I made ikan bilis soup stock with my thermal pot yesterday, and the results floored my helper, Joy. She raised an eyebrow at me when I told her that we would make soup by bringing the water to a boil and then inserting the pot (on the right) into the insulated sleeve (on the left).
We took out the inner pot and boiled the water again after 2 hours (to replenish the heat) and then insulated the pot for another 3 hours. The 2nd boiling took all of 3 minutes on the induction stove top because of the residual heat still in the soup. The resulting soup was flavourful. The meat and cartilage on the knucklebone fell quite off. The soy beans and ikan bilis were fat and soggy. Sceptical Joy was very impressed. She hadn't believed me when I said that one could boil soup without a constant fire.
For those readers who wish to buy a similar pot, I got mine for $90 (instead of $200 to $300) because it is not a well-known brand. Mine is also not a vacuum design. I was afraid that a vacuum design might be fragile. If you drop it and a crack introduces air into the vacuum, the whole sleeve is useless. And if I remember right, the vacuum design is more expensive generally. My insulation sleeve has a thick layer of insulation material instead.
Perhaps the insulation material is less effective than a vacuum but if you don't mind taking the pot out to boil the water after 2 hours, you'll still get a decent pot of full-bodied soup stock.
I am looking forward to making brown rice and barley porridge for breakfast. Just heat and insulate before bedtime and voilà, warm and fragrant porridge in the morning!! I hope it'll work though because I ain't getting up in the middle of the night to boil the porridge twice!! Anyhow, I'll let you all know when I've tried.