The supply of milk, especially during war times, has represented a problem that should not be underestimated for many years, which is why during the nineteenth century, the process of producing condensed milk was perfected in the United States, an invention which was originally due to the Frenchman Nicolas Appert. Condensed milk, in fact, due to the absence of humidity, can be stored for longer, without the fear of it oxidising. Condensed milk, thanks to rapid boiling, manages not to oxidize, as happens in the case of toffee.