Steam table pans burning the foam on the side of the pans...yikes

[maplerookie]

Boiled for the first time this year got 3 steam table pans on a block arch. Initial boiling went well but as i got down to lower levels towards the end the foam started blackening on the sides of my pans. The syrup came out quite dark. it doesn't taste or smell burnt , but I think I was lucky as far as that goes. I boiled hard all the while. any Ideas too keep the burn away. I don't have a stack temp guage but I know I was burning hot. but If I let up on the fire I would quickly loose the boil.

[Birddog]

I kept skimming off the foam to keep off the sides of the pan. That seemed to help but not eliminate it completely.


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[eustis22]

that's normal....it' splashed up from the bubbles. it's ok. it might darken your syrup but that's all. keep skimming and use a defoamer on occasion (I use 1/2 n 1/2). just keep the sap level below the edge of sugar build up. You'll be fine.

[RileySugarbush]

it's normal. Don't worry about it, it will filter out.

Enjoy your delicious homemade syrup!

[maplerookie]

Thanks guys for the reassurance...I will probably just go with it then. A friend says I should get my pans up so only the bottom 3/4 inches is getting the flame I am thinking about that also. steel angle brackets cutting and welding. too bad I don't weld and have a angle grinder. jeeesh! Eustis 22 what do you mean by 1/2 and 1/2 re the defoamer?

[MapleLady]

I boil on a block arch with 3 steam table pans set into the arch. The foam on top of the boiling sap does tend to burn around the edges of the pan. Just keep skimming the foam as best you can. Some folks use a bit of half and half (the creamer by the tsp.) or a tiny dab of butter to keep the foam down. I prefer not to add that, if I can avoid it. Hope this helps.

[happy thoughts]

I use a couple of drops of canola oil. You can use cream or butter but there is the chance it may go rancid in long storage and also the potential for food allergies for those who can't tolerate dairy products.

I also clean the insides of my steam pans between boils so each batch starts fresh.

[DoubleBrookMaple]

Bill...
My experience.
My first two batches of five were darker Grade B (I have a grading kit, and they were lighter than the grade B, but darker than dark amber.
Last year I had 3 steam pans and made 6 gal. Boil rate with preheater was 8 gph. I used two 6 inch, and a 4 inch up front. I used siphon method into front finishing pan, and ladle as well. I used defoamer rarely, only a few times when foam went wild. The pan were kept as full as possible to keep sides covered, lots of stiring, and near end I transfered all the syrup into the front 4 inch deep pan for finishing. My syrup was of good flavor I am told. I did get a lot of blackening on the sides of the pans, and they were hell to clean inside and out between batches.
Here is what I got.
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[Maplesapper]

Boiled for the first time this year got 3 steam table pans on a block arch. Initial boiling went well but as i got down to lower levels towards the end the foam started blackening on the sides of my pans. The syrup came out quite dark. it doesn't taste or smell burnt , but I think I was lucky as far as that goes. I boiled hard all the while. any Ideas too keep the burn away. I don't have a stack temp guage but I know I was burning hot. but If I let up on the fire I would quickly loose the boil.

Steam pans extend too far down into the fire, so the flames will touch the side of the pans which is dry and scortch.
Almost like running a half empty flue pan.
Try maintaining high levels in all pans. Then as you run out of sap and all levels get low, pour one pan into the other, and pitch snow in the empty pan, and place back on the fire- great way to sterilize lids anyways.
Once the level starts to drop in the last pans, go easy on the fire.
Batch boil will always be darker but you can lessen the impact.

[Quagmire33]

I agree. Keeping my pans as full as possible reduced the scorching and when I got close to the end bringing it all into one pan helped. But once I was down into one pan and the level got down into the flames I would let the fire die down, takes longer to evaporate, but reduced the intense heat on the sides of the pan. My 6" steam pans were set full depth into the 55 gallon drum fire box. I never got really dark syrup, just had to go easy towards the end.

