How to make curd at home in 30 minutes (Easy home experiment)

A sim­i­lar ex­per­i­ment is in­clud­ed in the “Chem­istry of drinks” set from the MEL Chem­istry sub­scrip­tion.
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In this ex­per­i­ment, you’ll find out how to make curd at home from just two in­gre­di­ents.

Safe­ty pre­cau­tions
Ob­serve safe­ty rules when work­ing with heat­ing de­vices

Warn­ing! Only un­der adults su­per­vi­sion.

Reagents and equip­ment:
* 1 liter of cow’s milk;
* 5% cal­ci­um chlo­ride so­lu­tion (15 ml);
* saucepan;
* spat­u­la;
* gauze;
* hot plate;
* glass con­tain­er.

Step-by-step in­struc­tions
Pour milk into a saucepan and heat to a tem­per­a­ture of 40 С (104 F). Then add the cal­ci­um chlo­ride so­lu­tion and heat for 20 min­utes. Keep stir­ring the mix­ture con­stant­ly and don’t bring it to the boil. Watch the milk cur­dle.

Pro­cess­es de­scrip­tion
Cow’s milk is a dis­per­sion sys­tem–a wa­ter emul­sion con­sist­ing of drops of fats, sug­ars and pro­teins bond­ed with min­er­al com­po­nents. A liter of milk con­tains 30-35 g of pro­teins. When a co­ag­u­lant is added (for ex­am­ple, cal­ci­um chlo­ride so­lu­tion), the bal­ance in the sys­tem is dis­rupt­ed and the pro­teins cur­dle (co­ag­u­late). So we get curd. In­ci­den­tal­ly, in Que­be­cois cui­sine, this prod­uct is called cail­lé and is con­sid­ered to be a na­tion­al dish.