Cream puff made with choux pastry is one of the popular dishes in my baking course. I have taught it to several batches of students. After over three decades of teaching cooking, I thought I knew all the dishes I taught like the back of my hand. So I was least prepared for the surprise, the choux pastry mixture sprung on me in one of my classes.

Choux pastry is made by boiling water with some butter and a pinch of salt and tipping the flour into it at one go and stirring the mixture till it forms a smooth soft lump. Then eggs are beaten into it and the dough turns rich and shiny, ready to be piped and baked.

Coming back to the day when I was demonstrating the technique of making Choux pastry in class, the mixture just would not thicken in the boiling water to form the paste. I added extra flour. It did not help. This was the first time in my long career that I was facing a complete and utter flop in a class. After considerable struggle, I had no option but to admit to my students that I had no clue as to why this particular recipe, which worked fine all these years, had failed on that day.

As soon as I got back from my institute, I tried the recipe at home and it was perfect! I refrigerated the pastry and baked the puffs next day in the class and asked the students to just follow the recipe and tell me how they fared. No one had any problems. Over the next few months I often wondered why the flour had not coagulated on that particular day.

The mystery was solved when I read an article by a professional chef where she wrote about her experience with a simple custard made with corn flour, which refused to thicken and embarrassed her during a demonstration. She found the reason after speaking to some food scientists. Incredibly, it turned out, the culprit was the water. Certain salts that may be present in water, prevent the starch from coagulating! The day my choux pastry failed, I had used canned drinking water and the salts in canned water change from brand to brand. I then remembered many other incidences when water played an important role in cooking.

I once went to watch Hardy Chang, a celebrated Chinese chef demonstrate the fascinating art of making noodles with his bare hands. I watched mesmerized as his deft hands patted, folded and pulled a lump of dough till they fell into thin, uniform noodles. Later when he spoke to me, he said he could not take any chances with the ingredients used for these noodles and even the water was imported from Singapore. "Why water?" I had thought and wondered if he was just being too fussy. But now I know better. I remember on one occasion, my string hopper (Idiyappam) dough separating into a powdery mass in a cloudy liquid instead of turning into a soft smooth ball.

While working with electric rice cookers, I learned that some salts in water cause excessive bubbling when cooking rice, causing water to overflow from the rice cooker. I also happened to notice that turmeric turns an orange red color if the cooking water has alkaline salts. Ever wondered why some Dhoklas are orange in colour? Sometimes, a little turmeric is added to the besan in Dhokla . Lime juice or citric acid and cooking soda are added to Dhokla batter. If the soda is not fully neutralized by the acid, the turmeric in the mixture turns orange in color.

Who would think that the simplest of ingredients can make so much difference to a dish?

CHANDRI BHAT