To foam or not to foam?

[Lyle]

This may be a dumb question but here goes: Will my rate of evaporation increase or decrease if I let the flue pan foam,. The boil looks more vigorous when it's foamy but it seems to evaporate more quickly without.

[treehugger]

Evaporates quicker without foam. Otherwise the nice people at atmos (defoaming stuff) would be on unemployment.

[maple flats]

That's right, the foam restricts the steam escape, no foam is much faster boil. However, do not over do it. Generally 1 drop at each fueling into the flue pan at the longest path to the syrup pan is good. Occasionally I even only need 1 drop every other fueling, but those times are rare.
Dave

[PerryW]

I let my back pan foam more than a lot of people and use the defoamer mainly to prevent boil-over. Seems like when I defoam the back pan, the sap sometimes spits out of the pan and I feel like I'm losing sugar.

[red maples]

That's right, the foam restricts the steam escape, no foam is much faster boil. However, do not over do it. Generally 1 drop at each fueling into the flue pan at the longest path to the syrup pan is good. Occasionally I even only need 1 drop every other fueling, but those times are rare.
Dave a drop every firing wow. I only add it when I see foam. never checking it upon firings though. I just use organic cooking oil. I put it in one of those pump and spray bottles works really good because it sprays so the foam drops quicker. I also use splash guards so I don't loose too much sugar. it will boil so hard it spits out of the pans!!!

[sugaringman85]

i went to a seminar where glenn goodrich had a talk about boiling and he said the more consistent you can be with your evaporator the more consistent you will make syrup. one of the points he made is that if you add a couple of drops every time you fire, which should be every 10 min or 6 min depending on how your system fires. he said that if your consistent with your defoamer it will reduce the amount of foam throughout the evaporator. I've even seen automatic drippers in the float boxes on some of the bigger rigs.

[sugaringman85]

foam can also consume the pan and potentially scorch the pans because there is not enough liquid touching the pan

[Lyle]

Thanks everyone! It's a great help to be able to ask the Pro's! I'm trying to get all I can out of my 2x6. I'm having difficulty getting much over 30gph. With my sugar content struggling to reach 1.5% I need all the evaporation I can get!

[danno]

Don't know how you guys get along without so little defoamer. I used to use it very sparingly, a drop or 2 at each firing, but have recently started using more. I'm boiling 8% sap in a 3x10. I've been checking the syrup carefully to make sure taste or defoamer slick is not showing up in my syrup.

At 1 to 2 drops a firing, I was still boiling out of the flue pan 2 or 3 times a night and was having to add an additional drop or two in my syrup pan, sometimes as often as every 3 minutes to keep the foam from going over my center dividers (12" high dividers).

Increasing my defoamer has made the boil/draw soooo much smoother - no boil overs in the flue pan and much more controlled foaming in the syrup pan and have not had to add defoamer to my syrup pan - which is a very good thing in my mind.

[ennismaple]

Bruce Gillilan from Leader did a Boiling 101 talk at our local OMSPA meeting and in his opinion most people don't use nearly enough defoamer. He recommended 6-8 drops every 5-8 minutes for an evaporator like our 3.5'x14' Force 5. bruce said that there is no foam in his flue pan when he boils. The theory is that the foam makes some of the steam that has been evaporated out of the sap to condense again and drop back down into the pan. Without foam the steam is free to go straight up the stack

I'm not sure if we'll use that much defaoamer but we'll certainly use it more regularly. Previously, we were only filling the defoamer cups (using Kasher powder defoamer) every 2-3 hours and sometimes it would foam up into the drip rails on the steam hood.

[Gravitytom]

ennismaple would you have a picture of how your arc is bricked behind the wall that is shown in your photos. I have a new arc from Patrich (3x12) which is a very close copy of a force 5, and I have not been able to do much better than 90 Gal an hour with a preheater. He has my wall going stright across and I see yours is in a vee shape and on mine, behind the wall it goes stright down about 10 inches. When I am boiling I don't get much boil in the back of my sap pan.Thank you

[ennismaple]

Sorry - what you see is all I have for pictures. The arch comes pre-bricked so I didn't take many pictures of it.

[Vermont Creation Hardwood]

On the question of to foam or not, I don't foam. Nor do I use defoamer. The advantage of being a small producer with a flat pan is that sap in my pans never foams and so I don't need defoamer. I finish off inside on the stove and mechanically defoam there.

I don't want any additive in my syrup. Perhaps most of the defoamer evaporates, but it is still an additive and some will remain.

[ennismaple]

When the fire beneath the flue pan is 2100 F the only way to keep the foam below the hood is to use defoamer. We use it sparingly and it does evaporate by the time it reaches the syrup pan. We made almost 200 gallons of syrup and used a toal of about 30mL of defoamer over 3 days.

[PerryW]

yep, I dare say 99% of all maple syrup produced in the world has seem defoamer. 3 or 4 drops of corn oil for me every ten minutes or it's a melt-down Scotty!

[Vermonner]

I'm on a 17K tap operation this year running a 6x16 Leader oil fired rig and we defoam at regular intervals. Every 5 or so minutes in the flue pan and on occasion (1/2 as often, at most) in the front pan near the draw off.

[adk1]

MY routine is to add a drop of defoamer after firing each time. so that is basically every 7 minutes