Really, how often to add wood?

[stimyg]

I'm just getting started with my first real wood fired evaporator (smoky lake Dauntless). First test boil will be tomorrow.

I've read in many places that you want to cut your wood to wrist size - fine - and add the wood every 8 minutes or so - not so fine.

I don't need to be reaching maximum GPH boil at all times. My Dauntless is plenty big for the amount of sap I'll have, probably overkill. But I want the thing to boil and I want the sap to evaporate, and yet I'd love to be able to do the million other things I need to do on a given day without adding wood to the fire every 8 minutes.

So - obviously I'll be able to try this myself shortly. But, just so I can ballpark this, and get your opinions:

Every 8 minutes? Really?

(I have a mix of softwood and hardwood, mostly soft. Like 90% soft. I know that matters, and I know that there are a lot if variables, but big picture I just want to know if this 8 minutes thing is a perfect ideal that isn't strictly necessary, or if something like it is.)

[phil-t]

If you want syrup, you will need to tend your fire - 8 minutes, 10 minutes, 15 minutes, 20 minutes - you will take longer to get to syrup is all. Wood is not the only thing that needs constant attention in an evaporatopr. Still won't have time to tend other things. It's not a wood stove for heat, it's a "race car" and needs attention, a lot of it. Besides, once you start, you will want to get the highest evaporation rate you can, at least that's the way I am. Get your sap boiled and then go off and do your other things, You'll be more efficient, in the end.

[Russell Lampron]

The 8 minutes isn't cast in stone. When I'm burning mostly softwood I fire every 5 minutes and increase that time with hardwood. It all depends on when the stack temperature starts to drop. My arch is air tight and has air over and under the fire meaning that the wood disappears fast. If your not using a blower on yours your wood will last longer between fireings.

Like phil-t said an evaporator needs constant attention. The first time that you have a boil over or scorch your pan you'll know what we mean.

[ecolbeck]

I think it depends on what your goals are and what kind of pan you have. I know people who fill up the pan and throw wood in the arch once in a while when they get the chance. They make syrup slowly and in batches. They have open pans with no dividers.

If you have a divided pan, and you want to take advantage of it to make syrup continuously, then you need to fire very consistently to maintain a gradient.

[bigschuss]

If you're not in a big hurry to make syrup you can get away with throwing wood in your evaporator less frequently, but you will lose your boil, then you'll have to get it back again. If you have a pre-heater feeding your pan your depth in that pan will get all out of whack as you lose the boil but sap keeps on entering. As the others have said, it is much more efficient to do it, and do it right.

Every spring I save all of my yard chores for boiling time. I am lucky that my evaporator is about 30 yards from my home. I can easily keep my evaporator fed while I prune apple trees, tend a burn pile, do some small repairs to the house, work in the barn, etc. Yes, I have to stop and walk back to the sugar house every 10 minutes or so. But I get a ton of work done. I also log probably 3 or 4 miles of walking during the course of the day.

[buckeye gold]

I agree with Phil-t, run the evaporator at peak efficiency and then go work. You can easily turn a 4 hour boil into 6-8 hrs if you don't tend your fire and you'll have a whole pan batch boil. I have a moto I learned after a couple scorched pans......BAD THINGS HAPPEN WHEN YOU WALK AWAY FROM AN EVAPORATOR

At least set your float to run at 21/2 -3 inches in your pan and give yourself some margin, if your walking away. Maybe yoda's advice is good for sugaring to when he said, "Do. Or do not. There is no try- "That is why you fail.”

[Sugarmaker]

Stay there fire every 8 minutes and make the syrup. Its not the time to be off doing other things, unless the pans are full and you just have some kindling in there to keep it warm. After that it really is about your comfort zone of the time you have to make the sap you have into the syrup you want. Dont want much much syrup dont boil much sap very long. Most of us want to get the syrup made rather quickly to maintain the class of syrup. But some dont and added boiling time can give you darker syrup color, which could be desired.
I am not sure how big your evaporator is? They boil at different rates. From gallons per hour to gallons per minute. You'll get the hang of it. Just try not to burn the pans right away. No fun there.
As my friend Jim has noted many times, "Your only 10 seconds away from disaster at any time, when running one of these!"
Keep boiling.
Regards,
Chris

[Dave Puhl]

With my 2x6 I use a timer 7-8 minutes. I run an inch or so deep in the sugar pan and like was said don't walk away when you are boiling

[wnybassman]

I fire every 5 to 8 minutes depending on wood. If I went 15 minutes I wouldn't even have a hot coal left in the firebox.

