Syrup boiling in bottle, long time after bottling

[raptorfan85]

I've been making Syrup for 5 years, and never seen this. I boiled in the evaporator until syrup and Drew off and filtered into a stainless pot. Came out to 5 gallons. Couple days later I brought to the house and got to density (about 15 minutes of boiling). Let that set for the night. Next day I brought it back up to just under boiling, did the secondary filtering, and bottled. The thermometer I have that's calibrated said 190. Bottled it all up. Constant temp throughout bottling. As I bottled I turned the glass bottles over in the case to seal the lids. I did the 33.8 oz (1000ml) bottles first. After I was done it was about 8 minutes since I bottled the 33.8s. I turned several back right side up and put them on the counter and they started boiling... They were not doing this upside down in the case. They continued to do this for almost 20 minutes. I took a video of it. Anyone seen this before?

https://youtu.be/z23ojDYWL2o

[maple flats]

If the cap was tight and they did not explode I submit it was an illusion. I suspect you saw air bubbles coming to the top. But it sure does look like it was boiling.

[ecolbeck]

That is fascinating. I have two ideas, both of which are wrong.

1. The ambient temperature in your kitchen is 219 deg.
2. Water will boil at room temperature if placed in a reduced pressure environment (a vacuum). As the bottle cools the pressure drops in the little air space at the top, and as a result the syrup boils.

[raptorfan85]

All the lids were sealed tight. Nothing exploded, although I was worried for a little while... Only thing I could think was that because of the vacuum they were boiling at a much lower temperature. Everything was filled to the top rim of the bottle.

[Bricklayer]

I kinda had stuff like that going on with my exact same bottles last year. Not as drastic but lots of bubbles in my syrup.
It ended up being faulty caps from CDL. They sent me new ones. They told me the black ones had the wrong material as a seal in them. Brown ones had the right material. Once I changed. They were fine.
Have you opened one by chance to see if they sealed properly ?
The white seal should stay on the bottle when plastic is removed and be dimpled down into bottle if sealed properly.
I also don’t fill bottles all the way to the extreme top anymore. Just to the bottom of the threads then cap goes on right away. I found if I go all the way to the top the glass get really hot and the plastic threads can’t be tightened all the way and pops off. Made a huge difference.
I also now only lay the bottles on their side for maybe 5 minutes then turn them up. Not sure if that makes a difference. But it might.
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[raptorfan85]

Just checked a couple. All the lids sealed tight. The white seal stayed on the bottles and were dimpled in so there was vacuum in the bottles. All seems correct...
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[TheNamelessPoet]

That is terrifying!

[Russell Lampron]

I'm going with the boiling under vacuum at a lower temperature theory. Did get any nitre because of it?

[SeanD]

The only time I've seen that is when I can homemade chicken stock with a pressure cooker. Those jars will continue to boil inside long after the jars have cooled in the canner then on the counter, so I think your vacuum/lower temp theory is correct. The mystery is why is is doing it here where you only went to 190 deg. Start by double-checking your thermometer in an ice bath then in boiling water.

[fisheatingbagel]

That is fascinating. I have two ideas, both of which are wrong.

1. The ambient temperature in your kitchen is 219 deg.
2. Water will boil at room temperature if placed in a reduced pressure environment (a vacuum). As the bottle cools the pressure drops in the little air space at the top, and as a result the syrup boils.

I vote for #2 - makes the most sense. The question is what creates the vacuum under this condition?

[ecolbeck]

There is a relationship between temperature and pressure in a closed system. This happens because gas molecules become more excited (move faster) as temperature increases. As they move faster they push harder against the sides of a container, creating higher pressure. The opposite will happen as temperature drops.

[BCPP]

The vacuum is created by the cooling syrup. As it cools it contracts to occupy less space causing a vacuum in the headspace. That's why mason jars pop when you open them, you are releasing the vacuum caused by the cooled contents. Draw a large enough vacuum and water (or syrup) will boil at low temperatures.

[raptorfan85]

The only time I've seen that is when I can homemade chicken stock with a pressure cooker. Those jars will continue to boil inside long after the jars have cooled in the canner then on the counter, so I think your vacuum/lower temp theory is correct. The mystery is why is is doing it here where you only went to 190 deg. Start by double-checking your thermometer in an ice bath then in boiling water.

I checked the thermometer last time I bottled with boiling water. I guess it's possible it could have moved. I'll recheck it again tonight when I get home.

[raptorfan85]

I'm going with the boiling under vacuum at a lower temperature theory. Did get any nitre because of it?

No new niter formed. I checked them this morning and all were still Crystal clear.

[Super Sapper]

I think filling to the very top helped create more vacuum without the small air pocket to buffer it a little.