Mason Jar Internal Temp

Does anybody know how long it takes for the air in a mason jar to come to the same temp as the water bath?

As long as the jar is fully submerged its contained air temperature should take the same length of time as the other contents to achieve temperature equilibrium.

You will notice bubbles coming from the jar if you sealed it just finger tight. This is due to the air in the jar warming and expanding. When removed from the bath the air cools and creates a seal. Not as good as when canning under pressure but it does show that the air got hot.

Yes, the jar would be fully submerged. So, your saying that the air wouldn’t be “up to temp” until the end of the cooking cycle?

So your saying that the air is the same temp as the water as soon as it starts leaving the jar?

It starts to bubble as soon as the internal pressure from heat is great enough for the air to force its way by the seal. SOme of this is due to the expansion of what you are cooking and some of it due to temperature rise. As the air temperature rises during the cook bubbling increases. At home we have no way of easily monitoring the air temperature as a function of time.

Not at all Doc.
However you must realize you haven’t revealed sufficient pertinent project details to receive the precise answer you seek instead of discussing bubbles.

Perhaps we could be more helpful if you disclosed the purpose of your inquiry. The why often leads to the what.

Air temperature in the jar depends on the total mass of the contents, cooking temperature, and length of time at cooking temperature.

Being a Doc you likely know the temperature of the jar’s contents never equals water bath temperature, but over sufficient time approaches it to close enough status.
Does that help?

Otherwise it might be useful to construct a time and temperature chart to monitor the rise in temperature and the approximate internal air temperature of the jar.

This is beginning to sound like all hot air.

The project is to decarboxylate CBD in hemp material. I would like to do it in a mason jar rather than a plastic bag due to losing materials sticking to the plastic bag after decarboxylation. Also, the bags seem very fragile after being in 200º F water for two hours, so I’d feel better about doing the infusion in glass to avoid a potential bag leak. I know time and temp in an oven to do this in a mason jar, but wasn’t sure if I could use same times and temps if using sous vide.

Most organic chemistry is beyond the knowledge base of this cook. However, infusions i understand, but you are attempting to process your material at a higher temperature than is usually sustained with SV cooking and lower than most decarboxylation reactions.

You might want to use an oven with a baking steel or bricks beneath the jars for temperature stabilization.