2x6 Boiling Depth & Batch Sizes

[tysonroggie]

I'm a bit frustrated, any advice appreciated and no need to hold back, let me know everything I'm doing wrong haha. I did a bit of a search so if I missed something in a previous thread feel free to redirect me. Thanks,
I am boiling on a sunrise spitfire 2x6 drop flue with a small squirrel cage fan for AUF. The syrup pan is 2x2 with one divider. I typically run around 1" to 1.25" in the front pan (hard to tell the level in the back pan as you'll see below). I also have an outside float box that seems to work pretty well.
I'll give a little rundown of how the process usually goes and then you all can chime in. We boil for a minimum of 3-4 hours before we make a batch of syrup (haven't used the RO yet this year due to small runs). First batch is usually around 2 gallons and then it is easily another 2-3 hours before we make another decent size batch around 1-2 gallons. The syrup taste is good and color is around medium. My main concern is that the the sap is boiling so hard in the back pan that it seems to "push" the sap to the rear of the pan (away from the syrup pan) and I can see the tops of the flues halfway back on both sides. I get nervous about burning the back pan (although it never seems to be an issue). This specifically wouldn't be a big deal except it doesn't allow sap to come around into the front pan and then I have to manually scoop sap into the front pan. I have tried adjusting the float to one notch deeper (floods the pan). I have tried holding the float down during draw off, and it may help some but I still have to move sap manually. It just feels like it should be easier and I fell like I'm always on the edge of burning syrup in the front pan because the sap isn't "coming around".
Another thing is that it is hard to tell the actual depth of the front pan because of the amount of bubbles, which then makes me nervous about burning syrup. Is it bad to add de-foamer to the front pan when drawing off? I have done it a couple of times and when I do I see that my thermometer is not even in the syrup (another indication that I'm not running deep enough?)
When we used to make syrup on my grandfathers old 4x14 it was pretty easy, Wait till 7deg. and then open the spicket. Once in a while we would have syrup in one of the other channels and scoop it over. This 2x6 just seems complicated. If i missed any pertinent details feel free to ask.
Thanks in advance for any input.

[PaulRenaud]

A couple of thoughts that might be of help. I never use defoamer, just a strainer to skim the foam off by hand. I do this in both pans.

Second, you can try using a short pipe as a means of seeing thru the steam and foam to look at how the boil is bubbling. Some rigs have set up what looks like a test tube outside of the evaporator to measure the depth - the tube is connected to the evaporator so it reads the same level. I just stick a spoon in to see the depth, but that only works when the boil is moderate.

This year, I kept my levels low in the evaporator (1 - 2 in) and in the finishing pan (3/4 - 1 in) and it made for a faster process than running with deeper levels. It does make it hard to manage the draw off, I was not able to maintain a continuous draw with those levels so shallow. In general, as long as their is a boil evenly in the evaporator and in the finishing pan, the syrup/sap should move in the right direction. You might want to double check that your pans are level. I discovered at the end of the season that my evaporator was not level and it explained why I had a low flow rate between the pans. Any liquid maintains its own level, but if the pipe between the two pans is on an angle, it will constrict the flow in the pipe.

Hope this helps.

[bill m]

Check the arch. Make sure it is dead on level side to side and front to back.

[wmick]

I'm going to guess that this is not your issue, being as you are using a store-bought rig... but I'll throw it out there anyway... just in case...
I have a homemade 2x6 and have pretty much identical issues that you are having...
Here is something I figured out at the very end of my run this year... but never had a chance to fix and re-try it yet... The line between my float box and my pan is a 3/4" hose with a 90 degree fitting in it .... I found that when it was boiling hot. AND I was drawing off a decent amount, that my 3/4" connection was restricting flow from the float-box to the pan and it was not replenishing quite fast enough to keep up with the evaporation and the draw-off at the same time. In hindsight, it makes sense... because there is basically zero head(gravity) pressure to promote flow.. I need a much larger orifice. I also had a similar problem with my line from my feed tank to my float box...

PS - Just a FYI - Last year I had a similar flow issue with pipe between my 2 pans... I up-sized it and eliminated that restriction..

[maple flats]

I just have one question, if you have a spitfire evaporator, 2x6 with a 2x2 front pan, why are you batch boiling? That rig or any rig with a divided syrup pan and a flue pan is designed to continuous flow. You add sap on one end, in the flue pan and draw off finished syrup from the syrup pan. Or are you just saying you draw a larger amount and finish it on a different heat source?
Back when I was in my early days of maple production, I attended a seminar given by Glen Goodrich. He said he makes a constant draw or at least tries to. He was running a large evaporator. He encouraged producers to try to match the draw to the evaporator. At that time I was boiling on a 2x6 on a rig that only go 25 gph evaporation on a good day. I tried to throttle my draw down and I was able to draw off finished syrup in quite long draws. Back then I just used 219.3 as my draw temperature. When I got to that on my thermometer near the draw off I opened the valve slightly. Then as the draw progressed I often had to tweak it slightly faster or slower as the draw temperature changed. I was able to get quite a few draws that ran 12-15 minutes and a few time almost 30 minutes before I had to close the draw off valve.
Later I got a 3x8 and on that I did the same, this time I often got 20-25 minute draws and a few times I got almost 60 minute draws but not quite.
It is a slow steady flow that matches the evaporator that is the key.
I now run an RO and a higher performance 3x8 and until 2017 I still ran the longest draws I could. Then for 2017 thru current, I started using an auto draw. I still regulate the flow rate by having a ball valve in line with the auto draw. However I do not get the real long draws, but I will often get draws that run 3-7 minutes, and in that time I might draw 2-8 gal. The 8 gal will be if I recently reversed the direction of flow, my first draw afer that is generally longer, the others will be in a 2-4 or 5 gal draws with 2-3 gal most common. Since it is controlled by a ball valve and is reset each time there is no constant.
I think you should try the same thing. Practice starting a draw and watch the thermometer, if the temperature climbs open the valve slightly more, if it drops too soon, close it some. It takes practice but you will get it in time.