Thawing frozen Sap

[TheNamelessPoet]

So I am going to be boiling probably 1x a week so I have been freezing my sap, the little that has run anyway.

I have a couple 1 gallon jugs. I did not think about the thawing of them.

Should I just take them out of the freezer 24 hours or so before and leave them in my darkish basement (its about 50-60 degrees down there I think) to thaw so I can boil them on my grill? I will be boiling hopefully Sunday so should I take them out Saturday, or tomorrow night?

I suppose I could put the entire jug in a pan on the stove on low to get it up to a warm temp so I can pour it out. I think I am going to use Tuppaware or find containers that are tapered with the opeing on top that is the widist point. Then I can just drop the block into the pan when I start boiling (along with some already melted sap of course so I do not burn the pan).

Ah the joys of 1st time :rolleyes:lol

[30AcreWoods]

I would just pull them out a day ahead like you suggested. Let them thaw in your basement. There will still be some ice the next day...so how about dumping the liquid into your pan and cutting away the plastic and dropping the frozen sap into the pan with the liquid. That way you don't burn the pan. The sweet will melt first...so if there is just a very little ice left, that's primarily water and you don't have to bother boiling it. That will save you time...

[bowhunter]

Freezing is a good way to remove part of the water. Let them sit out and thaw overnight. Boil the liquid and throw the remaining ice away. The ice phase will contain almost no sugar.

[maple flats]

What bowhunter said. I suggest you drain the liquid when the ice is about 1/3 of the total and toss the ice. This is often referred to "the poor man's RO. 24 hrs at cool cellar temps might not thaw that much, it might take 36-48 hrs, you will need to try to find the thaw time needed.

[jrgagne99]

I disagree. If the jugs are frozen solid, it is likely that the sweet is concentrated in the center. It won't be melted and liberated until the shell of less-sweet ice around the exterior goes away. But the sweet may still be in solid form, depending on the rate at which the melting occurs around the outside. It might be difficult to tell. I would probably melt and then boil it all.

My take is that throwing away ice as a poor-mans RO works well for buckets, but only when there is some liquid (sweet) yet to be frozen. Once the whole chunk is froze solid, it's much more difficult to separate the sweet from the not sweet.

[tpathoulas]

I agree with Jgagne99. You are essentially making a maple flavored popsicle. When you eat a popsicle you get the same amount of sugary flavor on the last bit as the first lick. If totally frozen I think you should cook it all. The issue then becomes the energy it takes to thaw and get to boiling. It takes a great deal of wood and or propane. A few years ago we had a nice sap run but we also had a long warm spell and couldn't get the sap cooked before the warm up. We had an empty chest freezer so we froze about 200+ gallons of sap. We then had a nice sap run after a cool down. We had a lot of sap to cook and the frozen sap took a tremendous amount of preheating(propane) and cooking(wood). We cooked from 8:30 AM on a Sunday and finished at about 1:15 AM on Tuesday. I have a 4'x4' homemade evaporator that holds 100 gallons. We tried to keep it half full while cooking. The frozen sap made the process very slow. I highly recommend, thawing in a way to maintain the sap without bacteria, Fridge, or outside on the north side of a building if the temps are reasonably cool.
Best of luck!

[TheNamelessPoet]

I appreciate all the help and the advice! When I was at the Local MASPC last month I spoke with one of the speakers there after the meeting about the best way to start my setup and I asked about it. Never dawned on me to ask them about what to do with it once frozen lol.

One thing my grandfather said, was exactly what you guys said, which was just throw out the ice, it's a poor man's RO. I brought it up in the meeting and they said there was a study done by (I THINK) Cornell where they tested the liquid, AND the ice individually and got almost the same concentration when they melted down the ice. I am having trouble finding the study itself, but admittedly I haven't looked for it until this moment.

I was thinking I might take 1 gallon out Friday and 1 on Saturday and see what happens... Hey, this year is my 1st year so its all about testing things right?

[hansel]

I like to do this and take advantage of any good overnight freezes when I have sap. I let sap freeze solid in 4 or 5 gallon buckets. Defrost it in basement or outside if it's warm enough. Once 1/3 has defrosted(keep 1.3-1.7 gallons) I toss the rest. Can refreeze that concentrate, defrost again and toss half. Pretty much all of the sugar will be in that and you get rid of 83%.