Not sure I have ever heard of anybody wanting to slow down the process. lol

[GramaCindy]

I wish there was a LIKE button for this Phil-t

[maple flats]

Before I had air over fire (AOF) I added wood by a timer every 7 minutes, with AOF I add every 9 minutes, except if I'm having an open house, then I slow it to 12 minutes.
The main thing is that you want to pay attention to the evaporator when you are boiling. Don't think the boiling can be done as a "when you get a chance" firing schedule.
If you are boiling alone as many of us do, set up a routine. While I'm running the evaporator when my loud timer rings, I reset it, Set the wood close to the fire door, open the door, then add wood and close the door. Then I check the auto draw (or the temperature if no auto draw), I look in the syrup pan to check depth and if I'm getting indications of niter build up, then I walk around the evaporator, checking all 3 float boxes (I have a raised flue , 2 are float boxes, one is the draw off) I check the RO pressure, I check the site gauge on both the rear pan and the head tank and as I walk arond every few times I wipe the outside of the pans and hood with a wet paper towel. By then it will be almost time to add wood again. By the way, my defoamer is automatic, I used to add drops every fueling, not I just check the level of the defoamer in the dispenser maybe every 4 hrs but I verify thru a site glass that it is slowly putting a drip in. That I set to drip every 60-75 seconds, I boil concentrate, if I get any foaming in the syrup pan, I adjust the defoamer to slightly faster, it dispenses into the flue pan right where the in-coming concentrate enters the flue pan. Along with all of that, if my wood reserve in my wood rack is getting low, I open the doors to my wood storage and add 2-3 arm loads. That all takes 8-9 minutes if done properly. When you are boiling, that needs to be your focus.

[johnallin]

I'm just getting started with my first real wood fired evaporator (smoky lake Dauntless). First test boil will be tomorrow. I've read in many places that you want to cut your wood to wrist size - fine - and add the wood every 8 minutes or so - not so fine.

I don't need to be reaching maximum GPH boil at all times. My Dauntless is plenty big for the amount of sap I'll have, probably overkill. But I want the thing to boil and I want the sap to evaporate, and yet I'd love to be able to do the million other things I need to do on a given day without adding wood to the fire every 8 minutes... but big picture I just want to know if this 8 minutes thing is a perfect ideal that isn't strictly necessary, or if something like it is.)

No it really isn't. It sounds like you're trying to make syrup without going full metal jacket and yes you can, it will just take longer. You can "multi task" as long as you keep a fire going and sap in the pan.

At a depth of 2" that rig holds about 8 gallons of sap and evaporates about the same per hour. Fill it up to 4" and you should be good for an hour- or two - without worry of burning your pan. Throw some wood at it every 15-30 min - just enough to evaporate water - and eventually you'll have syrup. It will be dark, it may be smokey tasting and it will drfinately take a Long Time, but you will have syrup non-the-less and will taste great.

Sounds like you've got a nice setup that you can keep going in the background, and do something other than standing around watching water boil. Also sounds like the first time you taste that syrup, you're gonna be hooked. So be prepared to drop everything when the sap is running and for a 4-6 week period each spring be consumed with learning the art of making maple. First and most important is have fun, everything else will fall into place.

[Big_Eddy]

You can run shallow and fast burning rocket fuel every 5 mins, or deep and slow burning cordwood every 30 mins. It all makes syrup.

Wont take you long to get a feel for your evaporator. Big wood burns slower and lasts longer. Get a sense for how long your wood lasts. You want to refuel before it is gone.

Nothing to worry about while you are still sweetening your pans but once the gradient is in place, walking away is not recommended. The problem with the stoke and return approach is there is a short time window between almost syrup and way past syrup and if you are not there during that 3 to 5 min window bad things happen.



