Sweeten the Pan

[TwinBay]

I have a 2x4 pan.
If I get 30-35 gallons of sap.
How long would I have to boil this, to sweeten the pan, so the sucker wont freeze?
We can only get up to boil and finish batches on the weekend.
Appreciate the advice.

[Big_Eddy]

30-35 gallons is not enough to finish in a 2x4 flat pan. You need ~80 gallons before you'll be able to finish a batch off in your pan. But it really doesn't matter if a flat pan freezes. Won't hurt anything. A lot better than having sap sit warm for the week.

35 gallons will take 4-6 hours to boil off allowing some time for start up and shut down and depending on firing and wood.

2 options - Boil down as low as you are willing to take it, them pour it off into a stainless container and place it in the freezer until next weekend. A wheelbarrow full of snow in the shade works as well. If the weather will be cold all week, leave it right in the pan.

Or
Boil down as far as you dare in the pan, pour into a stainless container and boil off on propane until you're down to ~half again then test your density and enjoy

[TwinBay]

Thanks Eddy;
My real question I guess was answered by your first point.
I will have no shortage of sap, but wont have enough time to boil and finish this weekend.
I really just want to know how long to boil, so its still safe to leave for a few days.
Should have 90 gallons in total. if I get it reduced down to 30 gallons- can I leave it in my 2x4 pan without fear of freezing or spoiling for 3 days or so?

[Big_Eddy]

If your concern is freezing, just boil what you can leaving your flat pan with less than an inch in it. Will not be an issue even if it freezes solid. (Flue pans can be a concern)

If your concern is spoiling - then make sure whatever you do boil is taken as close to syrup as you can, and whatever is not boiled is kept cold. Don't dump a lot of sap in and boil it down a little, instead boil a smaller amount down as close to syrup as you can. 12% concentrate spoils faster than either sap or syrup.

[PerryW]

for the record, I have let my flue pan freeze solid many times over the past 24 years. I just boil it down to 1/2" or less above the flues The 7" deep flues seem to have plenty of flex to allow the ice to expand, and I have never had a problem.

[wnybassman]

12% concentrate spoils faster than either sap or syrup.

Just curious, what's the science behind that?

[TwinBay]

Very interested to learn that boiled, concentrated sap spoils faster.
Do you know why that is ??
I will research more myself and post back here.
Looking forward to learning more answers...

[Mikeh]

I was at the winter conference at Anderson's and a rep was talking about RO's. He said that after concentrating in a RO there is more sugar around for the bacteria to feast on. He said that if you store raw sap for 3 days you lose some of your sugar % beause the bacteria eat it. If you store concentrated sap for a much, much shorter period of time you lose the same amount. I think in 3-4 hours the concentrate degrades as much as the raw does in 3 days but I can't remember exactly. So based on that I'd think it applies to spoilage as well. Of couse, since I didn't have a RO, I wasn't paying enough attention so hopefully someone else can corroborate my poor memory :)

[wnybassman]

I was at the winter conference at Anderson's and a rep was talking about RO's. He said that after concentrating in a RO there is more sugar around for the bacteria to feast on. He said that if you store raw sap for 3 days you lose some of your sugar % beause the bacteria eat it. If you store concentrated sap for a much, much shorter period of time you lose the same amount. I think in 3-4 hours the concentrate degrades as much as the raw does in 3 days but I can't remember exactly. So based on that I'd think it applies to spoilage as well. Of couse, since I didn't have a RO, I wasn't paying enough attention so hopefully someone else can corroborate my poor memory :)

I can see that after running through a RO without boiling. But if it has been boiled and got to that same percentage, I would think it would keep longer because it has been sterilized.

[wnybassman]

I was at the winter conference at Anderson's and a rep was talking about RO's. He said that after concentrating in a RO there is more sugar around for the bacteria to feast on. He said that if you store raw sap for 3 days you lose some of your sugar % beause the bacteria eat it. If you store concentrated sap for a much, much shorter period of time you lose the same amount. I think in 3-4 hours the concentrate degrades as much as the raw does in 3 days but I can't remember exactly. So based on that I'd think it applies to spoilage as well. Of couse, since I didn't have a RO, I wasn't paying enough attention so hopefully someone else can corroborate my poor memory :)

I can see that after running through a RO without boiling. But if it has been boiled and got to that same percentage, I would think it would keep longer because it has been sterilized.

[TwinBay]

I agree.
Coincidentially ever notice how long the hummingbird feeder stays clear.
Its sweet water ???

[Big_Eddy]

Just curious, what's the science behind that?

I'm not a scientific expert, but it was explained to me like this.

Syrup has a high enough sugar concentration that only a very few types of bacteria can survive in it, and therefore it doesn't spoil fast even when stored in warm conditions exposed to air. (Like sweet left in your evaporator between boils)

Sap has a low concentration of sugars, and while the bacteria can live in it fine, they do not multiply very fast as there is not that much food around. Decrease the temperature and you decrease the multiplication rate almost to nothing - that's why we can store raw sap for a long time on ice. Increase the temperature and the multiplication rate increases.

Concentrated sap has an ample supply of sugar to feed the bacteria, so even at the same temperature the overall rate they multiply at is increased.

Boiling the sap does kill off all the existing bacteria in the pan, but there are more around and they will start to multiply again. While it was not part of the information that was shared with me, I expect that concentrate from an RO would spoil faster than concentrate created by boiling.

My point to the original poster was to either keep his sap on ice or boil it off, but not to pour it all in the pan, warm it up and partially concentrate it, then leave it for a week to spoil.

[eustis22]

I have a 2X3 divided pan. By the calculators floating (npi) around here it should take 120-160 gallons to sweeten this pan. Does it have to be a continuous boil of the amount to sweeten or can I boil 80, collect another 80 and boil that (within 3 days, give or take, assuming cold weather)?