You can use any kind of milk, including whole milk, 2 percent, 1 percent, nonfat, pasteurized, homogenized, organic, raw, diluted evaporated, dry powdered, cow, goat, soybean, and more. UHP, or ultra-high pasteurized milk, is processed to a higher temperature, which breaks down some of the proteins that the bacteria need to make the milk into yogurt. Some have reported difficulties in making yogurt from UHP.
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 (unflavored) yogurt. Be certain it has “active cultures” on the label. Yogurt cultures die over time so try and find the freshest yogurt that has a tart flavor, but no added flavors or other additives. Taste various plain yogurts before you get started. You will find that different kinds taste a bit different. Use one you like for your own starter. The different flavors are due to other bacteria than the two main bacteria needed to create yogurt. Alternatively, instead of using existing yogurt, use freeze-dried bacteria cultures (available in specialty stores or online), which are more reliable as a starter. In a pinch, you can use a flavored yogurt, but the taste of the resulting cultured yogurt will not be exactly the same as using plain yogurt.
You could also use Ball jars if you are so inclined, but these are not necessary.
Keep the yogurt still during incubation. Jiggling won’t ruin it, but it makes it take a lot longer to incubate. After seven hours, you’ll have a custard-like texture, a cheesy odor, and possibly some greenish liquid on top. This is exactly what you want. The longer you let it sit beyond seven hours, the thicker and tangier it will become.
You could also use the pilot light in your oven, or preheat the oven to the desired temperature, turn it off, and then leave the oven light on to maintain the temperature. Turn your oven on periodically, as needed to maintain the temperature. This method is tricky; make sure that it doesn’t get too hot. Or, you could use the bread proof setting if your oven has one. Other methods include using a food dehydrator, a rice cooker’s warm setting, a heating pad set to low, or a crock pot set on its lowest setting. If you have none of these things, you could use a sunny window or a car in the sun. Note that light exposure may degrade the nutrition in the milk. It is best to maintained the temperature below 120ºF (49ºC), don’t allow it to go below 90ºF (32ºC); blood temp to 110ºF (43ºC) is optimal. Additionally, you could place the container of yogurt in warm water in a sink, large bowl, or small picnic cooler.
The untimed, resistance heated yogurt makers are generally popular because of their low cost. They tend to be less expensive because they are designed with no control over the temperatures needed to properly incubate the yogurt bacterial culture(s) in the dairy product used. They are designed for average home temperatures but higher or lower environmental temperatures can change the time it takes to make the yogurt and quality of the yogurt produced. They generally come with smaller cups and must be used repeatedly throughout each week to provide for daily consumption of yogurt. With larger families, they can become impractical because of the time it takes to make a given quantity of yogurt. The temperature regulating yogurt makers are more expensive as they require more electronic components to be able to maintain temperature settings. There are two types within this category: Another type has an (optimal) factory temperature setting which is maintained regardless of environment. You cannot adjust the temperature setting in this type. There are yogurt makers which combine some of the features found in some of the above categories. For example, one yogurt maker provides a factory set regulated temperature with a time - display and cut-off feature. This unit is capable of producing a quality yogurt result in as little as 2 hours as the temperature setting is well above popular home yogurt culturing temperatures. It allows the user to use more than cup-sized containers, although they are supplied in several sizes with the yogurt maker. You can use a gallon size container or 4 wide-mouth quart containers to make as much as a gallon at a time. However, with the taller jars, either a larger cover may be needed or towels may be used to cover the gap between the supplied cover and bottom (heating and control) unit.
Yogurt makers which allow the user to set the amount of time the yogurt maker applies heat to the containers. While this time setting may be handy should you need to leave the yogurt maker unattended, it is suggested the user remain in the general area (home) so that if anything should go wrong (like the unit failing to shut off) - granted a rare occurrence - may deal with the situation.
Many commercial yogurts include a thickening agent, such as pectin, starch, gum, or gelatin. Don’t be surprised or concerned if your homemade yogurt has a somewhat thinner consistency without these thickeners. Putting the yogurt in the freezer to cool it before to moving it to the refrigerator will result in a smoother consistency. You can also stir or shake in the lumps.
