We theorised that a fixed valve pressure cooker could be used to cook and store food for days, without refrigeration. When food is heated to over 120 degrees, most microorganisms get killed and food gets sterilised. This sterilisation is not possible by just boiling because some bacteria have evolved to survive boiling.

Boiling water is present in nature (in hot springs, for instance). Some microorganisms have evolved to survive even in boiling water. However, no organism has evolved to survive 120 degrees, the temperature inside a pressurised pot. Because this temperature is not found anywhere in nature. So no organisms have evolved to adapt to this temperature.

Cooking at 120 degrees kills most bacteria like Salmonella, Campylobacter, Lysteria and E.Coli, responsible for most food poisoning. Prolonged cooking sterilises everything so completely, that the sterilised items can be used even for medical procedures. The autoclave used in hospitals for sterilisation is nothing but a pressure cooker.

As the food gets sterilised, we theorised it should remain fresh as long as no contaminants get into it from outside. This is possible in a pot with a fixed safety valve, which maintains its seal even after cooking. A pot with a floating safety valve loses its seal after its pressure drops. So it cannot be used for sterile storage. After repeated trials we found any food cooked in a fixed valve pot would remain perfectly fresh for nearly a week, as long as it remains undisturbed.

When proposed, this technique almost ripped the group apart. We have a deep rooted taboo against stored food. Many believed we have gone too far by promoting such weird, non-traditional ideas. Many believed we were risking food poisoning.

A few bold members tried it out and found it worked, and worked brilliantly. At the peak of Chennai summer, coconut curries (which are notorious for spoilage) were cooked and served after 3 days, to their unsuspecting families.

By repeated tests with various foodstuffs, we now have confirmed that ANY food indeed stays fresh for nearly a week, irrespective of the outside temperature, if cooked and sealed properly. This means the equipment should be in good condition, the whistle should not be removed after cooking and the pot should not be disturbed. Theoretically, it should behave like canned food and remain fresh forever.

Unfortunately the seal is not designed for this kind of use. So it maintains its integrity only for a short time (around a week). After a week, microorganisms are able find their way in and spoilage starts.

Using this technique, we can now convert a fixed valve pressure cooker to a short term canning device and store cooked food for nearly a week without refrigeration. This very long steeping has an added bonus of infusing flavours deep into food. Any cooked food, sour or not, can now be stored for days, with no compromise in taste, texture or flavour. Curries/ Biriyani/ Dals etc can all be stored this way, and they actually get better with storage!

Members have experimented with storing pongal for 4 days, coconut curries for over 5 days and rice for over a week. When food was later tested in a food lab, we found that it was no different from fresh cooked food.

The amount of time food would stay fresh depends on the condition of your pot, the cooking time and pressure reached. If your pot is in good shape and has an intact seal, your food should remain fresh for nearly a week. Some members took unopened pots with them during long train journeys. They reported food stays fresh for over 2 days.

This is so counter- intuitive to a nation obsessed with fresh food. Many Indians still refuse to eat food over a few hours old. We still have a lot of taboo attached to eating stored food, especially food left outside. This cultural conditioning is the biggest stumbling block preventing people trying out this technique of flavour infusion and food storage.

We used this sterilisation technique during the 2015 Chennai floods, when many of us were cut off from drinking water supplies for over a week. We advocated the sterilisation of water using this technique. It went viral and was used by many to tide over the crisis.

This technique can be extended to sterilise almost anything baby bottles, cutlery etc. Members have used a larger pot as a supercharged dishwasher. They loaded small cups and spoons into the pot with a bit of dishwash and ‘cooked’ to completely sterilise them in minutes. Some used it to clean silver jewellery and pooja items.

But using it as a technique for short term food storage still remains controversial.Though repeated trials have confirmed it works well, our cultural conditioning is still too strong! Understand it well before attempting it.