[maplerookie]

Eric mine looks just like yours does and the taste is devine.Thanks for all the reassurance ladies and gents. I have lots of fun sugaring. I got 1 qt jar and a pint jar started at 9 am and was done and cleaned up by 4 pm. so I am not sure how many gallons per hour I got. I figure not quite 30 gallons of sap to start. I too do the ladle from front to back kept my pans very full for as long as I could. at the end I had about 1 inch in the final pan when I hit 214 degrees (water was boiling at 208 that day) I finished in the house on the stove. filtered as it came off the arch and filtered before putting into jars. My daughter helped she manned the screen to take off the foam. Now everything is frozen again...looks like for the next week. So we wait.

[CampHamp]

When I boiled on steam pans, I sat the pans up and put sections of hollow rectangular steel between the pans so the flames wouldn't burn the foam line. In this photo, you can see the steel sections. I also poured sand around edges to keep the smoke from filling up the small plastic greenhouse I was working in.

8898

I also made some siphons out of copper pipe (not installed in this photo) after getting tired of ladling. You can read about how to make them somewhere in this forum - it's not obvious how to do it otherwise.

[eustis22]

As a Red Sox/Pats fan, can I just say there is something very wrong with reading "Boston, NY"?

[lyford]

Hey Maple Rookie I'm not too far from you over in Hamburg, NY. Nice to see someone in the area has already got the season rolling. I put out two test buckets during the last thaw but only ended up with just over a half gallon between the two. Are you tapping sugars or reds? Looking forward to the next thaw, have a great season!

[maplerookie]

Hey Maple Rookie I'm not too far from you over in Hamburg, NY. Nice to see someone in the area has already got the season rolling. I put out two test buckets during the last thaw but only ended up with just over a half gallon between the two. Are you tapping sugars or reds? Looking forward to the next thaw, have a great season! Hi Lyford. tapping sugars ,reds and silvers. I am over at the confluence of feddick and zenner up on the hill. I have 19 buckets out and managed to get about 25 gallons of sap or so ...mad
e 1 quart and 1 pint from the bunch. guess I caught it just right.

[maplerookie]

As a Red Sox/Pats fan, can I just say there is something very wrong with reading "Boston, NY"?lol funny. when I lived in Alaska I had friends from Worchester. I got a couple of bo sox bumper stickers and planted one on a friends car ( a die hard Yankees fan) took about 3 weeks before I got the call laced with some very nice swear words. I still laugh about that today...that was back in the early 80's. go bo sox! I love it here...so much different than Boston Ma. both have their plusses and detractors though. good luck this season Eustis 22

[maplerookie]

When I boiled on steam pans, I sat the pans up and put sections of hollow rectangular steel between the pans so the flames wouldn't burn the foam line. In this photo, you can see the steel sections. I also poured sand around edges to keep the smoke from filling up the small plastic greenhouse I was working in.

8898

I also made some siphons out of copper pipe (not installed in this photo) after getting tired of ladling. You can read about how to make them somewhere in this forum - it's not obvious how to do it otherwise. I am working on doing just that during this lull --deep freeze. what is your boil rate. how far is your ramp from the bottom of the pans. I saw the thread on the siphons a while back. I will be doing that at some point. thanks for the good advice

[CampHamp]

I built a block wall just behind the firebox and dumped sand in front of it. It was 4" below the pans at the wall (the fire stays up high after the wall even through the void). Here's my design that shows the "wall":

8905

I got 8GPH.

[maplerookie]

I built a block wall just behind the firebox and dumped sand in front of it. It was 4" below the pans at the wall (the fire stays up high after the wall even through the void). Here's my design that shows the "wall":

8905

Here's a summary photo (https://scontent-a-iad.xx.fbcdn.net/hphotos-ash2/t31/457473_10150603224395885_326692659_o.jpg) of that first year of mine, declaring 8GPH boil rate and a picture of the siphons as well. I have my steel ordered for getting the pans up. your pictures did not come through. interesting that the fire stays up through the void so you had no ramp...just the void?. 8 gph is not to shabby at all.

