Why 1.5 inches of sap?

[70 Buick]

I have often read that people run there pans with an inch & a half of sap while boiling
what is the reasoning behind this?
I have run mine at 3-4 inches & it boils great
does it evaporate faster at 1.5 inches?
Just looking for an explanation

[happy thoughts]

I only use small steam pans on a camp stove but I've also found that evaporation is faster when the pans aren't filled more than an inch or two. My pans are at most 3 inches deep.

The few reasons I could come up with for better evaporation at shallower depths is that shallower depths of sap come to boil faster so you're faster out of the gate. Also, when pans are more full, especially on a cold breezy day, the surface of the sap may cool enough to slow the evaporation rate. Shallower depths probably stay hotter when protected and warmed by the upper sides of the pan. And of course, toward the end syrup stage you want to leave plenty of room for that wild foamy boil that can just sneak up on you.

Anyway, someone else with a lot more experience than I do can probably tell you better but that's what I've convinced myself in the few short years I've been doing this in a very small way. I'll be interested in other responses because we're hoping to get a little bigger next year.

[Jeff E]

I would agree. Better, harder boils.
Also with divided pans, there is less mixing of the new sap and old. Keeps quality higher.

[70 Buick]

i don't have divided pans just 2, 6 inch deep restaurant steam pans

here is my setup 7 this is with 3-4 inches of sap in it
(I was fighting & losing the fight) she wanted to fill them LOL


I need proof as to why not , more than 1.5 inches

http://shootthebull.freeforums.org/download/file.php?id=210&mode=view

[PerryW]

two reasons:

1) When you run deep, the liquid is touching a larger area of is the sides of the pan, which results in more heat loss.

2) Running deeper means (on average), each sugar molecule is spending a longer time on the heat, resulting in a lower grade.

[ennismaple]

The explanation that Rejean L gave at our OMSPA meeting is when you add heat to the sap you cause liquid to turn into a gas bubble within the sap. It needs to burst at the surface to turn into steam and evaporate. If you run your pan too deep that gas bubble can be re-absorbed into the sap and you don't get any evaporation.

[Kev]

All I know is the lower I run the pan the more steam comes off. right there at the edge of Oh No :o it really rolls off and the fan sucking air through the hood can just barely keep up.and you can not see the other side of the pan but at 1.5 inches you can see the otherside of the shack between the pan and the hood. at 3 inches you could read a newspaper though the steam

[woodkutter]

If I run less than 2 inches at the float, it won't circulate very good at the syrup pan. It is over 80 feet from the float to the drawoff on our 5x16 and if we get too shallow at the syrup pan we can't get the level up fast enough. Once the temp goes past 219 circulation stops. Throw in some defoamer, shut off the underfire blower and open both doors will solve the problem. A partial bucket of sap can save the day too.

600 taps on gravity
3 buckets for the grandkids
600 gal. stainess zero tank for sap hauler
5x16 Vermont special
gas finisher
Grimm flat filter tank
Husky chain saw
monster maul with bent handle

[Brent]

All the above apply but let me see if I can summarize.
- over 1-1/2" the evaporation rate goes down

- over 1-1/2" and the turbulence tends to spoil the gradient from about 20% coming in to 66% at draw off.

- under 1-1/2" and it foams / bubbles so much that the flow slows and the gradient degrades ... you tend to get syrup in more than the last channel. You run the risk of scorching the pan in spots.

[TF Maple]

Seems to be more important on a divided pan. I just fill my tank and let it boil or steam as best I can get it. It still boils down no matter what level the sap is at.

[SeanD]

I had both problems this year. My first boil, I ran too low (about an inch) had so much steam I couldn't see the level getting even lower on one end of the channel. I fired it hard, it foamed, and I scorched the pan.

Since then I've been gun shy and brought it closer to 2 inches. I definitely breathe easier during the boils, but I've definitely delayed a few good draws. I'd get within a point of two then all of a sudden I'm 4 points away.

I'm feeling braver and more anxious to have better draws so on my next boil I want to work my way back down. What is it they say about moths and the flame?

Sean

[twofer]

This is my first season with a reverse flow pan but what I've found is that when I was running 2-2 1/2 inches in the pan I was getting more scale buildup on the bottom. When I run 1 1/2 inches there is hardly any build up and reversing the pans has been clearing out whatever buildup there was. My theory is that with a deeper level the draws were larger and more drawn out thus the sap sat in the pan longer and that gave the nitre more time to adhere to the bottom.

I won't run that deep again.

[Sugarmaker]

On our 3 x 10 King we try to boil about 1 inch to 1.5 deep. Seems to boil best at that level but as someone noted the bigger the rig the harder it is to keep the level during large draws of syrup.
We used the ah crap bucket a lot this year to make sure we did not ruin the front pan during big draws.
We did boil deep during some start ups due to flooding the pans the previous day.
Chris

[Haynes Forest Products]

I run about a 1/4" over the flues if it foams I settle it down with defoamer and let er rip.