First time using drop flu

[Big Daddy's Sugar Shack]

Hey folks,

We had a small run here in NB last week so this weekend I fired up my brand new CDL 1.5 x 6 evaporator. I went from using a flat pan on a propane burner with 12 trees tapped to this rig with 90 trees tapped.

I have a few questions:

1) As I understand it, the natural process of the more dense molecules of the syrup push themselves in front of the less dense water molecules. After realizing that the gravity continuous flow into the evaporator wasn't working we started dumping sap in the back in the drop flu section from time to time. We would let it boil down and then add more. At the end of the day we finished the front pan right on the stove and when we drained the back flus we got more syrup from finishing that liquid than the stuff that was in the front. It didn't seem to push the finished syrup to the front of the rig like I thought it would, seems like a lot of waste to just discard the stuff in the back. Is this because of the lack of continuous flow and the adding sap at irregular times during the process?

2) What is the best way to deal with ice in my buckets and in my holding tank? It seems to take A lot of room and slows the boiling process by dropping the temperature significantly?

Thanks for any help.

Cheers,

[maple flats]

With a continuous flow evaporator, regardless of whether it is drop flue or raised flue, just keep maintaining the level where it should be, generally 1" deep once you get used to the rig, but many start with 1.5" for a boil or 2. It will take what seems like forever before you make your first draw, but don't keep "dumping" sap in, let it flow in by the float valve and keep adding wood when needed. In general if you have no extras on your rig, that will be to add wood every 7 minutes, by a timer. Have your wood seasoned and split it wrist sized. The draw off valve will be ready in due time to open.
You must realize how much concentrating will need to happen before you have syrup. On my 3x8 back before I had an RO I often boiled for 6-7 hours before I got any syrup, but after that it comes quite regularly. Your rig will likely be similar. Even now, running 8% concentrate into my evaporator it can take about 3-4 hrs before my first draw. During all of this time you are establishing the gradient (density progression as it nears the draw off)
After your last boil of the season, you will make lots of syrup just finishing off what is in the pans.
Have patience!
If your rig does not have a float box/valve, set up a method to adsd slowly using a small ball valve so that while you boil the depth in the pans remains constant.

[Big Daddy's Sugar Shack]

Thank you very much Dave! Excellent information I appreciate it very much.

[billyinvt]

Might not hurt to triple check that everything is perfectly level too.

[Sugarmaker]

As Dave said the float should allow sap to com in slowly. keep boiling! :)
We dont throw any sap away. and you should be able to make syrup on the evaporator not the stove.
Regards,
Chris

[Big Daddy's Sugar Shack]

Thanks Guys! I have checked the level and it is bang on. Where I wasn't using the float at all, I am guessing this is where my problem arose. I need to raise my holding tank so it will gravity feed into my float box. It wasn't working so I was dumping it in by the 5 gallon pail every 20 minutes or so. I will get this fixed for the next boil and see how it works better with continuous flow corrected.

[Big_Eddy]

Geoff - definitely get the float box working. The best thing you can do when running any continuous flow evaporator is to set a depth and maintain it as consistently as possible. Every increase or decrease in depth tends to move sap back and forth in the pans and will extend the time it takes to generate a good gradient. The ultimate goal is to have a steady stream of syrup coming out and a steady stream of 40x as much sap going in - but that's almost impossible to achieve on a small evaporator.

If you do have to feed by hand (bucket) what I do is pour into the float box. That limits how much I can add at once, and it adds it right at the inlet. It also slows down the entry of the cold sap, so there's not as much of a drop to the overall temperature in the flue pan. I was doing that on the weekend, as my feed lines kept freezing up (-16c) . I was feeding wood every 8 mins, sap every 4, about 1 gallon at a time. Same rate as you, but much more evenly.