Homemade Yogurt
1. Bring one quart (or liter) of milk to the simmer stage, stirring often to prevent scorching and sticking to the bottom of the pan, and remove from heat.
2. Cover and cool until the milk has reached room temperature or below (may be placed in refrigerator to speed cooling). It is very important that you allow the temperature to drop sufficiently or you will kill the bacterial culture you are now ready to introduce.
3. Remove about 1/2 cup of the cooled milk and make a paste by mixing it with 1/4 cup of good quality commercial yogurt. The commercial yogurt you use should be unflavored and unsweetened. Buy one that contains only milk or milk solids and bacterial culture, if possible. It is usually unnecessary to buy yogurt culture separately since commercial yogurt is very satisfactory to use as a starter. If you find it impossible to buy commercial yogurt that contains only milk and bacterial culture, then you are advised to buy yogurt culture (“starter”) separately. After removing what is needed, return the container of commercial yogurt to the coldest part of the refrigerator for it to be used as a starter for the next batch of homemade yogurt.
Saving some yogurt from a previous batch of homemade yogurt to use to start a new batch is not as satisfactory as using commercial yogurt as a “starter” each time. Manufacturers of commercial yogurt make every effort to use “lively” bacterial strains and extremely large numbers of bacteria in the manufacturing process. The conditions of home refrigeration most often do not promote the survival of yogurt bacteria to the same degree as the conditions maintained by the commercial producers of yogurt. Homemade yogurt, made by using some from the last batch as a “starter”, often fails to solidify (coagulate) properly due to insufficient live bacteria to properly convert the milk sugar.
4. Mix the paste with the remainder of the cooled milk and stir thoroughly.
5. Pour milk into any appropriate sized container, cover, and let stand FOR AT LEAST 24 HOURS at 100 to 110 degrees Fahrenheit. (38 to 43 degrees Centigrade.) If you forget to remove it after 24 hours, and the fermentation goes on longer, all the better. Under no circumstances should the fermentation time be decreased to less than 24 hours. This fermentation time should supersede any other instructions that may accompany a commercial yogurt maker. ommercial yogurt maker.
The source of heat used during the 24 hour fermentation is critical. It is very important to get the temperature correct at 100 to 110 F (38 to 43 C) before you proceed with the fermentation. Too high a temperature will kill the bacterial culture and will prevent the proper “digestion” (conversion) of lactose. Too low a temperature will prevent activation of the bacterial enzymes and will result in incomplete “digestion” of the lactose.
A thermos type of yogurt maker may NOT be satisfactory for this long fermentation period inasmuch as the hot water surrounding the thermos will not stay warm. Commercial electric yogurt makers control the temperature perfectly but the amount of yogurt that can be made at one time is limited.
The ideal source of heat is a large electric warming tray. If it has a temperature-regulating dial, use a thermometer to set the dial properly (a mouth thermometer is satisfactory). If the warming tray does not have a dial to control the temperature, cover the surface of the tray with a thickness of metal (such as a metal cake rack), or FIRE-RESISTANT material (such as a Teflon treated ironing board cover). Then allow the tray to remain on for about five minutes before placing the thermometer on the surface to determine the temperature. If too warm, use a thicker piece of metal or material. By using the large surface of the electric warming tray, a gallon of yogurt can be made at one time in two plastic or ceramic half gallon containers. An electric crock-pot (set to low) or heating pad, both checked for temperature, may be used.
Some people use their ovens; the pilot in a gas oven usually keeps the temperature in the oven within the correct range. If using the oven of an electric stove, change the oven light to a 60-watt bulb. Turning on the oven light (with a 60-watt bulb) should create enough warmth to make yogurt but always check the temperature with a thermometer first. Sometimes the oven door must be propped ajar with a little stick to achieve the correct temperature range. CAUTION: upon completion of yogurt fermentation, replace regular oven bulb.
6. Allow the yogurt to remain on the heat for a minimum of 24 hours to insure that all lactose is completely “digested.” Remove from heat gently, pour into smaller containers if desired, and refrigerate.
While this yogurt may not be as thick as commercial yogurt, it will be a true yogurt since virtually all of the lactose has been digested by the bacterial culture and further lactose digestion will not be required by intestinal cells.
For more information on yogurt makers and cultures, visit www.breakingtheviciouscycle.org.