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[woodguyrob]

I have 4 boils under my belt this season so far with my Dauntless using a flat pan. If you use all / mostly hardwood expect to end up low and a little low slow on the boil as you'll likely find coals building up blocking some of the air flow. That may fit your needs.

If you're going to push it, a good mix of hard and soft works really well. We load every 4 minutes using a mix of dry fist size and under wood for a hard boil. at 1.5 inches in depth. We use a 5 gallon feeder bucket and sight glass.

I'd be leery of walking away too much from the boil until you get the feel for it.

[pyro]

Yea, I hear everyone say they load every 8 min. I just can't imagine this - sitting around for 8 hours loading that often. To much like work and not enough like a hobby.

I batch boil in a flat pan, and load anywhere from 15 - 30 minutes depending on what I'm doing. I would say I can't go longer than 30 min as boiling stops. It really depends on the size of the wood you put in. It will become very obvious that small pieces creates very hot fires, gets aggressive boiling and don't last long. Large pieces last long, but don't get that extremely hot fire.

Get a flu pipe thermometer. Watching the flu temp is much quickeir than watching the boiling in the pan. This is often delayed given the volume.

[stimyg]

Ok thanks, this has all been very helpful. And yes, good point about not leaving once the divided pan starts producing actual syrup. I’m sure I’ll be watching it like a hawk by then...

[DrTimPerkins]

Batch systems are more conductive to filling up, firing hard, and leaving it to run for a while unattended (after one gets comfortable with how long you have to boil off a certain amount of liquid).

Continuous flow systems are FAR less amenable to that style of operation. Float malfunctioning, foaming, sap supply issues, niter clogging pipes, ect. can all conspire to result in burned pans very quickly if unattended. The race car analogy is a good one. Your best bet is to not take your eyes off it. You don't have to search very long in this forum to find threads of burnt up pans with the phrase, "I only stepped away for a minute" to understand that evaporators are not meant to be unattended. We never walk away from a running evaporator without announcing to others in the sugarhouse to keep an eye on it. At best a burned evaporator will ruin a batch of syrup. Even worse it can result in a lot of wasted time cleaning the pans (a rather difficult chore). In the worst case...buy a new pan.

[fisheatingbagel]

There are a few variables to consider. In a continuous flow setup, you want the fire to be as consistent as possible. If your fire burns hot for a bit, then falls off, the syrup will mix together in the pan, making it harder to get a gradient going, and getting enough syrup in the final section to draw.

Depending on the type, size and dryness of your wood, you can extend the time between firings and still maintain a consistent fire by burning larger pieces of hardwood - the larger the pieces the longer they burn. You could probably extend your interval up to 15 minutes or so by burning bigger or unsplit rounds.

On the contrary, if you want to maximize your output, burn small dry pieces of softwood. I've been burning some 2x scrap I got from an axe throwing place, and I need to fire every 5 minutes to keep the fire consistent. It really boils though with the softwood....

[donka]

What are you using for a pan?
At home I have a a 1/2 pint that I batch boil. When I want maximum production I run the levels low and don't leave the evaporator unattended even for a minute. I maybe get around 7gph doing this. Whenever I have stuff I want to do in garage, yard or need to collect sap I run the pan at 3+ inches with a steady flow of sap coming into pan from a preheater. I load the Firebox with hardwood and do what I need. Every two hours I come back to shack and manually add sap with a saucepan throughout pan slowly so you don't warp pan. I bring levels which have reduced by half back up to 3+, fill preheater, load wood and repeat. I have been doing this for 10 years with great success. You will only get a 3-4 gph average but it's a relaxed affair. I only put a maximum of 120 gallons of sap through before I pull the batch.
If you have a flued pan I wouldn't try this. You'll have to stay within eyesite and monitor continuously.

[stimyg]

I have a Smokylake Dauntless 2x4 divided pan. I ran it for the first time today. I get it. It goes through a lot of wood fast. And to get the best boil you do want to run those smaller logs and those do burn up quick. And you do really get addicted to keeping up a monster boil going. If anything I wish I could feed it more often.

Also, since I was just getting started and not close to drawing off, I was able to step away if I needed to. Although perhaps I messed with my gradient.

But, yes, I get it now. I've got a related question but I'm going to post it fresh in another thread. Thanks for your help!