[TheNamelessPoet]

Interesting hos much conflicting information there is! One thing I need to get is a sap hydrometer. I think I might do my own experiments on it once I do!

I do have to say, it would be AWESOME if I could do what you said @hansel, because man, that would save me the $ of getting an RO!

@30acrewoods, I would do that, but I don't want to waste my containers. I had about 10-15 total that I had gotten from buying water (when I ran my well dry. oops) and that a few people gave me. If I start cutting into them, I will run out pretty quickly.

I have a list of things I am going to get for next year, and one is a large storage tank, and some type of bucket I can freeze that the block of ice will come out of. Then I can drop those INTO the large tank in the basement to keep it cool for up to a week.

I saw this in someone else's thread (I don't remember their name off the top of my head unfortunately, but THANKS to them :-p

[bowhunter]

Guys this is based on science not just someone's opinion. The sugar concentrates in the liquid phase and the water concentrates in the ice phase as the sap either freezes or thaws. Dave Klish is right you do need to have a significant part of it in the liquid phase to get a good separation and it's not a perfect separation. But if you remove the ice from your buckets you can easily save yourself some boiling or RO time without wasting much sugar. Native Americans used this method to concentrate sap for thousands of years. I've had buckets concentrate from from less than 2% sugar to over 3.5% sugar by removing the ice from the partially frozen bucket. I routinely walk through my sugar bush as the buckets thaw and remove the floating ice.

[maple flats]

Namelesspoet, find that study, I don't believe both the liquid and the ice once thawed had the same sugar%. I never heard of any study showing that.

[bill m]

The sweet will not be frozen in the middle, it will be in the bottom of the container. There will be some sugar in the ice. The closer to the top the less sugar there will be.

[DrTimPerkins]

Stinson and Willits in the Maple Syrup Digest Vol. 2, No. 2. 1963. http://www.maplesyrupdigest.org/?m=196302

The summary is below:

Summary
1. Do not discard ice from partially frozen or melted sap. The value of sugar lost with the ice exceeds the gain from lower oil consumption.
2. Dipping frozen sap in plain water or fresh sap has no advantage.
3. Discarding centrifuged ice which has been crushed or rinsed is advantageous. However, this procedure would not be practical due to the high cost of centrifuging.
4. Discarding the ice from partially frozen sap appears economical only under unusual condition wherein an evaporator house could not process all of the sap supply or a maple farmer could not haul all of his sap run. Under these rarely encountered circumstances it would be advantageous to process only the liquid portion of the mixture since syrup solids are greater in the liquid phase.

Keep in mind that this was done when oil was so cheap that houses had very little insulation because it was cheaper to burn fuel.

A more recent smaller study is at: https://digitalcommons.csbsju.edu/cgi/viewcontent.cgi?article=1102&context=elce_cscday , although this has some methodological issues (length of time over which it was conducted and spoilage/consumption of sugar by microbes).

That said, I think it can be a bit more complicated than that depending upon fuel and cost as well as time available. The ice that forms (especially at first) will be mostly water with very little sugar. As more of the liquid freezes, some sugar will get entrained into the ice. In general, if the bucket is 1/4 or less ice, I'd toss it, although you will lose a SMALL amount of sugar. If more ice, keep it. As a youngster sugaring with my grandfather/father/uncle, we'd toss the ice in the bucket or let the strainer in the gathering tank accumulate it and then scoop out the ice from that once it had drained some.

[tgormley358]

While I’ve mostly tossed the nice from buckets and tanks in recent years on the advice of this forum, I’m thinking this year of keeping more of it to help keep sap cool as temps rise. The only downside seems to be it takes up room in the bucket or tank that might be needed for a strong sap flow. I suppose as it melts it will dilute the sugar content of the liquid back to normal,
But my small RO will take care of that.

[Ed R]

Since rock solid frozen sap is such a pain to deal with afterwards, I always try to look ahead and keep it boiled in on the front end. It messes up your tank capacity and bucket capacity to much for too long, plus you risk busting up your buckets if they are full. I always toss partially frozen sap.