Techniques – #C – Controlled Caramelisation & Controllled Evaporation
Onions/ tomatoes form the base for a huge range of recipes. So we desperately needed a hack to eliminate the sauteeing step which tied generations of cooks to the stove for hours. We achieved it with the Controlled caramelisation technique.
There are three key methods of creating flavour, without adding herbs/ spices. All involve browning.
1. The Maillard reaction: When proteins are heated, the amino acids and sugars combine with each other. You see this in fried chicken/ browned meats/ breads. This reaction happens only when the temperature crosses 140 degrees. This reaction is responsible for the intense taste and flavour of froed/ browned foods. Till OPOS, it was not possible to replicate this reaction inside a pressure cooker as the temperature inside a pressurised cooker never crosses 120 degrees, the boiling point of water at 15psi.
So, we first needed to figure out a way to achieve 140 degrees, before we could make the Maillard reaction happen. We managed to do it with the controlled caramelisation technique.
2. Pyrolysis: When sugars are heated, they decompose. You see this in caramelised onions/ caramel.
3. Enzymatic browning: Natural enzymes in fruits/ vegetables react with oxygen to produce browning. You see this in chopped potato/ apples turning brown. This is undesirable in case of fruit/ vegetables, but is essential in coffee/ tea/ chocolate.
We can control the browning by balancing the quantity of food, by preventing burning, by varying the cut size & by the use of the right fat. Getting the steps and proportions right took multiple trials, all of which have been documented. Here’s an example, illustrated with onions.
We realised the key to onion caramelisation is pyrolysis. The logic is simple – we had to heat onions so that the complex sugars in them break down into simpler sugars. This browns them, makes them sweeter and much more flavourful. This heating needs to stop just short of burning and needs to be unsupervised. Pyrolysis (Fire – seperate) is a technique used in the chemical industry to make charcoal & activated carbon, among other things. The technique calls for heating organic matter in a sealed container till it starts breaking down.
Controlled caramelisation made possible soft, caramelised, flavourful onions & tomatoes, the base for many recipes, in a single step, in under 5 minutes of unsupervised cooking. The same principle was later extended to cover most vegetables, meats and seafood.
Controlled caramelisation led us to the next step – Controlled evaporation, which led to Ghee, Halwas and Jams, covered in the next chapter.
In OPOS, we cook blind. As a second step is prohibited, we cannot fine tune the consistency/ texture as we cook. So the key is to understand how various foodstuffs behave and figure out ways to cook them at one shot.
In some recipes, the goal is to ensure all or most of the water is evaporated. This just means that we need to balance the cooking time with the desired water content. The amount of water that needs to be evaporated away depends on the recipe being cooked.
In some recipes, we need to stop cooking when most of the water is evaporated. In halwas, thokkus and jams, most water needs to be cooked out, but some water needs to remain to ensure the fudge like consistency.
In some recipes, all water needs to be evaporated away. While cooking ghee, we need to ensure all water is evaporated, to ensure the ghee has a long life.
In some recipes, we need to extend cooking time beyond the point when all the water from the bottom layer has been evaporated, to produce a desired charring.
The Controlled Evaporation technique is used in all these cases. We go by the time between whistles as a key indicator to judge the amount of water remaining inside the pot. We also go by sound clues to judge the consistency (in case of ghee) and by the smell as key indicators.
As long as water remains in the pot (either directly or in the food stuff you add), the whistling happens at steady intervals. When all water in the pot evaporates away, the time taken per whistle becomes longer and longer. This indicates there is not enough water to create fresh steam. This is the point at which you should stop cooking in case of ghee. You can follow the same principle for cooking thokkus/ curry bases, though consistency is not as crucial here as in case of ghee.
Controlled evaporation deskilled and demystified making ghee. It turned a laborious, hit or miss process into a precise technique. The same principle also opened up a world of thokkus and later, halwas. We tried to first understand ghee before attempting it.
Ghee is more aromatic than butter because of the browning reactions. Plain butter is white. Ghee varies from golden to shades of brown. The caramelisation reactions are responsible for the colour and flavour of ghee.
Traditionally Ghee is prepared by simmering butter (or cream). The butter is added to a large saucepan over a low flame and melted. The layer of foam that appears on the surface is periodically skimmed away. The butter is simmered and allowed to bubble. The sides are scraped off periodically. This process takes anywhere from an hour to many hours. With experience, the cook can judge the colour, flavour and decides to stop heating. Though most ghee is plain, additives are occasionally used for clarifying it or flavouring it. We had to condense this process into one step, while controlling the colour, texture and flavour