Temperature for auto draw-off

[mayohill]

I'm wondering what temperature to set my auto draw-off? I did have it set at 219.5 but the syrup was a little light. It read only 55 Brix on my refractometer. is there a danger if burning the syrup with to high a draw-off temp?

[Bellehollow]

All depends on elevation and atmospheric conditions. Ours has been anywhere between 216 and 221
It may also change during the course of a boil. I use the saptapapp to get a starting temp and then adjust from there until right density. Remember to recheck during your boil!

[ecolbeck]

The boiling point of water (and syrup) changes with atmospheric pressure changes. You have to change your drawoff temperature accordingly. Use your hydrometer as the definitive measurement of when you've reached syrup. There's no reason syrup would burn if it goes beyond 219. In fact to make value added products like candy, cream and granulated sugar you have to bring it to temps well beyond 219.

[maple flats]

Mine has been anywhere between 216.6-222.0. The best tool I bought to find where to set my auto draw is a Marcland BABO meter. It gives you the instant barometric pressure and boiling temp of water, then just set the auto draw 7.3F higher. In fact, I found 7.4F gave me a more accurate density syrup. Contact Marcland Instraments.
After I got it I was surprised how much the air pressure changed many days. I use it to check about every hour.

[mayohill]

I want to thank everyone for the quick response. I'm going to check out the BABO meter rich away. Thanks Mapleflats.

[BCPP]

Should point out that while there is no danger of burning syrup by going over 219, you do need to be careful not to go too far over as the syrup becomes more viscous and slower to flow along the gradient. This, in turn, makes it lose more water and become even more viscous. A circle that will end with water content going to zero and burning sugar on the pan. All that takes place way beyond 219 and not usually an issue but something to be aware of!

[TapTapTap]

All depends on elevation and atmospheric conditions. Ours has been anywhere between 216 and 221
It may also change during the course of a boil. I use the saptapapp to get a starting temp and then adjust from there until right density. Remember to recheck during your boil!

I gave up on saptapapp before my free trial ended because I didn't agree with the parameters used in the temperature calculation. It uses the barometric pressure from a local NWS station and corrects it for my elevation. However, when I checked the boiling point of water based upon the actual barometric pressure measured by my weather station it was off by almost a degree! The app would be a lot more useful if it allowed the user to input barometric pressure instead of doing an extrapolation from current local weather stations.

I was however very impressed by the elevation estimate by the way. They nailed it at 939.03 above seal level although maybe their confidence in the significant digits is an over-exaggeration.

Ken

[DrTimPerkins]

We don't boil water or worry about the elevation or barometric pressure. We just set the drawoff temp to something near the last setting and start the evaporator. We test the first drawoff for density with a hydrometer (hot test) and adjust up or down from there. We use a modulating draw-off valve so typically there is syrup coming off the evaporator continuously . Doesn't matter if the first little bit is a tiny bit off when you're making 100+ gal/hr and you're blending several barrels of syrup together using fill bungs. It all seems to even out pretty well. We check the density every 15 min or so off the evaporator throughout the boil, and check it again in the draw tank with a hydrometer and Murphy Float before it goes through the filter press and into a barrel.

My grandfather would do the same years ago by just cracking open the drawoff valve and letting a small trickle come out pretty much continuously, checking with a hydrometer occasionally and watching the thermometer in the final partition.

[Bellehollow]

Regarding the app - I shouldve said I use it as a starting twmp, but always have to add 1.4 degrees and then use that as a start point. I did notice the station they pull off ofnis quite a bit lower in elevation which explains the difference.

[BSHC]

I highly recommend running an analogue thermometer along with the auto draw off. That's how I do it. If you ever have something strange happen it is good to have an old faithful thermometer. TBH we generally know where the old faithful thermometer needs to be and adjust the auto draw accordingly. Then sample and adjust after a few draws using a hydrometer.

[DrTimPerkins]

I highly recommend running an analogue thermometer along with the auto draw off.

And the batteries don't fail on it just at the wrong time.

Electronic temperature measuring devices can vary quite a bit. Thermistors tend to be fairly good (for decent units), but thermocouples can have very wide ranges (like +/- a couple of degrees). Regardless of whether you use an analog or digital device...the best approach is to always check with a calibrated hydrometer to be sure your syrup is actually syrup.