Trouble with Divided Pan-batching going on?

[ebliese]

We're in the third season of running our 2x4 divided pan from Smoky Lake. We have started to have what appears to be batching going on. That would be large draw-offs and long intervals between. For example, I boiled for two hours in the morning and got a nice draw. I do not believe I drew off any sweet when I shut down. In the evening, I boiled some more and was approaching a draw but the third channel of my pan became all foamy and wasn't tamed by defoamer. I have been using canola oil, usually two drops at a time, as my defoamer. I had a large foam-up in the third channel after I flooded the pan and it rose to an even higher level, also not tamed by canola oil, and I had to scoop some of the foam off.

So I'm not sure what's going on. I have not experienced this before. It was a very discouraging boil today. I'm going to drain the pan and see if it needs cleaning. Honestly, the season has felt kind of discouraging-one problem after another. On the bright side, we have solved the problems we have encountered.

Any thoughts or suggestions?

[DRoseum]

Check to see if the pan is level in all directions. I have had a couple situations where the pan became slightly un-level and it caused issues with getting a proper gradient and making syrup in a spot back in a channel away from the drawoff port.

[Z/MAN]

It sounds to me like your pan needs cleaning. I have that same problem at times, and it is always a buildup of niter on the pan. It starts right at the draw off port. Clean it with vinegar and you should be good. If you don't clean it, you risk burning the pan. In the future when it starts foaming under the same conditions time to shut down and clean. Pans are too expensive to gamble.

[ebliese]

Pan is level in both directions.

I've been thinking some today as I was working today at cleaning the pan (not a large amount of niter buildup). Three or four nights ago we had a big draw-off and the temperature kept climbing so we opened the valve more. We did not do anything with the float to compensate. We continued to draw off some nearup (as I read some call it) to thin the heavy syrup. This was our only draw that night. I wonder if this is where we went wrong? The next day my wife ran the pan solo (good for her!) and she raised the sap level some since she doesn't have as much experience at it. She experienced large foaming at the beginning and end in the third compartment. With the foam at the end, she added some ice and scooped some foam to another compartment. After this, I ran the pan the next boil, lowered the level, and was getting close to a draw but was experiencing the foaming in the third compartment so I preemptively drew off hoping this would solve the problem. It didn't and I continued to get large amounts of foam untamed by defoamer.

So I find myself with a cleaned pan, sap back in it and sitting (and mixing), and maybe two gallons of sweet from the preemptive draw. My plan when boiling next is to start the fire, add the sweet slowly, and hope the gradient comes back and the foam doesn't.

[LMP Maple]

I would also say this is sugar sand. Anytime I have experienced foaming like that it is always related to sugar sand. That has been my experience.

[82cabby]

Ebliese- what depth are you running your pan at? Any chance it’s too shallow?
Also it sounds like you are occasionally making big draw offs. I have good luck drawing slowly (almost a trickle) very often and maintaining the gradient as much as possible.
If it helps, I’m running a 24x48 divided pan at 2” depth and draw off at about 220 degrees till it drops to 219. A commercial foam reducer works great for me.

[ebliese]

We run somewhere between 1.5" and 2" I would say. I had read on another post about a guy with a Smoky Lake Drop Flue pan set having a similar problem and he raised his depth to 1.75" from 1" or 1.25" and his problem was solved.

[ecp]

This question is going to sounds out of left field and I'll try to explain what I know about it. Have you cleared the bottom of your pan (the underside)? if you get a chance to flip it over check and see if there is a black soot built up in the same location you are having your foaming issue. If there is I have found dawn power wash cuts it decently (again the underside no sap/syrup comes into contact here). The thought is that this Cabon (black soot) build up actually attracts heat and absorbs it causing a "hot spot". There is a push going around my area to get larger producers even with oil to check this and see what cleaning it does. I can tell you it completely changes the boil but that's all I know.

[ebliese]

ECP, I understand what you mean. Since I pulled the pan off to clean, I power washed the underside of the pan with water. There was a lot of soot on there from this year which washed off easily. I still had hardened soot on there from last year and that also is now gone.

[ecp]

What are you using for a defoamer?

