Yogurt is a fermented milk product in which a mixed culture of Lactobacillus bulgaricus (or occasionally L. acidophilus) and Streptococcus thermophilus which produce lactic acid during fermentation. This lowers the pH and makes it tart. The partial digestion of the milk when these bacteria ferment milk makes yogurt easily digestible.
In addition, these bacteria will help settle GI upset including that which follows oral antibiotic therapy by replenishing non-pathogenic flora of the gastrointestinal tract.
Several factors are crucial for successful yogurt making:
- Good sterile technique (i.e., proper cleansing and heat treatment of glassware)
- Proper incubation temperature. Lactobacillus is killed if exposed to temperatures over 55oC, and does not grow well below 37oC. We will use a temperature on the high side of its preferred growth temperature so that most pathogens will be strongly inhibited from growing.
- Protection of the starter from contamination. Do not open the starter (either Dannon Plain yogurt, or 4 oz starter from the previous yogurt batch) until you are ready to make the next batch.
Yogurt is preserved by its acidity which inhibits the growth of spoilage bacteria. With lids intact, this yogurt will keep at least a month or two in the refrigerator. After that time, a layer of non-pathogenic white mold may form on the top. After this is removed, the yogurt is still suitable for cooking.
Baked goods will rise well when yogurt is used due its acidity. Use it as part or all of the liquid in cakes, waffles, pancakes and muffins, and cut down on the amount of baking powder.
Yogurt is an excellent dish by itself, but is valuable in its many other uses
½ gallon milk
½ cup Dannon plain yogurt (use a fresh culture for starter)
double boiler (or heavy pot) with lid, capacity 2 ½ qt
two qt. bottles with lids, sterilized in boiling water
an 8 oz jar with lid, very clean and sterile.
candy thermometer, reading range = 40 to 90oC (100 to 200 oF)
1 Styrofoam cooler
Heat milk to 85-90oC in double boiler (185-195 oF). If using a heavy pot, stir frequently to prevent sticking. Keep covered.
Remove from fire, place covered pot in pan of clean cool water until stirred milk is very close to 55oC (130oF).
Stir up yogurt starter with a clean fork, add to 55o C milk, stir thoroughly, (temp should drop to 50 oC (122 o F) or just below). Pour still warm mixture into the three bottles, plus the smaller 8 oz jar. Cover immediately with the sterile lids.
Place filled bottles in cooler, add enough 50oC (122 oF) water so that bottles are surrounded, but the water is well below the lid rims. The starter jar will have to be placed on a support to keep its lid above the water.
Do not disturb the yogurt and it will be finished in 3 hrs, provided the temperature does not drop below 40 oC (104 oF). Refrigerate until needed.
For more firm yogurt, add 2 Tbl powdered milk to the ½ gallon of milk prior to heating. Either whole or skimmed milk may be used, but whole milk makes richer yogurt.
YOGURT HAS MANY USES:
My favorite uses of yogurt include:
In place of sour cream. Add dollops:
- to baked potatoes,
- on rice dishes,
- on bowls of soup (especially lamb stew, chilli or borscht).
- with hot chili (works as a fire extinguisher too!)
- In cucumber-yogurt soup (fabulous summer dish)
- As a liquid in soda-raised breads, waffles and pancakes
- To make Laban , a Lebanese soft cheese, (easy yogurt cheese) can be made by hanging yogurt in a clean cloth, permitting the whey to drip into a bowl. Add salt to taste. It is delicious served with pulverized spearmint and olive oil as a dip.
- as a starter for cheese
- as a starter for yogurt (see above for how to do this)
- Diluted and slightly salted to make ayran (EYE-ron), a refreshing Turkish cool drink.
Check any Middle Eastern cookbook for a variety of uses.