[CampHamp]

I piled sand up in front of the wall for a steep ramp, but there was a void behind the wall before the smoke stack and the suction from the stack pulled the flame straight back, even when I would lift a back pan out! I tried to send a FaceBook photo link for the first time there, sorry - I'll edit it out if I still can. Here's an example (http://mapletrader.com/community/showthread.php?18050-Siphoning-between-pans&p=198282#post198282) of the siphons from this site.

[CampHamp]

Note that I didn't put the pans up on the steel because fire would shoot out the sides. I simply rested the pans on the block arch and put the steel rails between the pans also on the arch. If you want to slide the steel in between like I did, then the width of the steel must be wide enough to fill the gap. Another picture to help with what I'm trying to say. Let me know if you don't see the attachment.

8921

[maplerookie]

Note that I didn't put the pans up on the steel because fire would shoot out the sides. I simply rested the pans on the block arch and put the steel rails between the pans also on the arch. If you want to slide the steel in between like I did, then the width of the steel must be wide enough to fill the gap. Another picture to help with what I'm trying to say. Let me know if you don't see the attachment.

8921 Hey CampHamp..I think I get the general application of what you are putting across. none of the attachments came through. might be my computer though. the drawing is very clear though. I looked again at the siphon site last night. I have some copper laying around and will try it. just have to pick up a couple elbows and some larger caps.Thanks for the stuff you have sent. I like that most everyone on this site is willing to share their knowledge. Pray for a thaw if you are so inclined. !

[RileySugarbush]

If you don't like the little burn line, put your pans ups so only the bottom is exposed. But you will drastically reduce your evaporation rate. As I and others have mentioned before, the burn line will not be a problem in the resulting syrup. It will not taste burnt. Any black stuff filters out. You may have slightly darker syrup, but it will be delicious!

I boiled on a four pan drop in block arch like this for years and made great syrup. The last few years I had drop tubes in two of the pans and I made a lot of great syrup!

[maplerookie]

If you don't like the little burn line, put your pans ups so only the bottom is exposed. But you will drastically reduce your evaporation rate. As I and others have mentioned before, the burn line will not be a problem in the resulting syrup. It will not taste burnt. Any black stuff filters out. You may have slightly darker syrup, but it will be delicious!

I boiled on a four pan drop in block arch like this for years and made great syrup. The last few years I had drop tubes in two of the pans and I made a lot of great syrup!You are correct during the little thaw we had I made 3 pints it came out darker but it is a great tasting syrup..I am gonna see how much the boil rate goes down by lifting the pans up a bit .. I will surround them with bricks to keep the cold off of them. if it doesn't work to my satisfaction I will go back to the drop in full tilt. how did you make your tubes...copper or stainless?

[RileySugarbush]

You are correct during the little thaw we had I made 3 pints it came out darker but it is a great tasting syrup..I am gonna see how much the boil rate goes down by lifting the pans up a bit .. I will surround them with bricks to keep the cold off of them. if it doesn't work to my satisfaction I will go back to the drop in full tilt. how did you make your tubes...copper or stainless?

I made my first one with 1" copper tubes and caps. I made others with 1" water hammer arrestors which was easier.

[maplerookie]

I like the water hammer arrestor idea.. ready made tubes.. did you solder them to your pans? if you did you must have had some kind of fitting to rest on the bottom inside the pan. or not..

[CampHamp]

I've always heard that the boil-off rate is a measurement of "surface area". I wonder if "surface area" should be a calculation of metal touching fire or of metal touching sap. For example, campers may be familiar with a JetBoil which is a water boiler for hiking. If you look underneath (see here (http://assets.sectionhiker.com/wp-content/uploads/thumbskeep/5605007678_f672f773a4.jpg)) they have welded extra metal flanges to help with the heat exchange.

