alt Hacker NewsThe industrial version is produced in an autoclave, this allows precise control of curing, density and final mechanical resistance/insulation values. Hence, the name the material is best known by - AAC.
On the other hand, the video linked attributes too much credit and complexity to the foam manufacturing method, it can certainly be done with very primitive technology. Here are some dudes doing it in a developing country, it's very very basic, the foam generator is basically a steel wool sponge where pressurized air combine with water containing the foaming agent. They give out the complete recipe and details of their tools: