Accurate temp gauge needed to test temp gauge to use hydrometer - help

[Stinky Bottom]

Hi,

As the silly title suggests - I am in a pickle and may be over thinking this but...

How on earth do I know the accurate temp from which to measure my sap when it is in the hydrometer cup when I know my thermometer is off (but by how much I do not know) and am trying to figure out how to determine exactly what the real temp is so I can complete the brix conversion.

I was thinking the boiling water calibration but that doesn't work because I would need to measure my elevation and barometric presure accurately, which just introduces more error.

Please help.

[wobbletop]

https://www.saptapapps.com/

That site will give you your current boiling point of water based on location, etc (as well as a bunch of other neat things). You can use that to calibrate your thermometer.

[Tweegs]

My way was a bit convoluted, but it worked.

I have a boat.
On the boat is a barometer…a good one, mechanical.
I don’t allow the barometer to winter on the boat, so it was home.

Took the barometer to the airport and parked as close to the run up area as I could.
(Very small airport)
Listened to the tower’s info over a radio.
Calibrated the barometer to the airport report (sea level compensated).
I know the airport elevation having previously looked it up online.
Drove immediately home.
Noted the difference in pressure between the airport and my shack.
Calculated exact altitude based on that difference.
(Or, you can forget all this nonsense if you can measure absolute pressure)
From the altitude and barometric pressure (SLC), you can calculate the boiling point of water.
Now you can calibrate your thermometer.
Whew!

On the cold side, use an ice water bath.

[Bricklayer]

Most hydrometers have the blue line for cold test. And the red line for hot 212 test. If you can grab the syrup from your drawoff valve right into the test cup and everything is kept warm including hyrdrometer. Then it should read at the 59 brix line on the hydrometer if given a couple seconds off the evaporator. Wait longer and temp goes down. And level changes.
I fought with this for a couple years. And bought a hydrotherm. They work great. They don't give instant readings but they are accurate I find if kept warm they take about 1 minute to give accurate reading. . Used that for a couple years and last year I got an autodraw. So I needed fast accurate density testing so I can set the temp for drawoff. So I bought a smoky lake Murphy compensation cup. I wish I had of got it years ago. Takes the guessing out of it. Works awesome and fast. But a hydrotherm or Quebec hydrotherm does the exact same thing and has temperature compensation built in. And it can also be used on room temperature or cold testing density.
I see your in canada. So any maple supplier should have hydrotherms in stock. They are like $35.

[Russell Lampron]

https://www.saptapapps.com/

That site will give you your current boiling point of water based on location, etc (as well as a bunch of other neat things). You can use that to calibrate your thermometer.

I got the saptapapp too and am having a lot of fun with it.

[Stinky Bottom]

Wow - lot of great replies. Thank you all.

Actually ended up using a little bit of info from everyone to figure it out. Finished the syrup 7.5 degrees above boiling point and test batch is perfect!

On an aside - am in need of some new equipment and have been debating buying a fancy VT approved hydrometer or one on those cheapy manual refractometers...

Any suggestions on what makes the best hydrometer?

I like the hydrotherm but my small operation and funky weather doesn't allow for me to consistently boil down large batches.

Best,

SB

[mellondome]

My way was a bit convoluted, but it worked.

I have a boat.
On the boat is a barometer…a good one, mechanical.
I don’t allow the barometer to winter on the boat, so it was home.

Took the barometer to the airport and parked as close to the run up area as I could.
(Very small airport)
Listened to the tower’s info over a radio.
Calibrated the barometer to the airport report (sea level compensated).
I know the airport elevation having previously looked it up online.
Drove immediately home.
Noted the difference in pressure between the airport and my shack.
Calculated exact altitude based on that difference.
(Or, you can forget all this nonsense if you can measure absolute pressure)
From the altitude and barometric pressure (SLC), you can calculate the boiling point of water.
Now you can calibrate your thermometer.
Whew!

On the cold side, use an ice water bath.

Most smart phones have a barometric pressure sensor built into them. You will just need an app to view the data.

[Sugarmaker]

Unless I am missing what your looking for here? Get a Murphy cup and Jim's hydrometer package. It is made to do what your asking, no muss no fuss!
Regards,
Chris

[Russell Lampron]

Wow - lot of great replies. Thank you all.

Actually ended up using a little bit of info from everyone to figure it out. Finished the syrup 7.5 degrees above boiling point and test batch is perfect!

On an aside - am in need of some new equipment and have been debating buying a fancy VT approved hydrometer or one on those cheapy manual refractometers...

Any suggestions on what makes the best hydrometer?

I like the hydrotherm but my small operation and funky weather doesn't allow for me to consistently boil down large batches.

Best,

SB

The hydrometer and a test cup if you don't have one already will be the most accurate way to measure density. The hydrometer reading is temperature dependent so you will need a way to measure that too. The Murphy cup and Accucup are two hydrometer cups that measure the temperature for you. The Murphy cup tells you what hydrometer reading you are looking for and the Accucup tells the temperature and you use a comparison chart with it. Some of the fancy maple hydrometers have a red line in the top of the glass so that you can see if the paper has slipped so you don't have to doubt the accuracy.