[ecolbeck]

This question is going to sounds out of left field and I'll try to explain what I know about it. Have you cleared the bottom of your pan (the underside)? if you get a chance to flip it over check and see if there is a black soot built up in the same location you are having your foaming issue. If there is I have found dawn power wash cuts it decently (again the underside no sap/syrup comes into contact here). The thought is that this Cabon (black soot) build up actually attracts heat and absorbs it causing a "hot spot". There is a push going around my area to get larger producers even with oil to check this and see what cleaning it does. I can tell you it completely changes the boil but that's all I know.

Interesting. Can you cite a source for this claim? It’s my understanding that carbon layers are actually insulating and reduce heat transfer. This is why people brush and clean the bottom of their pans. If soot buildup increased heat transfer then we would be doing everything possible to attract soot onto the pans.

[berkshires]

Pan is level in both directions.

I've been thinking some today as I was working today at cleaning the pan (not a large amount of niter buildup). Three or four nights ago we had a big draw-off and the temperature kept climbing so we opened the valve more. We did not do anything with the float to compensate. We continued to draw off some nearup (as I read some call it) to thin the heavy syrup. This was our only draw that night. I wonder if this is where we went wrong? The next day my wife ran the pan solo (good for her!) and she raised the sap level some since she doesn't have as much experience at it. She experienced large foaming at the beginning and end in the third compartment. With the foam at the end, she added some ice and scooped some foam to another compartment. After this, I ran the pan the next boil, lowered the level, and was getting close to a draw but was experiencing the foaming in the third compartment so I preemptively drew off hoping this would solve the problem. It didn't and I continued to get large amounts of foam untamed by defoamer.

So I find myself with a cleaned pan, sap back in it and sitting (and mixing), and maybe two gallons of sweet from the preemptive draw. My plan when boiling next is to start the fire, add the sweet slowly, and hope the gradient comes back and the foam doesn't.

I'd bet dollars to donuts that your problem does not return. I have a strong suspicion that the big change to levels in the pan wound up with you making syrup in the third channel instead of the fourth (assuming it's a four-channel pan). The reason I say this won't happen again is that once you start up, as you add your nearup to the last channel and your fresh sap the the first channel, you should get a proper gradient back.

I'm fairly sure that on pans where you don't block the channels, so everything can mix between boils, what you're describing is a common occurrence. I think this happens because when you start up again, and you have an even amount of sugar in all the channels, you can get a harder boil in the middle of the pan rather than the outside of it, which causes the second-to-last channel to start to make syrup before the last channel does. This is why I always try to draw off some sweet from the last channel when I'm finishing a boil and add it back in to the last channel as I'm starting up the next boil.

I've read other more experience folks here talk about what to do when this happens. Maybe one of them can speak to it. It involves moving sap between channels. Something I might need to do on my next boil, since I forgot to draw off sweet before I shut down on my last boil, LOL!

Good luck, and let us know what happens!

GO

[craigwade2005]

Any chance you are running a RO?
We found with 10% sap in our 2x3 Mason that we had to start fresh every morning. There was simply not enough flow in to produce a good gradient before the first draw and we ended up with burnt syrup in the 3rd bay(out of 4).
Ended up drawing off the cooled sweet in the morning, cleaning the pan and just re adding the sweet into the prewarmer as the day went on. Solved all of our issues.

[Swingpure]

Thank you for this topic, I have learnt a lot reading it. It also is a little scary, but it is good to know what to look for and how to fix some of the problems.

I think I will draw off some sweet at the end of the boil. The shape of the openings in my divided pans are not easy to block, if I want to do that, I will have to be creative.

22949

[maple flats]

What I used to do if I was making syrup in my 3rd section (out of 4) is I would start a slow draw at my draw off, it often went long, and it went much higher at draw off than normal, at which time I opened the draw off more, all this time my incoming float was bringing more say in from my flues pan which was boiling RO concentrate. As soon as the temperature got down to about 223, I slowed the draw, it took little time to again get to draw temp less .1 or .2F and I went back to normal operations. I then checked the density of the contents of my draw off tank, if too dense I drew more and mixed it in, until I had proper density (that was often the case). If too light I waited until my draw off temp was about syrup+.3 or .4F. In each case, syrup temp was always water boil + 7F. I could always get the density corrected, but I had a 25+ gal draw off tank.