So, what if you added flanges of metal to the bottom of a flat pan like this? Would you get the same benefit as sap-filled pipes? I would imagine that pipes could burst steam and become dangerous, no?

[maplerookie]

I've always heard that the boil-off rate is a measurement of "surface area". I wonder if "surface area" should be a calculation of metal touching fire or of metal touching sap. For example, campers may be familiar with a JetBoil which is a water boiler for hiking. If you look underneath (see here (http://assets.sectionhiker.com/wp-content/uploads/thumbskeep/5605007678_f672f773a4.jpg)) they have welded extra metal flanges to help with the heat exchange.

So, what if you added flanges of metal to the bottom of a flat pan like this? Would you get the same benefit as sap-filled pipes? I would imagine that pipes could burst steam and become dangerous, no?I think once you get the pan hot the surface area of the liquid is what releases steam not the pan (metal surface area.)Although I know there is a lot of benefit in introducing more metal touching the liquid
adding some flanges may increase heat transfer in that camp stove but I think at the high temps we are firing at a couple of flanges wouldn't make a whole lot of difference. as for the pipes I don't think they are gonna burst.. they are open at one end and they are filled with liquid under negligible pressure at the depth of say 6 to 8 inches we are dealing with. burst pipes usually only result from being put under high pressure in a closed system. then freezing or high heat with no pressure relief apparatus will cause them to burst .So I think what a flue pan does is introduce more heat to the liquid causing more bubbles to rise to the surface and carry off more steam . Keep in mind I am not an engineer and I am just spouting off at the mouth. maybe one of the experts can chime in here!

[RileySugarbush]

I like the water hammer arrestor idea.. ready made tubes.. did you solder them to your pans? if you did you must have had some kind of fitting to rest on the bottom inside the pan. or not..

I punched holes in the pan, flared the copper 90 degrees, put bead of silver solder on each, then heated to fuse. Sounds simple, and it really is, but you have to be careful when soldering stainless. Use a liquid flux, clean the metal very well mechanically, and keep the flame very very low.

[Spolcik]

Ever consider finishing on propane fryer? If your batches are not very big it works good and easy to control the heat. I get it close and finish on my stove inside. Also works good but my batches usually not more than 3 to 4 gallons.

[lpakiz]

Any metal exposed to fire that is not liquid-cooled will not survive long at the 1500-2000 degree temps we get in the firebox. Water heaters are not running at these insane temperatures. I doubt those fins would survive a season.

[happy thoughts]

I've always heard that the boil-off rate is a measurement of "surface area". I wonder if "surface area" should be a calculation of metal touching fire or of metal touching sap.

It's neither. It's sap touching air. That's where evaporation takes place- at the surface of the sap.

[maplerookie]

It's neither. It's sap touching air. That's where evaporation takes place- at the surface of the sap. I'm with you on that one. I think that is what I basically said when I was spouting off at the mouth So if this is the case then the flues only act to get more heat to the sap so you get more of a fierce over all boil. so if on a flat pan you get a fierce boil going you should hve a pretty good if not comparable evap rate on the same size pan.. Correct?

[happy thoughts]

I'm with you on that one. I think that is what I basically said when I was spouting off at the mouth So if this is the case then the flues only act to get more heat to the sap so you get more of a fierce over all boil. so if on a flat pan you get a fierce boil going you should hve a pretty good if not comparable evap rate on the same size pan.. Correct?

That's what I'd think, too. Whether correct or not is a totally different ballpark :)

[CincySyrupPusher]

esleighton, That one sample on the left looks a lot darker than Grade B. At least based on the samples I have seen from the big boys.
I wander how thick it is... Seems it might have went a little past syrup in the finishing pan/pot or not filtered enough. IMO

My Dark Amber (First batch this year - about 60 gallons of sap)
900090029001

Just built a new 275 gallon evap (running 3 - 6" pans) w/ preheater.
9004
I can safely run them 3"-5" deep based on fire intensity to reduce boil-over. There is no concern for any burning on the sides, it happens. I heard mention of "stirring", not sure what needs stirred, but all I see it doing is knocking off the char/burned bits off into the increasing syrup. I don't touch it except to ladle (coffee mug) from back to middle and middle to front pan. One important thing to note, is to only go back to front to keep the gradient intact. I am still considering siphons to reduce my (human interference) and increase the reliability.

