You can, but the milk must be boiled first. The culturing temperature of 42-45°C / 108-113°F is not high enough to kill harmful bacteria; on the contrary, it is a range in which they can also multiply. So boil raw milk, let it cool to culturing temperature, and then culture it. Raw-milk cheeses aged for a long time require controlled production conditions; the same level of safety cannot be ensured in a home kitchen.
The step most often skipped when making yogurt and cheese at home is heat-treating the milk before culturing it. The reason is easy to miss: a temperature around 45°C / 113°F, which is used for culturing, is not high enough to kill harmful bacteria. On the contrary, this range is a favorable environment for many microorganisms. In other words, if raw milk is cultured directly, it sits in a warm container for hours. That is why culturing does not count as a heat treatment for safety and cannot replace one.
The correct sequence therefore has two stages. First, boil the milk; after it comes to a boil, keep it there for a few more minutes. This step provides safety and directly contributes to the yogurt's texture, because heat changes the structure of milk proteins and helps form a firmer curd. This is also one reason yogurt made without boiling the milk turns out watery and loose. The longer the milk is boiled, the firmer the yogurt becomes, so some recipes deliberately extend the time.
The second stage is cooling, and there is no need to rush it. Let the milk stand until it drops into the culturing range of 42-45°C / 108-113°F. If milk is cultured above 50°C / 122°F, the culture dies and the yogurt will not set at all. Measure the temperature with a kitchen thermometer. If you do not have one, use the traditional method: if you can keep a clean little finger in the milk for about ten seconds, the temperature is suitable. The finger test varies from person to person; if you have a thermometer, use it every time.
Cheese is a little more complicated. Raw-milk cheeses aged for a long time are made around the world, but production takes place under controlled conditions, with defined aging periods and regular measurements. The same level of oversight cannot be established in a home kitchen. So if you make cheese at home, the milk should still be boiled and cooled; adjust the culturing temperature to the type of cheese. Homemade fresh cheeses should also be eaten promptly and not kept in the refrigerator for a long time. Packaged products state on the label which type of milk they are made from, so read that line when buying.
A few details make the process easier. As boiled milk cools, a skin forms on top; you can remove it for yogurt or leave it; both options work. Rinse containers and spoons with boiling water, because cleanliness matters when a mixture will sit in a warm environment throughout culturing. Wrap the culturing container to keep it warm and leave it completely undisturbed for four to eight hours. If the container is shaken during culturing, the curd breaks and the yogurt stays watery.
Comments (3)
Kaynatmadan mayalayan çok kişi tanıyorum, köyden gelen sütle. Buradaki gerekçe mantıklı ama eskiden nasıl sorun çıkmıyordu merak ediyorum. Belki de çıkıyordu ve kimse yediğiyle ilişkilendirmiyordu. Yine de artık kaynatıyorum, mayalanma süresi biraz uzuyor ama yoğurdum daha kararlı çıkıyor.
Kaynattıktan sonra kırk beş dereceye düşmesi ne kadar sürüyor, tencereyi soğuk suya oturtsam olur mu?
Oda sıcaklığında iki üç litre süt bir saati buluyor. Tencereyi soğuk suya oturtmak sakıncasız, yalnız arada karıştırın ki kenarlar ortadan daha çok soğumasın; termometre yoksa serçe parmak on saniye dayanıyorsa aralık tutmuş demektir.
Mayalama sıcaklığının zararlı bakteriler için de uygun aralık olması ürkütücü bir ayrıntıymış.