Ink and Equations

Real science, written as stories, poems, satire and speeches

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Ink and Equations

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Real science, written as stories, poems, satire and speeches.

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    Kitchen science

    Rajma, curd, idli and bread: the chemistry you eat every day.

    12345 5 pieces, best read in this order

    1. Stories The Rajma That Defeated My Grandmother A family trip to Leh, a pot of rajma that refuses to soften, and a pressure cooker that suddenly makes sense. The idea Water boils when its vapour pressure equals the pressure of the air above it, so at altitude, where air pressure is lower, it boils cooler; and because cooking reactions slow sharply as temperature drops, food takes far longer.
    2. Stories My Grandmother's Secret Is Bacteria Every night, Ammi saves one spoonful of curd. It takes a week away, a cold December windowsill and two ruined batches for anyone to ask why. The idea Curd sets because bacteria ferment the milk sugar lactose into lactic acid; as the pH falls towards 4.6, the casein proteins lose the negative charge that keeps them apart and link up into a gel.

      The next stop goes deeper into this one.

    3. Unpacked Meet the Bacteria Living in Your Curd A spoonful of old curd turned warm milk into new curd overnight, and a cold windowsill stopped it dead. Here's who was doing the work, and why they work best as a team. The idea Curd is made by lactic acid bacteria, often a partnership of Streptococcus thermophilus and Lactobacillus species, which split lactose and ferment it into lactic acid; the two help each other grow, take turns as the milk sours, and the acid they make keeps most harmful microbes out. Opens once you’ve read “My Grandmother's Secret Is Bacteria”
    4. Satire & Humour Bacteria Form Union, Demand Credit for Idli "Every night we work," said a spokesperson, one thousandth of a millimetre long. "Then somebody's mother gets all the compliments." The idea Idli batter rises because lactic acid bacteria such as Leuconostoc ferment the sugars from rice and urad dal into lactic acid and carbon dioxide; sticky substances from the dal trap the gas, and steaming sets the bubbles in place.
    5. Deep Dives Bread Is Held Up by Billions of Tiny Fungi Every loaf is a sponge full of gas made by living things. The holes are where the gas was, and the walls between them are made of a protein net you built with your hands. The idea Enzymes in flour break starch into sugars that yeast ferments into carbon dioxide and alcohol; kneading links two wheat proteins into an elastic gluten network that traps the gas, and in the oven the gas expands, the starch and proteins set, and the crust browns through the Maillard reaction.