freezing sap

[harrison6jd]

i have read in several places that when the sap in the buckets freezes, the frozen part is all water and no sugar. if this is correct, has anybody experimented with freezing the sap and removing the ice to have a higher sugar content? beneficial financially? cut down on boiling time? how would this process compare to RO? just thinking out loud. thanks

[Bucket Head]

Ice in the sap is often called "Mother Natures RO". It does'nt compare to actual RO processed sap, but discarding the ice will cut down on boiling time a little bit. There is some sugar in the ice, but 99% percent of us chuck the ice when we find it in the buckets. Years ago before we had tanks we held our sap in plastic barrels. When we had a deep freeze the barrel itself would have a couple inches of ice stuck to the inside and the surface of the sap would freeze also. I would hatchet a hole in the ice and pump the "concentrated" sap out. It was'nt fun getting the ice out but it made for shorter boils, which was great!

Steve

[Jmsmithy]

What if entire bucket where to freeze? Is sap ok to defrost and boil?

[happy thoughts]

What if entire bucket where to freeze? Is sap ok to defrost and boil?

Yes. Freezing helps preserve it. You can even freeze finished syrup

[StayinLowTech]

This week the same question bugged me, so I took some ice and sap from the same tank and put on the refractometer. The ice when melted was 0.6 and the sap was 2.3. So figure for yourself whether it is worth it to boil it.

[Maplebrook]

I have finally convinced one of my kids to do a science fair project on this...stay tuned!

[Rinkus]

Today when I went to collect sap most of my buckets were frozen solid. Two of them that were attached to the largest trees were full but about two thirds frozen. I carefully pulled out the frozen chunk, giving plenty of time for any liquids to drip free before discarding the ice. I placed a drop of today’s sap on a refractometer and had a reading of 5.5 brix. I will be straining all for the ice out of my sap after today.

[Run Forest Run!]

I tested the sap under the ice in one of my buckets and it read 6%. There was a happy dance right on the spot.

[harrison6jd]

all good responses which is what i expected from this site. quality info with no bashing. that being said, does anyone feel it is worthwhile to artificially freeze the sap as opposed to a RO setup. i guess im looking for ways to boil less and get more. best of both worlds you know. debating on a better cooker. right now im on a 30x48 flat pan with forced draft.

[Big_Eddy]

Ice will freeze "sugar-free" as long as the temperature stays above -9 degrees C, effectively concentrating the sugar in the solution and removing the water. Below -9 degrees C, the sugar solution will also freeze.

A typical chest freezer is set at -18C.

So - if you got an old chest freezer and adjusted the thermostat to ~-7-8 C, you'd be able to freeze the water out of the sap leaving the concentrated solution behind. If you just toss your pails of sap into your home freezer, you'll end up freezing your pails solid - sugar and all.

[GV2]

Having lived in Missouri for a few years I needed a “show me” on this subject. I am running 35 buckets this year in Western MA. I collected 25 gallons in the beginning of last week and then everything froze up. I had my 2% sap in one container and my 1% in another. After I separated and melted the ice from both containers I ended up with 7 gallons of melted ice total (out of 25!). I checked the sugar contents of both ice melts and they both registered around zero sugar contents. I had similar results last week.
So now I am a true believer that this is a bit of natural RO. I am surprised someone has not invented and marketed a pass-through sap freezing device to help the sugar industry.

[moscowmule]

Ice will freeze "sugar-free" as long as the temperature stays above -9 degrees C, effectively concentrating the sugar in the solution and removing the water. Below -9 degrees C, the sugar solution will also freeze.
.

just to clarify for us southerners, -9 C is 15.8 degrees F

[jrgagne99]

I am surprised someone has not invented and marketed a pass-through sap freezing device to help the sugar industry.

Especially since the heat of fusion for water is only 334 kJ/kg, compared to the heat of vaporization of 2260 kJ/kg. This means that it takes a lot less energy to freeze water than it does to boil it. Of course, RO blows both of these methods "out of the water" (pun intended). I don't have specific energy costs at my fingertips, but I expect it would be in the tens of kJ/kg, maybe less.

In any case, it takes heat to initiate the Maillard reactions for color and to give it that "maple" flavor, so you'll need to boil it at some point regardless. Otherwise, you just have flavorless sugar syrup.