[berkshires]

What I used to do if I was making syrup in my 3rd section (out of 4) is I would start a slow draw at my draw off, it often went long, and it went much higher at draw off than normal, at which time I opened the draw off more, all this time my incoming float was bringing more say in from my flues pan which was boiling RO concentrate. As soon as the temperature got down to about 223, I slowed the draw, it took little time to again get to draw temp less .1 or .2F and I went back to normal operations. I then checked the density of the contents of my draw off tank, if too dense I drew more and mixed it in, until I had proper density (that was often the case). If too light I waited until my draw off temp was about syrup+.3 or .4F. In each case, syrup temp was always water boil + 7F. I could always get the density corrected, but I had a 25+ gal draw off tank.

You must have had nerves of steel. That sounds scary as hell. How big an evaporator were you operating? Not sure if that would work as well on a little 2x3 or 2x4. I would be scared to death of burning the whole thing. Especially since I don't have a float, and i'd be trying to match the outgoing and incoming manually.

GO

[ebliese]

ECP, we are using canola oil as a defoamer. This is the first year using it. Last year we used safflower oil.

Berkshires, it is a three channel pan.

Craigwade2005, yes, we are ROing-RB25 from The RO Bucket. We collect in 30 gallon barrels. Usually the first barrel is ROed (one pass) to the head tank. This first barrel is a higher sugar content from my yard trees so theoretically I wind up with, say, 6% sap in the head tank. While that is boiling the other barrels are all concentrating into one or two barrels. The concentrated sap in the barrels is then ROed (second pass) into the head tank. However, last night I let the head tank get to 5 gallons and then started my fire. Since the sap was warmer (about 50*F) the RO was concentrating better. I wound up staying at 5 gallons in the head tank the entire boil-evaporation rate was matching the RO rate. Usually the RO processes faster than the evaporator does.

Some observations from last night's boil.
It went way better-no excessive foam uncontrolled by defoamer (canola oil). We did still have some foam ups but they were controllable. We are noticing the third channel (the draw-off channel) is still almost a solid foam (or bubbles almost to syrup). We did some hydrometer tests at various points in the channel. One test showed the front was 57 Brix, the middle 55 Brix, and the back was 55 Brix. Another test showed 55 Brix at the front and 50 Brix in the back. So we do have a gradient in the channel, but it maybe is a small gradient? I wonder if I need to take Craigwade2005's method of starting with raw sap (or slightly concentrated-4%) in the head tank to help reestablish the gradient along with adding some sweet back in.

We had three draw-offs last night, two longer. One was 11 minutes. The draw-offs felt much better, like we were in more control of them (and the evaporator).

The sap seemed to boil much more aggressively after cleaning off the underside.

[ecp]

Glad to hear things are looking better. Early season and late season can be a foamy time. Canola oil is probably the worst defoamer out there (if it's not the worst it's the second worst). Depending on if you sell bulk or retail or give to family I would recommend changing your defoamer. Albeit I use canola oil but only because of the organic certification. If I was not in that game, I would go with the synthetic defoamer in a heartbeat, and if I was a back yarder giving it all to family I would go back to using a chunk of salted port fat on a string.

[ebliese]

I would say deodorized sunflower oil is the worst defoamer. We had to use it in a pinch at the beginning of this season and we found it didn't work well at all. Canola works better (so I guess that jives with what you said about canola oil being the second-worst). Safflower oil might be the best of the three cooking oils but I have only been sugaring for four years. My wife and I were both wondering if maybe we should get some commercial defoamer.

[Openwater]

What do you mean by "commercial" or "synthetic" defoamer? Are they just different kinds of oils? Or something different?

[ecp]

When I talk about "commercial" or "synthetic defoamer" I'm talking about what you would buy from a vendor like CDL that is non-organic. There are a few types out there some are powder, and some are liquid. They all have a list of ingredients on them that I have not memorized but it's not oil.

Butter works well too or really any dairy product but if you sell to a packer that is a big no no. Really any fat would work, but due to allergens and flavor profiles that's why the "big guys" have landed on Canola oil which is good for the industry but when I downsize to a retirement sugar place I'm going back to salted pork fat. I am glad the packers are pushing flavor and not using dairy (it's one or the big 7 allergens) but when i no longer sell to them I'm done with canola oil.