Sometimes, the ideas backing modern kitchen conveniences can be traced back hundreds of years. This is part of what makes modern kitchen design so fascinating; oftentimes, we’re revisiting ideas our ancestors had laid out well before us, proving the desire to innovate and make our lives easier is one ingrained within our very DNA. Today, we’d like to take a good look a thoroughly modern kitchen innovation that can trace its roots back to the Medieval age; that of the Vacuum Cooker.
Your mind mind immediately leaps to a Pressure Cooker upon hearing the name, and though the principals are somewhat similar, the Vacuum Cooker is an entirely different beast. A Vacuum Cooker comes in two parts; an inner pot, and an outer one. The contents you wish to cook are placed within the inner pot, which is then heated to cooking temperature. Once it reaches cooking temperature, it is placed within the outer pot and sealed shut.
What the outer pot does at this point is act like a Flask (and it is often called as such); it reduces heat loss to the absolute bare minimum, meaning the contents of the inner pot continue to cook without any further fuel or energy needing to be expended to do so. This keeps meat tender, reduces food waste/burning significantly, and keeps the flavour firmly locked in the dish. Dishes which require a long period of Braising or Simmering are perfect for the Vacuum Cooker as well, and as a result they are highly favoured by Cantonese cooks- in fact, when the Vacuum Cooker was introduced to the US, they sold in large numbers primarily in Asian communities.
The principal has existed a lot longer then the modern equivalent, however; as prior mentioned, the idea backing the Vacuum Cooker can be traced back to the Medieval practise of Haybox cooking. The practise is more or less identical; a large, earthenware pot containing food would be heated to cooking temperature, and then place either in a larger pot, a reasonably sized box, or even a hole in the ground, which would have been insulated using hay, dry leaves, and even moss in some cases, before being covered.
For safety reasons, it is absolutely essential that whatever you are cooking is heated to an appropriate temperature. For many foods this rests at most anywhere above 60°C, but certain foods- including a variety of beans such as fava beans and kidney beans- contain a toxic pathogen by the name of that must be boiled for 10 minutes at 100°C to be reduced to safe levels. Bringing such foods to a rolling boil for a brief period before placing it in the flask should ensure the food is cooked safely. It’s also worth noting that most any food can be cooked using a Vacuum Cooker; even baked goods, such as Bread or Cake, can be cooked in one so long as they are slightly submerged in water.
This spirit of erstwhile innovation is what business like ours were built on, and we can’t deny a certain sense of pride seeing said innovations become wildly adopted as the years roll by!