freezing sap

[40to1]

When the recent cold snap descended upon Massachusetts, I had about 65 gallons of sap in storage. It was about 2-2.5%
For ease of freezing I poured much of it off into food-grade buckets. Over the next several days I decanted the freezing sap and tossed the ice.

By the end of the week the sap was just about at 10%.

While it stinks not to have had sap flow this week, it is mitigated when I think about how much firewood I saved!
Boiling 10% sap is great! I want an RO!

8986

[PerryW]

freezing is the poor man's RO.

[SeanD]

Awesome! I started doing that with what I had in my barrels and the sweet I pulled off of the pans, but by the second morning, I couldn't break through the layer of ice. It was COLD. I was afraid to use a tool or put too much into it because with my luck I'd punch a hole right through the barrel.

Hey, what happened to that storm trooper you had working for you? I was digging that.

Sean

[SmellsLikeSyrupNH]

Walked in my woods yesterday and empties the buckets I had from last weekend...big chunks of ice in them all, but holy crap was the liquid sap under the ice sweet....it was so concentrated It seemed like someone boiled a bunch and put a teaser for me under the ice.

[40to1]

8993
This guy?
He provides security around my evaporator.
Doesn't help split wood or collect sap though....

Actually, the helmet and armour were made by Andrew Ainsworth - the guy would made the original 50 stormtrooper suits for Star Wars back in 1977. Says he based his molds on the originals. It pretty cool...

[SeanD]

Pretty cool is right.

May the thaw be with you,

Sean

[brikel]

This is my second year playing in the sugar bush. I was reading this post and am wondering how to know when to throw frozen sap away or when to keep it. I was told that when frozen sap thaws the sugar content is higher but I am not sure how to tell....no hydrometer.....could someone please explain this process to me. I have three gallons of frozen sap sitting in my kitchen trying to thaw as I type this.

[SmellsLikeSyrupNH]

I had about 20 gallons of sap frozen in my buckets form the past few weeks. On sunday with the slight warm up I went and dumped all the buckets and decided to boil what I had. The sweetness of the liquid under the ice was amazing...it was almost as though I had boiled down most of it and decided to freeze it, which of course I hadnt. I was so surprised as I hadnt noticed this at all last year. "Brikel"...just taste it, you will tell its a LOT sweeter....I didnt throw away any of the ice, I boiled it all because I hadd such a small amount.

[happy thoughts]

I was told that when frozen sap thaws the sugar content is higher but I am not sure how to tell.

That's not really true taken as you state it. Just want to make sure you understand what's being said. When sap freezes the early ice will be almost all water leaving liquid sap that has a higher concentration of sugar. Many of us will toss that ice, for instance when collecting buckets where some ice has formed.

If your sap is frozen solid, the sugars will be frozen with it, too. Thawing it will not increase the sugar content.

[brikel]

If your sap is frozen solid, the sugars will be frozen with it, too. Thawing it will not increase the sugar content.[/QUOTE]

so as the sap thaws out of a solid chunk does the sap become more concentrated or does it remain in it's original state.......... I understand that sap freezing will not raise the sugar content.....

[SmellsLikeSyrupNH]

With the small scale you are doing, Id just boil everything you get, no need to risk wasting even a little % of your sap.

The bigger operations have the luxury of getting lots of sap so they arent too concerned with tossing out the ice. My buckets were SOLID blocks of ice, except right under the ice was just a little bit of liquid gold.....so im sure the big blocks had sugar in them, but all of it didnt freeze.

[happy thoughts]

I honestly couldn't tell you though my thought would be that the concentration of sugars/water would be a gradient with the earliest forming ice containing the least sugar and so on as the rest of the sap freezes. Once it starts freezing it is no longer in it's original state and won't return to it's original state until completely thawed. It is much easier to toss the small amount of ice that forms early on fresh sap because you can be reasonably sure it is mostly water. To do it the other way around is not something we've really discussed here.Maybe someone else will have some better insight than me.

