Mixing the Milk and Starter
Incubating the Bacteria
Adding the Finishing Touches
Sure, it’s easy to stroll down the supermarket aisle and throw a cup of yogurt into your cart, but have you ever been tempted to make yogurt in your own kitchen? Yogurt made with good bacteria benefits your digestion, improves immunity and lessens food allergies. Follow these steps to learn how to make your own yogurt.
1 quart (946 mL) milk (any kind but if you use “ultra-high pasteurized” or “UHP” or “UHT” then you can skip step one, as the milk has already been heated to this temperature before the pack was sealed)
1/4 to 1/2 cup non-fat dry milk (optional)
1 tablespoons white sugar to feed the bacteria
pinch salt (optional)
2 tablespoons existing yogurt with live cultures (or you can use freeze-dried bacteria instead)
Mixing the Milk and Starter
1. Heat the milk to 185ºF (85ºC). Using two large pots that fit inside one another, create a double boiler. 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 of the while. If you do not have a thermometer, 185ºF (85ºC) is the temperature at which milk starts to froth. It is highly recommended that you obtain a thermometer in the range of 100 – 212ºF, especially if you plan to make yogurt on an ongoing basis.
- 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.
2. Cool the milk to 110ºF (43ºC). The best way to do 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 it more frequently. Don’t proceed until the milk is below 120ºF (49ºC), and don’t allow it to go below 90ºF (32ºC); 110ºF (43ºC) is optimal.
3. Warm the starter. The starter is the bacteria that you add to the milk, which in turn cultivates more bacteria–bacteria that is necessary for the creation of yogurt. Let the starter yogurt sit at room temperature while you’re waiting for the milk to cool. This will prevent it from being too cold when you add it in.
- 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.
4. Add nonfat, reduced fat, or whole dehydrated milk, if desired. Adding about 1/4 cup to 1/2 cup 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’re using nonfat milk.
5. Add the starter to the milk. Add 2 tablespoons of the existing yogurt, or add the freeze-dried bacteria. Stir with a whisk or use a blender (such as a stick blender) to evenly distribute the bacteria throughout the milk. If you still have stringy ropes you may be heating your milk too fast or too long (scalding). Use a double boiler in that case, or at least stir regularly and check temperature with a thermometer. At high altitudes this can be more of a problem.
Incubating the Bacteria
- Put the mixture in containers. Pour the milk into a clean container or containers. Cover each one tightly with a lid or plastic wrap.
- You could also use bell jars if you are so inclined, but these are not necessary.
2. Allow the yogurt bacteria to incubate. Keep the yogurt warm and still to encourage bacterial growth, while keeping the temperature as close to 100ºF (38ºC) as possible. The longer the mixture incubates, the thicker and more tangy the yogurt will be.
- 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.
3. Pick your method for incubating your yogurt. There are many methods available for incubating yogurt. Use a thermometer to make sure the temperature stays consistent. Choose the method that is most convenient and consistent for you. The most common way is to use a yogurt maker. The proper way to use a yogurt maker is detailed in the following steps.
- 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.
4. Choose a yogurt maker. There are several categories of retail yogurt makers available today, if you decide to use a yogurt maker (which is recommended.) Yogurt makers allow for the safest and timeliest incubation of the yogurt bacteria.
- 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.
5. Know the benefits of a yogurt maker. The user can adjust the temperature setting of the yogurt maker to maintain the proper temperatures associated with the bacterial strain(s) used in the culturing of the yogurt. Once set, they will maintain the setting, regardless of how warm or cold your home or kitchen may be.
- 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.
6. Place the containers of the cooled milk and starter in the yogurt maker. Make sure they are evenly spaced out and standing up straight (you wouldn’t want them to tip over or the yogurt could leak out.)
7. Supply a cover to keep in the heat. That maintains the containers at a temperature which, hopefully, allows the bacteria in the tempered dairy product in the containers go grow and thrive to make yogurt.
8. Check to see if the yogurt has firmed up. In due time – depending on bacterial strain(s) used, temperature and food available in the dairy product – the dairy product will firm up to a yogurt consistency. This can take as little as 2 hours and can last 12 hours or longer. The shorter times usually result in less tart yogurts and longer times provide completion of the bacterial growth. For those lactose intolerant folks, the longer times may produce a more digestible yogurt.
Remove the containers. Once the yogurt has gotten to the consistency and time desired, the containers are removed from the yogurt maker and placed in a refrigerator to cool for storage until consumption. The containers, which may be supplied with the yogurt maker, can be small cups so that the user can eat the yogurt right out of the cups. Containers as large as a gallon or more can be held by some yogurt makers for those who need large amounts of yogurt on a regular basis.
Make sure your yogurt is ready. Try gently jiggling one of the containers – the yogurt will not move if it is ready and you can take it from the yogurt maker and put it in the refrigerator then. Or you can wait and let it get more tart for 12 hours or more.
Adding the Finishing Touches
Strain the yogurt through cheesecloth for a thicker consistency. Put the cheesecloth in a colander and put the colander in a large bowl to catch the whey, which is a thin yellow liquid. Put the yogurt in the colander, cover the colander with a plate, and put it all in the refrigerator. Strain for a couple of hours for greek yogurt. Strain overnightfor a very thick yogurt, almost like soft cream cheese.
Refrigerate the yogurt. Place the yogurt in your fridge for several hours before serving. It will keep for 1 to 2 weeks. If you’re going to use some of it as starter, use it within 5 to 7 days, so that the bacteria still have growing power. Whey will form on the top. You can pour it off or stir it in before eating your yogurt.
- 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.
Add optional flavorings. Experiment until you develop a flavor that your taste buds fancy. Canned pie filling, jams, maple syrup, and ice-cream fudges are good flavorings. For a healthier option, use fresh fruit, with or without a small amount of sugar or honey.
Use the yogurt from this batch as the starter for the next batch.