is preheater really worth it?

[Benewing]

Hello All,

I am running a very DIY setup compared to everyone else's but I have a question about preheaters. Right now, I am running a setup with two hotel pans, end to end, and batch boiling everything. Usually I just add cold sap to both and let it boil down a while, and add more. This boil I'm going to use one as the preheater and use a ladle every so often to let the other one keep a roiling boil. Do you think keeping a rolling boil will actually helps with boil times? Or is it just about pumping BTUs into the sap?
21124

[TheNamelessPoet]

I am interested as well. I have a pan like yours, and a regular pan that I ladeled from one into the larger one my last boil.

(hot trying to hijack OP, just looking for the same answer :-) https://uploads.tapatalk-cdn.com/20200305/44e798e9b9694e1d5db8b6dbeeace5d8.jpg

[Sugarmaker]

The answer is of course yes. But what is your goal? More sap? More syrup? both = More boiling. Do you want to reduce boiling time? Then bigger or more efficient system is always better. A properly designed preheater on a std evaporator can be expected to improve your evaporation rate by maybe 10%. Get a bucket R.O. Yo will be happy. I dont have one and am not endorsing them but folks that I have heard that have them at your level are generally happy.
Keep boiling!

Regards,
Chris

[Benewing]

I have a small RO system that works pretty well, but my main question is, without adding anything (like a stack preheater) does it cut boiling time to have one pan at a constant rolling boil while I add cold sap to the other? Or is it just about pumping BTUs into the sap whether it's at a rolling boil or not?

[In da bush]

I’ve been on both sides of pre-heating and I will say hands down that preheating is the only way imho. If you can fashion a hood to capture the heat of your steam and put a pre-heater inside the hood, you’re gonna bump evap rate up. Teach yourself how to solder and build a preheater. I built a preheater similar to the one that smoky lake maple sells for around 1k,cold sap going in and 170-180 after it’s gone through the preheater. I cobbled a hood out of a stainless drum from a clothes dryer that I cut in half,cost me $0.00.
Good luck and good sugaring!!

http://mapletrader.com/community/attachment.php?attachmentid=19500&d=1550849505

[Sugarmaker]

Well We boiled with cold sap going in for a long time. I would think its going to shorten your normal 4 hour boil by 15 minutes. Is that enough? Just a guess. Having hot sap entering the boiling syrup will sure help. So what is your R.O. sap going in at? You can recirculate it to get higher sugar therefore reducing boiling time too.
Keep boiling!
Regards,
Chris

[TheNamelessPoet]

I have a small RO system that works pretty well, but my main question is, without adding anything (like a stack preheater) does it cut boiling time to have one pan at a constant rolling boil while I add cold sap to the other? Or is it just about pumping BTUs into the sap whether it's at a rolling boil or not?if he is asking the question I think he is asking, no one has answered it.

Benewing, your setup right now (based on picture) has 2 6" deep pans about 22×12 ish. are you asking if you should ladle from pan 1 into pan 2, while constantly adding new sap to pan 1 that is not preheated?

[Benewing]

Yes! That's exactly what I'm asking. Thank you for putting it better than I could! I'm sure a preheater setup would help a lot, but I'm just wondering if, with the setup I have now, it is better to ladle between the two so I can keep a rolling boil in one and add cold sap to the other.

[berkshires]

This boil I'm going to use one as the preheater and use a ladle every so often to let the other one keep a roiling boil. Do you think keeping a rolling boil will actually helps with boil times? Or is it just about pumping BTUs into the sap?
21124

I have a similar setup to yours. Don't think of one pan as a preheater. You want both pans to keep a boil going as much as possible. Figure out which pan runs hotter, and slowly add small amounts of sap to that one. Try to keep it at a boil as much as possible. As you go along, ladle boiling sap from that pan to the other pan. This is the way to keep a boil going on both pans as much as possible. When a pan drops below boiling, you basically kill your evaporation rate in that pan.

This will also result in you having a sap pan and a syrup pan. At some point you may be able to start ladling near-syrup (nearup) out of the syrup pan.

Good luck!

Gabe

[berkshires]

Here's a link to the thread where I discussed this. http://mapletrader.com/community/showthread.php?28173-Question-sap-movement-using-two-steam-tray-pans As I mention in that thread, once I started it doing it right, my boil rate increased by a third. Definitely worth doing right!

