Drawing off at 7 degrees

[deckers007]

Just a quick question on how people draw of syrup from there evaporators? i have a 2x6 evaporator with a syrup pan with 2 dividers ( 3 channels) last year was my first year and i was under the impression that once your thermometer was calibrated and i was happy with the density of the syrup using a hydrometer, i would draw of when the thermometer hit 7 and stop when it started to fall. doing this at the end of the day my syrup was to heavy and it needed to be thinned out with sweet. So i started drawing of until the thermometer dropped to 4 or 5 degrees, doing this i found my syrup at the end of a boil was almost perfect weight.

SO my question is, is this normal? or should i drop my thermometer a degree or two and only draw off until temperature starts to fall?

Thanks

[mol1jb]

I think part of it is where your thermometer is located. Mine is in my syrup pan about 10 inches from the draw off. So I start at the day drawing off at 7 into my hydrometer to confirm that my thermometer is right on for the day (or maybe a hair high or low depending on the weather). Then I start drawing off at 7 and then usually close off at 6 because my thermometer is so far away from the draw off. I think each rig is different and you will have to find what will work best for drawing syrup off.

[tcross]

syrup will be at different temps on different day and even within the same day it can change. yesterday I started making syrup at 8 then by the end of the day 8 hours later I was making it at 6.5. I sue the 7 as a guide and test with the hydrometer each time I draw!

[Urban Sugarmaker]

Also, depending on where your draw off box is, front or back of the pan, can have an impact. On my CDL 2x6 the draw off is in the front. Poor placement if you ask me because there's a lot more heat in the middle and back partition. I get syrup back there a lot before the front section until the gradient really picks up.

So, when I draw I get under-dense syrup for the temp followed by a spike in temp with over-dense. After a longer boil it all evens out.

[Russell Lampron]

I purposely draw my syrup off heavy and then thin it down at the end of the boil to get the density correct. It's easier to thin it down than it is to thicken it up. I only use the 7 as a reference.

[Daveg]

That's normal due to the gradient in the channels and the rate at which you draw off. In fact, at any given moment there is only a small percentage of the syrup that is at the perfect density. The trick is to dial-in the rate of draw-off combined with the feed rate. But you also have varying densities of sap entering the evaporator to skew all your calculations, as well as fluctuations in the barometer. Do you re-check density before bottling?

[wnybassman]

I purposely draw my syrup off heavy and then thin it down at the end of the boil to get the density correct. It's easier to thin it down than it is to thicken it up. I only use the 7 as a reference.

Exactly what I do. I usually start drawing at 9 and end at 6. Typically puts me about 2 brix over when I go to finish, so a little raw sap, permeate or sweet off the pan to thin it right.

[maple flats]

The 7 degrees is not exactly on, it is really 7.3. For that to be a good gauge you need to check the boiling temp of water with the same thermometer, or at least one that you have verified reads the same as your draw off thermometer. For testing the temp is not read until you have a full rolling boil, it is not as soon as you get a boil started.
I also used to draw a little heavy, but not a lot, then add sweet if I still had it, at the end of the season on final finishing I added permeate, before the RO I added distilled water, just a little at a time.
With my 2x6 I was always trying to do a constant draw, but it takes a rather fine stream and tiny adjustments to maintain the draw. I think the best I ever got without needing to close the valve was about 90 minutes, but 30-45 were far more common.
Now on an auto draw, I just verify the density about every half hour once I get it established for that day, it will and often does change thru the day, especially as the weather changes.

[wnybassman]

With my 2x6 I was always trying to do a constant draw, but it takes a rather fine stream and tiny adjustments to maintain the draw. I think the best I ever got without needing to close the valve was about 90 minutes, but 30-45 were far more common.


I got a 45 minute draw on my little 18x60 the other day, it was awesome. I thought I had the stream small enough to maintain constant, but it eventually dropped. But within 20 minutes I was drawing again.

[deckers007]

Thanks for all the great posts, from what i am seeing, everyone has there own little tricks to end up with a great finished product, i think i will just continue the way i am doing it and adjust 1 or two times during a boil.