Intro: Homemade Cheese Science
-Milk normally consists mostly water and also contains proteins like casein and whey proteins,fat,lactose and other minerals.
-Their are diffrent types of cheeses in world and some cheeses can be easily made whereas some require ripening for several weeks or months to acheive flavour
-Despite several cheeses in world most of them are made with similar processes.
-One of the main step in cheese making is to remove water from milk.
-After removing water and whey proteins finally cheese will be left with casein,fat and lactose.
-Here are steps in making cheese and basic science involved
Step 1: CURDLING MILK
-By curdling milk we are seperating whey proteins and water.Here cheese ingredients sit together and form lumps in milk.As a result we see curds floating around in liquid
-Watery phase left over is called whey which is poured off and we are left with curd
-Take milk in vessel and bring to boil
Step 2: HOW MILK IS CURDLED?
-When milk starts boiling add 2tbsp lemon juice for one litre milk.you can see milk starts curdling
-Proteins in milk are normally suspended in colloidal solution,which means smaller protein molecules float freely and independently.
-Normally these protein molecules repel each other,allowing them to float independently without clumping
-But when the pH of the solution changes,they can attract each other and form clumps.
-When pH drops due to addition of an acid the protein casein molecules attract each other become curdles floating in solution of translucent whey.This reaction appears more fast at warm temperature than cold temperature.
-Therefore temperature also plays an important role for reaction to occur because when we add lemonjuice or vinegar to cold milk it takes some time for milk to curdle whereas with hot milk immediate curdling occurs
-Fresh cheese like ricotta or paneer are prepared by heating milk at designated temperature and then an acid is added.Solid proteins are then strained from liquid whey and shaped in to rounded cheese
Step 3: STRAINING THE CURD
-Seperating whey from curd is done using cheese cloth which keeps curd intact and removes whey
-place cheese cloth on colander and pour the curdled milk on it.Entire whey gets removed through straining
-Rinse the intact curd on cheese cloth with water to remove lemon smell.
Step 4: SQUEEZING EXCESS WATER
-Next step is to bring together the ends of cheese cloth and squeeze excess water from it
Step 5: PRESSING
- Flatten the cheese with hands and place on plate and put some heavy weight on it and leave for 4 hours
-After 4 hours we can see block of cheese which can be sliced to cubes and enjoyed in all dishes
-In some cases this step is skipped when making ricotta or some soft and moist cheese.However in most cases the cheese has to be pressed where excess water is removed by pressing and tightening curd texture
-pressing makes cheese more solid sturdy product
Runner Up in the
Explore Science Contest 2017