(Alternate with desired quantity)
- 1 quart/litre cream, whole or low-fat milk
- ¼ cup starter (plain yogurt with live culture)*
- ⅓ cup nonfat dry milk powder
- 2 to 4 tablespoons honey or sugar
Pasteurization for Non-Commercial Raw Milk
Heat water in the bottom section of a double boiler and pour milk into the top section. Cover the milk and heat to 74°c while stirring constantly to maintain uniform heating. Cool immediately by setting the top section of the double boiler in ice water or cold running water. Store pasteurized milk in the refrigerator in clean containers until ready to make yogurt.
- Combine ingredients and heat.
Milk must be heated so that the proteins bind together instead of forming curds and whey. Do not substitute this heating step for pasteurization.
Place cold, pasteurized milk in the top of a double boiler or in a saucepan and stir in nonfat dry milk powder for additional solids. (Adding nonfat dry milk to heated milk will cause some milk proteins to coagulate and form strings.)
- Add sugar or honey if a sweeter, less tart yogurt is desired.
- For a thick, firm yoghurt soften 1 teaspoon unflavored gelatin in a little milk for 5 minutes. Add this to the milk and nonfat dry milk mixture before cooking.
- Heat milk to 85°c (or up to 93°c for a firmer consistency) over low heat, stirring gently. Hold temperature at 85° to 93°c for 10 minutes for thinner yoghurt or up to 20 minutes for thicker yoghurt. Do not boil. If not using a double boiler, stir constantly to avoid scorching.
- Cool and add starter
Place the top of the double boiler (or sauce-pan) in cold water to cool milk rapidly to 44°-46°c. Remove one cup of the warm milk and blend it with the yogurt starter culture in a small bowl. Add this mixture to the rest of the warm milk. The temperature of the mixture should now be 43°-44°c.
Pour immediately into clean, sterilized, warm container(s); cover and place in prepared incubator. Close the incubator and incubate for 4-7 hours at 43°c. Yoghurt should set firm when the proper acid level is achieved (pH 4.6). Incubating yogurt for several hours after the yogurt has set will produce more acidity. This will result in a more tart or acidic flavor and eventually cause the whey to separate.
Rapid cooling stops the development of acid. Yoghurt will keep for about 10 to 21 days if held in the refrigerator at 4°c or lower. Additions to the yoghurt may reduce the shelf life. Discard any yoghurt with visible signs of microbial growth or any odors other than the acidic smell of fresh yoghurt.