Temperature compensation for finished syrup refractometer

[rayjavu]

I have a new refractometer to check the Brix of finished syrup.
Can I test it right off the drawoff or do I haven to let it cool?
Do I have to compensate for temperature?
Where can I find a temperature compensation chart?
Thanks

[DrTimPerkins]

First a question....do you have a refractometer or a hydrometer? My comments below are for a refractometer, where you put a few drops of liquid in the instrument well and close the cover (if equipped) and then read the measurement either optically or on a digital readout. A hydrometer is a glass tube that is floated in the syrup.


Can I test it right off the drawoff or do I haven to let it cool?

The instrument and the syrup must be isothermal for the reading to be correct. Takes 1-2 minutes depending on how much sample and how big the instrument well is.


Do I have to compensate for temperature?

Depends upon the instrument. Some have ATC built-in, some don't. If it does, you still need to wait until the instrument and sample are the same temperature.


Where can I find a temperature compensation chart?

If needed, the instrument likely would include one.

[maple flats]

You can draw off, 2x and dump it back into the pan, then draw a 3rd time, then gently lower the hydrometer into the syrup. By the time it floats steady the temp will be 211 and that's the hot test line.
Suggestion before you use it, measure the distance to the top of the paper scale, and write it down, or put a permanent marker there on the glass. That will let you know if the paper ever moves. Another way is to put a permanent marker line at the red line, either way works. By the way, if you never drop the hydrometer in the test cup it won't likely ever move.
In the North American Maple Syrup Producer's Manual there is a conversion formula or chart. https://extensionpubs.osu.edu/north-american-maple-syrup-producers-manual-pdf/
Sorry, I read the question wrong, I answered for using a hydrometer.

[BCPP]

If you put the drops of syrup on and then look at the reading you will see it change as the temperature equilibrates. Most of the refracrometers I've seen only use a few drops of syrup so equilibration only takes maybe 30 seconds.

[Swingpure]

I take a little bit of syrup in a wooden spoon. I let the syrup sit in the spoon for about 20 seconds, then let one drop drip off the spoon, onto my ATC refractometer.


Now I have a question. Let’s just say for arguments sake the boiling point of syrup on this day is 218°. In the perfect world, would this equate to 66 Brix? And if that is the case, 66.9 Brix would be a higher temperature. Is there anything written down in the perfect world, how many degrees difference would 66 and 66.9 Brix be?.

[DrTimPerkins]

In the perfect world, would this equate to 66 Brix? And if that is the case, 66.9 Brix would be a higher temperature. Is there anything written down in the perfect world, how many degrees difference would 66 and 66.9 Brix be?.

The perfect world does not exist except perhaps in a lab. Differences in barometric pressure, elevation, dissolved constituent contents (we ASSUME pure sucrose solution...it is not truly), errors in temperature measurement, etc. can all affect the results. Boiling point elevation for syrup is generally 7.1 deg F at 66 Brix density (at sea level on a standard barometric pressure day), but can vary a good bit. In addition, the steepness of the curve at this point is very high and is not linear, so a tiny change in temperature makes a huge change in density.

Thus BPE is a decent guide to syrup density, but isn't failproof.