[happy thoughts]

Here's an article from a long time ago that appeared in Mother Earth News where someone made syrup almost entirely by freezing. Some of the info is wacky- do NOT plug tap holes as they suggest. It still makes interesting reading. By their process they calculated a loss of about 10% of the sugars. That could probably have been less if they didn't allow the sap to freeze as far as they did before removing ice.

http://www.motherearthnews.com/real-food/how-to-make-maple-syrup-at-home-zmaz74zhol.aspx

BTW- this is the same principle used in ice beers where freezing is used to increase alcohol content.

[BreezyHill]

Back when this last cold snap hit I drained our flue pan in to 4 stainless pails. As it froze I would skim the ice off. Couriousity got the best of me so I sampled the ice. Nothing.
A few nights later the finish pan had a skim of ice I sampled that and nothing. So I skimmed it off with a screener. The second night it of sub zero I started putting the ice of the flue pan into a large bulk mik strainer to allow any concentrate to drain that was trapped.
I got down to 10 gallons of concentrate that is in the 22% plus area and stopped skimming the finish pan when the ice had a slight flavor. The finish wont get more than a skim of ice and the flue product is fairly well frozen.

For me I just went with the taste method. No taste...good to throw out.

It will be interesting to boil with this level of concentrate and has a really good maple flavor.

The long range is looking good for a slow start and then a nice stretch so you may not get a chance to experiment with the icing much longer.

Ben

[Big_Eddy]

My son studying chemistry at University explained it to me last year - the post is on here somewhere. Essentially if the temperature is below 0 C but above -5C, the ice is 100% water. Once the temperature drops further, then the concentrated sugar solution will start to freeze into the ice.

So if it's just a few degrees below freezing and you have a layer of ice on the pail, toss it with no loss of sugars. Once the temperature frops below about -9C and more than half the pail freezes, then the sugars start to get tied up in the ice.

The reverse happens when thawing - if you have a tank of ice blocks that has thawed until the ice becomes filaments, the sugar has all come out, and you can dump the remaining ice. But you have to let them thaw enough that there are no hard blocks remaining to hold sugar. If you've ever had a tank freeze, you'll understand what I mean. The sugar solution thaws out first leaving the remaing ice as thin filaments that collapse / crumble when touched or shaken.

[ryebrye]

I had some 5 gallon jugs of sap freeze solid, so I brought them into my garage (it is insulated and stays around 40 degrees) and let them thaw for a little while (but not thaw completely).

When the sap that had frozen completely started to thaw, the liquid part was still way more concentrated than it was before. (1.4 brix before freezing, up to around 4.5 brix after freezing and letting it thaw a bit)

I am going to let the rest of it thaw and what the sugar content in the batch I didn't boil is out of curiosity (and also so I can reclaim my sap jugs so I can use them again) I expect the stuff that is still ice will be really low in sugar content (less than 0.5% probably)

[Geroldn]

I've been reading this forum and have learned a lot, this is my first post. I tapped in Northfield, VT on February 22-23 and had a small run - about 5" in the bottom of a 275 IBC tank ~30-40 gallons from 110 taps on gravity tubing. Not really enough to boil and it was the day before I went on vacation to Florida with the family. With 10 days of sub-zero weather, no runs and the tank is frozen solid. Wednesday night it was -20F at my house. Will this hurt the sap to sit frozen this long? Friday and Saturday cold nights and low 30s are predicted, maybe there will be a run. If the new sap goes into the tank on top of the old ice, what happens if these freezes also? Do I try to separate it and keep it liquid for boiling? or let it freeze, go skiing and plan to boil when the tank thaws once and for all.


2013 6 buckets, 6 sap sacks, concrete block fire pit in the woods and 20 gallon agway galvanized watering pan for boiling, produced 2 gallons of 'campfire' grade, Kubota L3200 for woods work

2014 2x4 WSE evaporator, 20x30 barn/sugar house, 110 taps on gravity tubing, 2 buckets, 1 sapsack

[happy thoughts]

Go skiing. The frozen sap will help keep any new sap you might get cold until you have enough to make boiling worth it. Tossing ice is optional. Freezing sap doesn't hurt it and helps preserve it.

