Why make your own yogurt?
- You can avoid all those plastic containers (especially if you buy the milk in returnable bottles).
- It’s healthy. Studies show that the lactic acid bacteria plentiful in homemade yogurts are good for you.
- It’s cheaper than buying it.
- It tastes fresher and tarter.
Choosing your starter
To ferment your own yogurt, you can simply use a bit of store-bought yogurt- make sure it’s the type with “active cultures”- as a starter.
For a bit more consistent results you can use freeze-dried bacteria. You can find these in specialty stores or simply by searching online under “yogurt starters” (We have a video on making your own yogurt from a package consisting of powdered milk and cultures).
There’s also the option that you have a friend or acquaintance who makes their own yogurt and offers you an heirloom starter, something that has been passed down often through generations.
Choosing your milk
You can make yogurt with any type of milk from non-fat to soy. Experiment with what works best for you. Nonfat can produce a harsher taste. Soy can be thinner. Whole milk is a bit more consistent.
- 2 tablespoons of regular yogurt or starter (or the required amount of freeze-dried bacteria)
- 1 quart of milk
- * 1/4- 1/2 cup nonfat dry milk (optional): can help thicken the yogurt especially if you’re using nonfat milk.
While an oven with a pilot light and a candy thermometer make it easier to determine more exact temperatures, you can do without either.
Really all you need are these basics:
- A pan or double boiler (or make your own double boiler with 2 pots that fit within each other).
- Containers with lids: recycled yogurt containers, tupperware.
- Heat milk to 180- 190°F (85-88°C), or if you’re not using a thermometer, heat it to the point where the milk starts to froth: when it’s steaming and beginning to form bubbles. You can heat the milk directly with just one pan, but if you have a double boiler or two pots that fit inside each other, it will prevent your milk from burning. If you are using just one pan, make sure to stir constantly.
- Let milk cool to 110-120°F (43-49°C). If you’re going by touch, it will feel very warm or even hot. The quickest and least labor intensive way to cool the milk is by putting the pan in a bath of cold water. If you let it cool at room temperature or in the refrigerator, make sure to stir often. Don’t let the temperature drop below 90°F (32°C).
- While waiting for the milk to cool, let the starter sit at room temperature.
- If you’re adding nonfat dry milk, do this now. Add 1/4 to 1/2 cup powdered milk.
- Add the starter. Either stir in the freeze-dried bacteria or add 2 tablespoons of store-bought yogurt (or from your last batch). Rather than adding the yogurt directly, it’s helpful to thin the yogurt first by mixing it with a little of the milk.
- Pour the mix in a container or several small containers, closing them with a lid or covering them.
- Keep the yogurt warm and still- so the bacteria can grow- until it has set. This should take about 4-7 hours. The longer it sits the thicker and tangier it will be. To keep yogurt warm, you can simply wrap your containers in kitchen towels, or you can put it in the oven with the oven light on. Other places to keep it warm: a sunny window, hot water in the sink, a crock-pot, a large thermos, a heating pad, etc.
- Once the yogurt has set, put it in the refrigerator to firm it up and slowdown acid production. It will keep for 1-2 weeks. If you want to use some of the batch as a starter for a new batch, be sure to use it within a week for the bacteria to be effective.
- *Optional: add flavorings. You can use anything from jams to chocolate sauce.
- NY Times article on fermenting your own yogurt.
- Wikihow on making yogurt.
- Our video on making yogurt from a package of dried cows milk and cultures.