This may be the wrong sort of blog on which to ask this, but…
Our family has a “Therm au Rouge” (that site has the best images) wine-warming sleeve – one of those things you buy for a Christmas present out of desperation. It wraps round a bottle of wine and, after “clicking” a small square of metal inside the pouch by bending it, an exothermic reation is initiated which warms the wine. The reaction spreads out from the “clicker” and the clear liquid in the sleeve turns into a white solid, emitting heat in the process.
The reaction is reversible; when it’s complete, you can boil the pouch in water for ten minutes to reverse it and turn the liquid back to clear. The instructions say it’ll work at least 100 times before you should replace it.
I’ve searched the web but I can’t find out:
- What is the chemical reaction involved?
- How does the clicker which initiates it work?
Our family is having a Christmas “discussion” about this so if anyone has any ideas, I’d love to hear them…