Adding drop tubes increases the surface area in contact with fire, makes it quicker to get to boil and faster to recover from additions (especially if not using a preheater - i.e. cold adds).

Hamp - The picture you shared is more or less what the BIG BOYs use (or those of us small timers that were brave enough to install drop tubes). It's basically a heat sink...
9005

[Big_Eddy]

It's neither. It's sap touching air. That's where evaporation takes place- at the surface of the sap.

Incorrect

When we boil sap - we transfer energy to the sap to overcome the latent heat of evaporation. The primary mechanism of transfer is conduction from the heated metal to the liquid sap. Simply - more heated metal to sap contact, more evaporation.

The rate of transfer to the sap is also a function of the flame temperature, the conduction rate from flame to metal, through metal, and metal to sap. Hotter flames - more transfer. Thinner metal / more conductive metal - more transfer. Insulating soot layer - less transfer.

Adding fins to either the outside or inside of the pan would increase the heat transfer rate on that side of the pan and therefore would assist. The downside would be longevity, cost, complexity and cleaning. The flue design is a good compromise. Significantly increased flame to metal and metal to sap surface area without complexity and without creating a cleaning nightmare.

Surface area of the liquid does not matter, although depth of the liquid does. Once the latent heat of evaporation is exceeded, the water turns to steam, the steam will rise and "escape" to the air unless it cools enough while rising through the pan to change back to liquid form.

Liquid surface area only affects evaporation rates when the primary mechanism is convection - e.g. water evaporating out of a pool.

[CampHamp]

Reading people's stories on this site led me to boil at about 1 1/2" deep of sap to improve the evaporation rate (I went from about 6 to 8 GPH on 4 pans). My ladle was 1" deep, so I could tell when I was running too low in a pan easily (even better when I got siphons - but still had to keep an eye out because they will fail over time).

Going from 4" deep to 1 1/2" caused more burning at the foam line when my pans hung in the firebox, So, I put my pans up to the ledge to keep the foam (and pans themselves) from burning. I didn't notice a drop in my boil rate by lifting them up, but you might if you're outside (especially in the wind). Outside boilers (who lift their pans up like this) have said to put bricks around the pan edges to keep them warm.

It was my first year boiling with the pans and I was finishing every batch to the end by dumping whole pans forward and back-filling with water (that's what people said to do). However, this was a pain and by the end of the season I was just leaving sap in the pans, finish much earlier and scoop syrup out from the front pan into a finishing pot as I boiled. I'd just wait for the next sap run to continue where I left off (honey bees found the syrup late in the season, so I needed to cover after the pans cooled).

My concern about adding pipes wasn't that the pipes would burst, but that when they boiled sap inside they would shoot sap upwards in bursts and wondered if you saw that and if it was dangerous at all? I have a wood-fired tub outside and sometimes I get that bursting effect of steam in the pipes.

Also, I was wondering instead of using pipes, if it would be as effective to add some thick metal flanges to bottom of the pans (running in the direction of the fire). But MapleRookie made a good point that most metals will warp in the firebox if not cooled by sap and so they may not last long. I'm not even sure if you could weld thick flanges to a pan anyway - it's not my strength. Anyway, I moved up to a "big boy" pan now and am tinkering with other things (like a cheap sap vacuum) but wanted to share what I learned so the next guy/gal might be more informed than I was...

[happy thoughts]

Thanks for clearing that up Eddy. I think I actually understood that:)

[CincySyrupPusher]

two drops of Extra Virgin Olive Oil in each pan (more as needed in the back "preheater" pan) and I didn't have a single bit of foam the entire time.

Can't taste a thing in the finished product.