GO

[For_the_kids]

up until this year I used 4 steam table pans set down inside the fire to act as drop flue pans. I had a small pump system that would trickle feed cold sap into each pan seperatly. This was all on a concrete block arch made from the big roadside concrete blocks. I never lost a rolling boil doing it this way and I was able to hit 12 GPH several times throughout the season but 10 GPH was very normal. I never ladeled any sap until the end when I would move the sap forward to finish up, once a pan was empty I would fill it with water. I added a picture of what my setup was. when I acheived 12 GPH I would block the top 2/3 of the door opening with a big green log up on a couple bricks so that air was drawn from under the fire grate. once my door was burned up too much I would make a new one. :)

[tommymc]

Hello All,

I am running a very DIY setup compared to everyone else's but I have a question about preheaters. Right now, I am running a setup with two hotel pans, end to end, and batch boiling everything. Usually I just add cold sap to both and let it boil down a while, and add more. This boil I'm going to use one as the preheater and use a ladle every so often to let the other one keep a roiling boil. Do you think keeping a rolling boil will actually helps with boil times? Or is it just about pumping BTUs into the sap?
21124
I think you would benefit from a pre-heater. In my opinion, it's all about maintaining the boil, and you're losing the boil every time you add cold sap. You might consider a DIY gravity fed preheater like I use. It consists of a tub (which I lay a filter cloth over) with a short pipe and valve draining out the bottom. This is attached to copper tubing coiled around the stove pipe and draining into a corner of the pan. I have the coil wrapped with aluminum foil to hold the heat. The idea is to create a trickle of warm sap that (ideally) matches evaporation. It can be a balancing act getting the trickle just right, but it generally works well. You have to be careful to keep a steady flow, otherwise the sap will boil in the tubing and plug it up. When all the sap is gone, I redirect the end of the tubing off to the side and just run water through the tubing until I finish the boil.

21217 21218 21219

[maple flats]

I’ve been on both sides of pre-heating and I will say hands down that preheating is the only way imho. If you can fashion a hood to capture the heat of your steam and put a pre-heater inside the hood, you’re gonna bump evap rate up. Teach yourself how to solder and build a preheater. I built a preheater similar to the one that smoky lake maple sells for around 1k,cold sap going in and 170-180 after it’s gone through the preheater. I cobbled a hood out of a stainless drum from a clothes dryer that I cut in half,cost me $0.00.
Good luck and good sugaring!!

http://mapletrader.com/community/attachment.php?attachmentid=19500&d=1550849505
I'll bet your wife got upset when she went to dry the cloths!

[In da bush]

I'll bet your wife got upset when she went to dry the cloths!
There’s a reason I’m not married😜🤣
It was from the "pile of treasures",no working clothes dryers were harmed in the construction of the hood

[Trapper2]

21287
I constantly trickle 40 degree sap into my top pan to preheat and then it exits that slowly at 80-100 degrees. Darn sidways picture.

[woodguyrob]

I think a pre heater makes a huge difference. A coil preheater is easy to make and has a short learning curve. When I originally started using mine I did what what tommymc did., run water through it when there was no more sap. I stopped doing that and found no issues with burnt sap in the tube. When I start a new boil I just catch the first pint or two in a coffee can in case there's anything burnt in the tube. I us 3/8" copper. It also comes in handy to make hot water at clean up.

[Michael Greer]

It's all about BTUs. You get them from your fuel, and add them to your liquid. A preheater should capture wasted or lost BTUs from steam of flue heat. Steam is a better heat-transfer medium. Simply adding more fuel isn't really a preheater, jut a bigger evaporator.

[Muddy Bottoms]

A preheated pan can be made very simply.

Another restaurant tray, a step drill, and a cheap brass ball valve with a threaded nipple on one end. The steam trays are typically 24 gauge stainless. Very thin. Once the right diameter hole is drilled, the threaded nipple will screw right into the tray with nothing else on the backside.

I like to set mine on trickle so I get a few minutes to do other stuff. If you set that trickle tray on top, you would only need to ladle from the one pan to the finish pan without losing to much boil. HTH.

[Gremlin]

There’s a reason I’m not married😜🤣
It was from the "pile of treasures",no working clothes dryers were harmed in the construction of the hood

I knew there was a reason I am keeping that old dryer stored in the shed. Have to take a closer look at that.

(In da bush - Mid Coast Maine - Back in the day I spent several years in Rockland and some time up in Gods Country - Lubec. Beautiful country)

[In da bush]

It is indeed beautiful out here,I grew up in the Midwest and did some time in the NE wisco area. I’m a big fan of western and northern wisco these days. Happy boiling!!!

[Gremlin]

Preheat by all means. The other day I did 11 gph in my first hour with a 2x3 pan.

But the pan had some help. I had 4 buffet pans on turkey fryers going at the same time.
I only had 20 gal of sap to work with so I emptied those buffet pans pretty quick so didn't use much propane at all and never lost the boil.

[therealtreehugger]

Trapper 2 -
With your preheater pan on top of your main pan, do you get condensation dripping back into the main pan?

[jrgagne99]

From an engineering and physics perspective, you're not gaining anything unless you catch the condensate before it drips back into the pan. That was my experience back in the day too. I saw a noticeable difference when I jacked up the preheater pan and started channeling the condensate off into a bucket on the side.