[Ittiz]

The freeze-thaw method is how the drink Apple Jack is made from hard cider. The key to concentrating is freezing slowly to give the sugars time to migrate away from the forming ice crystals in the water.

My background is in laboratories and some of the equipment used in a lab gives me an idea for another trick people could try. In labs they use something called a sucrose gradient to separate chemicals/proteins by weight. Basically you take sugar water put your chemical/protein solution in it, usually you want it stained by some kind of dye so you can see it. Then you run it in a centrifuge which presses the sucrose and other materials down. They all layer nicely according to density. So the idea would be to centrifuge the sap and draw off the lighter water on the top and repeat until only syrup remains. Of course laboratory centrifuges can spin out of thousands of Gs. Obviously not a cheap thing to get, and the volumes are very tiny. However most people do have access to cheaper centrifuges in the form of clothes washers which can spin out at 300 to 400 Gs. So what you could do is use a washer to assist in freezing. The increased "gravity" in the centrifuge could assist the sugar in migrating away from the freezing water, making the whole process more efficient.

[Maplesapper]

Natures RO
If ice forms higher than -9 degrees celcius it contains zero sugar.
Colder than that it can contain sugars

[ryebrye]

Natures RO
If ice forms higher than -9 degrees celcius it contains zero sugar.
Colder than that it can contain sugars

For a small producer with a few taps and an unused adjustable chest freezer, would it be reasonable to turn on the freezer and set it to -9 C and store / freeze sap in there to concentrate it? The electricity would cost money, but it'd be cheaper than buying an RO.

I think I could fit about 4 or 5 5 gallon jugs in my freezer.

[Hebron Maple Dude]

Has anyone tried using a stock tank heater to thaw frozen sap in the tank?

[Deano686]

I've currently got a 180 gallon block of frozen sap in my 275 IBC tank. Our runs have been so small, that it's not enough to pump, truck and boil, and it freezes hard before the next run comes in. I have a 2nd tank plumbed in beside this tank for overflow. I was just looking at the 10 day, and am thinking it might be May before that giant ice chunk is thawed enough to boil!!! Mother nature is sure makin it a tough season so far. Best of luck to you all!!

[40to1]

I've wondered the same thing...
It's a lot of micromanaging sap, but if the evaporator isn't running and the freezer is, then every bit helps.

If you try it, let me know how it works...

[tcross]

I've tried the stock tank heater... it works but not that well! also, I believe they need to be in a liquid to work or they will shut themselves off? I had to heat the sap up with a space heater and chip away at the ice so a "puddle" formed! I wouldn't do it again! I'd just wait till some sap came in! it took 2 days for the stuff to melt and it didn't melt completely! I threw out a lot of ice!

[wall hollow]

Has anyone taken the early ice and thawed it and put it on a refractometer to see if there is any sugar at all
in the ice. If not I may do it at work during the season

[DoubleBrookMaple]

I went through this last year with my barrels. After reading this thread, and being reminded, I took some action today, on some ideas I had been hashing around. When we only handle small amounts we have the freezing sap issue. I had a spare heater ribbon laying around that I had removed from the roof a couple years ago. I have about 60 gallons in my tank, and will wait until after this cold snap to boil and test the heater out.
This is what I did with it, some insulation, and a lumber tarp. Just the bottom 18" are insulated. I will plug in the heater ribbon tomorrow after the overnight cold, and see what my sap temperature does. I have some wrapped around the valve.

***UPDATE***
Following day, after low of 4 deg sap temperature at 32 deg, daytime OAT 12 deg, after a couple hours sap temp 34 deg, before I knew it, later in the day sap temp went up to 42.
Final analysis...
I think this can not just keep from freezing, but plenty adequate to melt ice in the tank under very low Outside Air Temperatures. This is a 100 or 120 ft heater, and one could get by with much less. When I put it on my watt meter, it draws 12-1500.

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