Temperature drop during filtering

[Russell45]

Hoping somebody has actually measured how much syrup temperature drops during the filtering process. Somewhere I read it drops 10-15 degrees just from pouring it?

I filter 2-4 gallon batches through a standard orlon cone filter with 3 or 4 prefilters. I soak the assembled filters in an insulated SS coffee urn at boiling, remove the filters and blot most of the water out with towels, hang filters on an upside down tomato cage into a large SS pot. I pour into the filter at or close to final finish temperature, so maybe 217. Meanwhile I empty and unplug the coffee urn and put the insulated cover on it to keep it hot. Filtering goes smooth and reasonably fast right up to the end, so that works great. Transfer from the large pot to the warm (unplugged) coffee urn and bottle in new glass warmed in the oven to 175.

So most batches are perfectly clear, but some have a slight amount of suspended niter that settles out over time. Of course this annoys me beyond reason, go figure.

Am I filtering too hot? Filtering hot makes the process very smooth. With all the care in this, I've never actually measured, except towards the end of bottling, and I'm always above 180 at that point. Am I likely still above 200 when it hits the big filtering pot and making niter after filtering? Thoughts appreciated here. Have a great season!

[maple flats]

If still over 200 after filtering, it's possible you are still making niter, because you are likely still getting steam like moisture coming off the syrup. Niter is just minerals and such that don't remain in suspension. I suggest you lower the temp to maybe 205 before filtering and try it, anytime it looks like steam is coming off after you filter the syrup is marginally getting more dense and thus more niter precipitates out. maybe you will get better results if the after filtering temp is slightly below 180, and then very gently bring it up to 185 and hold it there.
You may at some point decide that a water jacketed bottler (WJ bottler) is in your future, that will help, but they aren't cheap.
Far different method and equipment, but I never get more niter forming when I bottle. I heat the syrup to 205-210, filter thru a filter press, then into my WJ bottler. There it is brought up to 185-187 and bottled at that temp. Having filtered at 205-210 I precipitated extra niter out which was filtered out. At that point I do need to bring the temp back up because even a 15 gal batch cooled enough thru a cold filter press that the temp is about 150-170 depending on the air temp in the sugarhouse. Slowly heating it to 185-187 in a WJ bottler does not create more, because it was filtered at over 200.