, what do people use as an indicator when they get their hydrometer "checked"? if the paper moved once, I'm sure it will move again. Has anyone had their hydrometer checked at an open house?

Like i said before. They are calibrated in a premixed liquid with a known density. Yes i have all 3 of mine checked every year. One was off .5 brix so i use that to draw, and a different one to finish. If you are looking for the exact name of the fluid or product i guess i dont know what that is

[happy thoughts]

If you are looking for the exact name of the fluid or product i guess i dont know what that is

If you read the thread I linked to earlier, Dr Tim said he believed it is a glycerin solution of known density.

[spencer11]

If you read the thread I linked to earlier, Dr Tim said he believed it is a glycerin solution of known density.
That would make sence since that's what they use in the grading kits

[lafite]

so once checked, and it's off, you use your "eye" based on where the paper mark is for the discrepancy?

It's not a question of getting a new one which are affordable enough. I was just curious.

[CBOYER]

In Québec, we buy a Density Standard, (1.322 )to calibrate to 66 brix at 20-25°c
http://www.unimat.ca/agricole/erabliere/evaporation/standard-de-densite-pour-sirop-d-erable.html

1 liter, is $24.98.