Glass jars at 40 below zero?

[buck3m]

I know that glass jars can be put in a freezer without breaking, because I've tried it. I've got about 30 gallons in glass jars that I want to put in a shed in Alaska for a few months. It could get -40 or even colder. Can I be sure they won't break if the density is accurate?

[Bucket Head]

I know for a fact syrup does'nt freeze solid at 10 degrees becuase my father has some in his freezer and thats what the temp. is in it. The water portion will be frozen no more or no less wether its 10 degrees or -40 degrees, right? The sugar portion would probably get a lot stiffer as the temp. decreased, but I would'nt think its going to expand (like frozen water in pipes) and bother the jars. I guess the question is wether theres a below-zero temp. that would solidify the remaining sugar content. Do you know the manufacturer of the jars? Can you contact them and ask them what they think the limits are on their containers and contents?

Steve

[buck3m]

I guess the question is wether theres a below-zero temp. that would solidify the remaining sugar content.
Steve

I agree. I found this: The freezing point of syrup decreases depending on how much sugar is in the syrup. A 50% sucrose solution freezes at -7.6 degrees C (18.32 degrees F). (Of course maple syrup is about 66%)

Read more: http://wiki.answers.com/Q/What_is_the_freezing_point_of_syrup#ixzz1c2gCQqct

If that is accurate it makes me wonder about 40 below!

In theory, maple syrup does not freeze provided that it has the right Brix density (66%).
http://www.siropderable.ca/Afficher.aspx?page=60&langue=en

Lots of sources say it can survive freezer temps, but I'm still not sure if it will survive 40 below in glass.

[Flat47]

What about making a tundra cooler? I used them to keep fresh food refridgerated while doing remote work up off of the haul road. Peel back the upper layer right above the permafrost and then dig out what you can. Use boxes or plywood to make a box to store your stuff in. Then flop the top layer back over your box. During the summer months food stays nice and cool. I would think that this would help moderate some of the extreme temps in the winter months. Don't forget to mark where your cooler is...people have lost track of their stuff before.

[buck3m]

What about making a tundra cooler?

That's a very good idea but the ground is already froze and it would have to be pretty big.

I have a 1/2 pint glass bottle sitting out at 2 deg. F. right now and it isn't frozen.

[buck3m]

Dr Perkins said it would freeze somewhere above 40 below.

Everyone seems to agree that pure maple syrup at the proper density will not freeze solid at home freezer temps, however.

[buck3m]

I've done some experimenting. Right now I have two glass containers of maple syrup outside, 1 "salad dressing" style 1/2 pint, and one pint canning jar. It is currently 40 below zero (F. and C. coincide at this temperature.)

I found that crystals started forming at 20 below F.
There was still a little liquid visible at -26.
It was all crystals at -30.
It looks just about identical at -40.

It has definitely expanded some, but has not broken the glass. Looks to me that if the containers had been filled right to the top they might have broken.

Undoubtedly there are numerous variables; container type, exact brix, amount of invert sugars, but that's what I've observed to date.

[buck3m]

Looks to me like it not only is not expanding any more, but more likely contracting a bit.

[Goggleeye]

We used to freeze goat's milk in glass jars. We would never fill them to the neck, we always left some room. What we found out is that most canning jars will take several hard freezes with the pressure of expansion, but after too many times, they would break.

[buck3m]

We used to freeze goat's milk in glass jars. We would never fill them to the neck, we always left some room. What we found out is that most canning jars will take several hard freezes with the pressure of expansion, but after too many times, they would break.

That's interesting. Theoretically, maple syrup should expand much less because there is less water in it and obviously it must get much colder to freeze. This morning it is -51 and my two test jars still look fine, but frozen solid.