Wednesday, August 19, 2009

Cách làm sữa chua

Công thức này hơi bị tây, làm không thành công lắm. Sau đó đi Nha Trang học được cuả chị Thu và Thảo công thức ta hơn: trộn 1 lít sưã tươi không đường với 1 lon sữa bò pha cùng 2 lon nước sôi. Quy trình thì cũng giống dưới đây thôi.

Sau đó mẹ mang công thức đến Nike làm, tiếng vang rực rỡ (:

  • 1 quart milk (any kind)
  • 1/4 to 1/2 cup non-fat dry milk (optional)
  • 2 tablespoons existing yogurt with live cultures (or you can use freeze-dried bacteria instead)
  1. Heat milk to 185F (85C). Using two pots that fit inside one another, create a double boiler or water jacket effect. This will prevent your milk from burning, and you should only have to stir it occasionally. If you cannot do this, and must heat the milk directly, be sure to monitor it constantly, stirring all the while. If you do not have a thermometer, 185F (85C) is the temperature at which milk starts to froth.
  2. Cool the milk to 110F(43C). The best way to achieve this is with a cold water bath. This will quickly and evenly lower the temperature, and requires only occasional stirring. If cooling at room temperature or in the refrigerator, you must stir more frequently. Don't proceed until the milk is below 120F(49C), and don't allow it to go below 90F (32C). 110F (43C) is optimal.
  3. Warm the starter. Let the starter yogurt sit at room temperature while you are waiting for the milk to cool. This will prevent it from being too cold when you add it in.
  4. Add nonfat dry milk, if desired. Adding about 1/4 cup to 1/2 cup nonfat dry milk at this time will increase the nutritional content of the yogurt. The yogurt will also thicken more easily. This is especially helpful if you are using nonfat milk.
  5. Add the starter. Add 2 tablespoons of the existing yogurt, or add the freeze-dried bacteria.
  6. Put the mixture in containers. Pour your milk into a clean container or containers. Cover each one tightly with a lid or plastic wrap.
  7. Allow the yogurt bacteria to incubate. Keep the yogurt warm and still to encourage bacteria growth, while keeping the temperature as close to 100F (38C) as possible. An oven with a pilot light is one option; see Tips for others. After seven hours you will have a custard-like texture, a cheesy odor, and possible some greenish liquid on top. This is exactly what you want. The longer you let it sit beyond seven hours, the thicker and more tangy it will become.
  8. Refrigerate the yogurt. Place the yogurt in your fridge for several hours before serving. It will keep for 1-2 weeks. If you are going to use some of it as starter, use it within 5-7 days, so that the bacteria still have growing power. Whey, a thin yellow liquid, will form on the top. You can pour it off or stir it in before eating your yogurt.
  9. Add optional flavorings. Experiment until you develop a flavor that your taste buds fancy.
  10. Use yogurt from this batch as starter for the next batch.
  • Your first batch is always the hardest.
  • You can use any kind of milk, including whole milk, 2%, 1%, nonfat, pasteurized, homogenized, organic, raw, diluted evaporated, dry powdered, cow, goat, soybean, and more.
  • All yogurt needs "good" bacteria. The easiest way to add this is to use existing yogurt. The first time you make your own yogurt, use store-bought plain yogurt. Be certain it has "active cultures" on the label.
  • Alternatively, instead of existing yogurt you can use freeze-dried bacteria cultures (available in specialty stores), which are more reliable as a starter.
  • Using a double boiler makes it easier to control the temperature.
  • If your oven doesn't have a pilot light but does have an oven light, preheating the oven to the desired temperature, turning it off, and then leaving the oven light on to maintain the temperature.
  • Another method is to turn your oven on and then off again periodically. Be careful that it doesn't get too hot.
  • To check the oven temperature, you can put your candy thermometer in a bowl of water inside the oven.
  • Other methods for keeping the yogurt warm are: hot water in a sink, a stove burner, a crock-pot, a warming tray, a large thermos, a heating pad, a sunny window, in your car on a sunny day, etc. Just use your thermometer and best judgment.
  • The longer the mixture incubates, the thicker and more tangy the yogurt will be.
  • Putting your yogurt in the freezer to cool it before to moving it to the refrigerator will result in a smoother consistency.
  • Canned pie filling, jams, maple syrups, and ice-cream fudges are good flavorings.
  • For a delicious appetizer, use your yogurt to make labneh cheese.
  • Using a yogurt maker makes the incubation process a lot easier. It automatically maintains the proper temperature and you don't need to use the oven or watch the temperature. Most come with individual glass jars to put the yogurt in.
  • Some food dehydrators, such as Ronco induction type, can be used as yogurt makers too. Read the instructions in the manual.
  • Watch your temperatures. Don't let the milk get too hot or too cold.
  • Old starter won't grow yogurt.
  • If your yogurt smells, tastes, or looks strange, don't eat it. Try again with a new batch.
  • Get a second opinion on the taste of your yogurt, to make sure it's okay.
  • Keep the yogurt still during incubation. Jiggling won't ruin it, but it makes it take a lot longer.
Things You'll Need
  • Pot
  • Metal spoon
  • Candy thermometer
  • Double boiler (Optional)
  • Containers with lid
  • Oven
  • Refrigerator

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