The Case of the Exploding Maple Syrup in (1) Gallon Glass Container

I thought I knew what caused a (1) gallon glass container of maple syrup to explore last June but a friend is convinced it was another cause. Here's what happened.

Last June I bought (2) gallons of maple syrup in glass containers. One I immediately put in the refrigerator and started using and the other in an entrance closet on the tile floor. I noticed that both gallons were filled right to the top with no air space but didn't realize what that could mean.

A few weeks later with the ambience temperature in the house at 78 degrees F, we heard an explosion and checked the closet. The gallon glass container had exploded into many pieces and much of the syrup was on the floor.

I have been thinking that the syrup was cold-packed at a temperature lower than 78 degrees F and that the 78 degrees F temp on the floor of our closet was enough to cause the syrup to expand and cause the explosion. A friend believes that this temperature change would not have caused the syrup to explode and that the syrup was likely NOT boiled down enough and continued to "ferment" causing it to expand in the glass gallon container I received it in.

I would appreciate thoughts on whether temperature changes and/or continued fermentation or some other reason explains the explosion.

OrangeAgain,
You may never know for sure. But you can rule out the dog knocking it over!
A lot of syrup is packed in glass, so that is not a new thing.

The syrup could be a issue as far as the density. Yes if to low of a density it would ferment and could cause some expansion, But not sure it would break the bottle?? Maybe someone else has examples of that. So if you have some syrup from the other container the density can be checked, Assuming it was processed at the same time? Any batch code info on the container?

As a note canning temp for finished syrup should be at 180 F. Most cold canning was done in the old days like 50 years ago. But if cold canned it should have been noted to keep it refrigerated as soon as you brought it home.

Not sure this helps?
What a mess with syrup all over!
Regards,
Chris

It generally isn't permitted to sell cold-packed syrup in retail containers unless they are marked to be refrigerated. The difference in temperature expansion is probably rather minimal, so I'd lean towards cold-packed at low-density. Did it smell "fruity" or "yeasty" when you cleaned it up?

If you have access to a syrup refractometer, check the density in the remaining bottle.

Alternatively, you might have had a hairline crack in the bottle from handling that even a minor change in temperature might have caused to break. Was it a new retail container, or something you or the producer cleaned and re-used?

Dr. Perkins; Thanks for your thoughts.

If the glass gallon jugs were "canned" when the syrup was cold and filled up to the very top, would an increase to 78 degrees F in our closet be enough to cause the syrup to expand enough to explode the jug?

Quote:

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Originally Posted by Sugarmaker

OrangeAgain,
You may never know for sure. But you can rule out the dog knocking it over!
A lot of syrup is packed in glass, so that is not a new thing.

The syrup could be a issue as far as the density. Yes if to low of a density it would ferment and could cause some expansion, But not sure it would break the bottle?? Maybe someone else has examples of that. So if you have some syrup from the other container the density can be checked, Assuming it was processed at the same time? Any batch code info on the container?

As a note canning temp for finished syrup should be at 180 F. Most cold canning was done in the old days like 50 years ago. But if cold canned it should have been noted to keep it refrigerated as soon as you brought it home.

Not sure this helps?
What a mess with syrup all over!
Regards,
Chris

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Quote:

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Originally Posted by OrangeAgain

If the glass gallon jugs were "canned" when the syrup was cold and filled up to the very top, would an increase to 78 degrees F in our closet be enough to cause the syrup to expand enough to explode the jug?

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How cold was it when canned? Realistically...probably doesn't matter a lot. I think it unlikely that it broke due to thermal expansion...unless the syrup density was very low or there was a flaw in the glass. Keep in mind that the glass would have also thermally expanded.

I would still say to try and get the remaining syrup you have from the other container checked for density. Couple other details. Does the syrup have the name of the producer? If so you could tell them what happend and see if they have any other issues like this.
Couple of other things? Does the syrup seem very runny and thin? Or did you happen to see large sugar crystals in the bottom of either of the jugs?
Regards,
Chris

I sounds like you had two issues that are probably the cause.

First I don't think that 78* would be enough to cause the glass to break unless there was a defect in the glass.

Second the jug was full to the top which to me would indicate that the jug was filled cold. When you put hot syrup into glass and fill the jug to the top the syrup will contract when it cools and leave an air gap at the top of the bottle.

Third under density syrup will ferment if not refrigerated and build a lot of pressure. I have seen square plastic jugs expand to the where they are almost round. When the cap is removed from one of those jugs the pressure will hiss out so you have to remove them with caution.

I can tell you from experience that the bottles were packaged cold and to the top and room temperature of 78 degrees would break the bottles as there’s no room for expansion. Ran out of containers one day last season,so went back down next day to can out remaining syrup out of the filter tank. Fairly cold day,so syrup was coming out slowly,so I proceeded to do other things while syrup was dribbling into the 1 gallon glass jug. Came back to find syrup overflowing on the jug. Put the cap on with intentions of repacking into smaller containers after heating the syrup up to 180. Got busy that night with other things,found a sticky mess in the morning as the bottle had broken due to expansion from being in a warmer environment