Mason jars breaking in freezer?

[Run Forest Run!]

From what I know, syrup at the proper density will not freeze solid. It becomes more like the consistency of molasses when placed in a freezer. I want to store my extra syrup in the freezer in mason jars. Has anyone ever had one of them crack in the freezer due to expansion of the syrup? I always fill my jars and bottles into the neck to ensure that they are shelf stable at room temperature, but is that too high for bottles destined for the freezer? This is a mistake I don't want to make. Anyone have any advice and/or experience with a freezer disaster?

[Downstate]

The Ball mason jars I use have a fill line for freezing. But I have never tried freezing syrup in them so try at your own risk.

[Ausable]

Karen - I have never stored maple syrup in the freezer ----- But - my hero - Rink Mann who wrote "Backyard Sugarin" said - that He stored his maple syrup in the freezer in coffee cans with the lids on and he had done it for years. If I was using canning jars I would flip the lid - seal side up - and fill on the light side to allow for expansion. Someone that has actually done it will chime in.

[sparkplug]

Hi Karen, we have frozen most of our syrup as it will keep for years that way. We do ours in 2 liter plastic jugs and it will not freeze solid as you stated. In mason jars , i would think if you left some head room for some expansion you should be ok. How about testing 1 jar and put it in a plastic margerine container incase.

[John c]

I have put quart size mason jars of syrup in the freezer with no issues. You are correct in saying that proper density syrup will not "freeze", however a few of my jars from another batch was light and they did "freeze", but they still didn't break. Maybe I just got lucky!

[Run Forest Run!]

Thanks for the thoughts so far everyone. John c, how much headspace did you have in your mason jars? I'm afraid if I fill them high enough them for a proper heat seal and then decide to store those ones in the freezer they'll be too full. I suppose I could always underfill some bottles and only ever store them in the freezer.

Sparkplug, I could try one and put a plastic margarine container underneath as that would catch any leaks, but then there's the possibility of glass shards that wouldn't be addressed.....ouch.

Mike, FYI, I re-read Rink's book every year just before tapping time. It gets you in the mood for sugarin'. :D

Maybe I just waaay underfill my glass containers, or freeze in plastic only? I've got hundreds of glass jars here from all of my preserving, that's why I was thinking about the glass route. Plus, there's no chance of any flavour transfer from glass.

[John c]

About a half inch, but if your density is correct I don't think it should matter.

[Galena]

Hey Karen

The people who taught me sugaring have about 5 deep freezers full of frozen maple syrup, they've been doing it that way for gawd knows how long. They leave a fairly generous amount of headspace, like about to where the Mason jar starts to narrow at the top. So that's about 1/2 inch below where the lid grooves are. Hope this helps.

[bushmoose]

I have always froze my syrup in glass jars and never have a had any breakage. I put them it carboard boxes, each jar surrounded with cardboard so there's no contact between them. I also use glass liquor bottles for my own personal supply (much easier for pouring) and have never had any issue what-so-ever.

[Run Forest Run!]

Thanks for the reply Galena. Very helpful. Bushmoose, how much headroom did you leave in your glass jars? About an inch?

[MustardSeedMum]

I've put 1L glass jars into the freezer. Haven't had any breakage. Filled to where the neck starts...if that makes sense. Like others have said, syrup at the proper density doesn't freeze solid. I had a couple of jars which I filled with syrup purchased from st.jacob's a few years ago....they were totally overcooked...so now I have these gigantic sugar crystals at the bottom. But no broken glass. You should be good.

[Run Forest Run!]

Thanks MSM. I know exactly what you mean about the neck of the bottle.

[1arch]

In 2014 I bottled directly from the evaprator into two quart mason jars which I intended to finish filter however didn't get them done... About 15 gallons in these two quart jars sat on the shelf in the sugar house through this past winter. Multiple times while out in the sugar bush cutting fire wood around <10 degrees F. About 30% of the jars took on an opaque color which I'm sure they were freezing. I was a bit concerned about them however I didn't disturb them at all. I blended these all together this syrup season and finish filtered and bottled them. No jars were cracked and density was very close after the blend.

[buck3m]

Quoting from an earlier post I did:

"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. [Nothing changed down to 51 below zero.]

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."

On thing to consider is syrup shrinks considerably as it cools from bottling/canning, then expands again as it freezes so those factors are partially offset. I have stored many gallons at extreme temps now. Personally I would not hesitate to put sealed syrup in the freezer if the density is right.

[Run Forest Run!]

All of this is very helpful. As long as I leave decent headroom as an insurance policy everything will be good. :)

[Big_Eddy]

At the other end of the spectrum, if you have crystals in the bottom of a syrup jar, do NOT put the jar in the microwave to heat it up and dissolve the crystals. I guarantee the jar will break. I have seen it happen more times than I can count. After the syrup is gone, put some warm water in the jar, put it back in the fridge and WAIT. Those crystals took a while to form, they dissolve at the same rate. Patience!!!!

Likewise, if you store your syrup in the freezer, make sure you bring it out early and warm it up gradually before you need it. No microwaves. Glass jars do not like thermal shock.

[Run Forest Run!]

At the other end of the spectrum, if you have crystals in the bottom of a syrup jar, do NOT put the jar in the microwave to heat it up and dissolve the crystals. I guarantee the jar will break.

Big Eddy, do you mean when there is no syrup left in the jar and only crystals stuck on the bottom or do you mean when there is still syrup in the bottle too?

[Big_Eddy]

Syrup crystallizes in the jar or bottle.
:) Kids eat the syrup. Not a drop left.
:rolleyes: Kids add 1/2 cup of water to the jar and placed in microwave to heat up
:mad: Glass breaks
:cry: Dad cleans sticky mess from microwave - AGAIN!!

[Run Forest Run!]

Oh! Thanks for telling me Big Eddy. I've done that several times and obviously have been fortunate so far. I'll NEVER do it again!

[MapleMark753]

Hi, thought I'd chime in too! We use mason/ball jars in pint and quart size for about 1/3 of our syrup, and freeze lots just for our family. Got probably 30 in the freezer now, about the same as past years. Fill em pretty full too, say within a quarter inch of the top. Knock on wood, but have never had any break at any time in the freezer. That's just our experience... Not a scientist here, but while it may expand slightly in the freezer, maple syrup in a typical home freezer never gets cold enough at standard density to actually freeze. I guess that means the freezing point of maple syrup is much lower than a standard freezer gets.
take care, Mark

[Run Forest Run!]

Thanks for posting Mark.