Formula preparation seems simple — measure powder, add water, shake. But the details matter enormously for safety. Incorrectly concentrated formula can harm your baby's developing kidneys. Contaminated formula can cause serious gut infections. Water that is not adequately treated can carry pathogens. Here is how to do it right every time.
The Water: Starting Right
In India, the water source matters significantly. Municipal tap water quality varies across cities and seasons. The safest approach for preparing infant formula is to use water that has been boiled and then cooled to between 70 and 75 degrees Celsius. Boiling kills most bacterial contamination, and preparing formula at 70 degrees rather than body temperature is recommended by WHO because it kills the Cronobacter bacteria that can contaminate powdered formula itself.
Do not use water that has been sitting in the kettle for hours — reboil or use freshly boiled water. Filtered water from household filters reduces chemical contamination but does not kill bacteria unless the filter is specifically designed for this. Boiling is the most reliable method. Bottled mineral water is not appropriate for formula preparation as it contains mineral levels unsuitable for infants.
Step-by-Step Preparation
First, wash hands thoroughly with soap for at least 20 seconds. Clean the surface where you will prepare the feed. Boil fresh water and cool to 70 degrees Celsius — this takes approximately 30 minutes after a full boil. Add the correct amount of boiled water to a sterilised bottle first — always water first, then powder, so the powder displaces water rather than the other way around, which gives a more consistent concentration.
Add the correct number of level scoops of formula using the scoop provided with your specific formula. Do not use a different brand's scoop as sizes vary. Level off each scoop with a clean, dry knife or the leveller provided — do not pack the powder down. Never add extra scoops thinking more is better — this can cause hypernatraemia (dangerously high blood sodium) in young babies.
Cap the bottle and gently swirl (do not shake vigorously) until the powder is fully dissolved. Cool the made formula to feeding temperature by placing the bottle in a bowl of cold water or holding under cold running water. Test on your inner wrist — should feel neutral to slightly warm, not hot.
Storage
Made-up formula should be used within 2 hours at room temperature (Indian room temperatures are high and bacteria multiply quickly). If refrigerated immediately, made-up formula can be stored for up to 24 hours. Never reheat formula in a microwave — it creates hot spots that can burn your baby's mouth even if the outside feels cool. Warm in a bottle warmer or bowl of warm water. Discard any leftover formula after a feed — do not save and reheat.