Although it requires some effort, making yogurt at home yields a unique texture and taste, not to mention a minimal ingredient list. This recipe is a blend of many tips and strategies found online, tried and true now over a dozen times.
The idea is to have an aquarium heater indirectly keeping filled jars of milk and starter warm by maintaining water in the large vessel at a constant temperature.
Check the clock up front and make sure somebody will be at hand when the yogurt has finished incubating. For instance, starting at 10 a.m. will result in the incubation ending in the wee hours of the morning the following day.
All temperatures listed are precise and should be followed exactly.
- 1 large vessel for holding the heated water bath
- 1-5 glass jars for holding the yogurt during incubation and for storing it after
- 1 aquarium heater, 100-150W model capable of holding 77°F/25°C
- 1 food thermometer capable of measuring from 77°F/25°C to 185°F/85°C
- 1 cheesecloth or equivalent for protecting the vessel
- 1 double boiler or equivalent (constant stirring is an alternative)
- 1 empty sink for cold/icy water bath
- wooden stirring spoons
For holding the heated water bath, use a large 30-40 liter canning pot if you are making a lot of yogurt, or even a sink with the drain plugged. Keep in mind there needs to be enough space in it to hold all the jars as well as space for the aquarium heater to rest underwater without touching a jar. If making a smaller batch, consider other available vessels, but remember that the yogurt in the jars must remain under the water level and as above, there must be room for the heater.
When heating the milk, a double boiler is ideal but since a large enough double boiler will be hard to find, any pot is fine if constant stirring is applied to avoid burning.
The size of the jars is up to you but canning jars are great, around the 1L size. Having too much yogurt in any jar increases the risk of failure, but too many jars just makes life difficult (and lowers the possible water height, which might expose the heater element to air). Jars of a similar size are best because otherwise the water level might be simultaneously too high for some and too low for others.
The heater needs to be a high enough power that it can maintain the water at 77°F/25°C overnight. Depending on the length of the heater, it may be necessary to use a larger vessel so the heating element is completely submerged. An element exposed to the air is not safe and can overheat, resulting in situations you may not like.
Aquarium heaters often come with a temperature selection knob that only gives a rough estimate of the temperature. It is highly recommended to trial it before making yogurt and see at exactly what setting it keeps water at 77°F/25°C.
The use of wooden stirring spoons and only letting wood and glass contact the milk after mixing it with starter is superstition, but challenge it at your own risk.
- 1-4L milk, 1% or 2%
- 3 tbsp starter with active bacterial culture, per liter of milk
This recipe has been used with as little as 1 liter or as much as 4 liters of milk with no problems. Both 1% and 2% cow milk have been tried, and can be used interchangeably.
Preparation (15-60 min prior)
- Clean and prepare jars. There is no need to sterilize them.
- Let starter culture stand at room temperature.
- Prepare heated water bath in large vessel. Using hot and cold tap water, get the temperature as close to 77°F/25°C as possible, then plug in heater and place in vessel, ensuring coils are entirely underwater.
The cooling of the milk should be done as quickly as convenient, the faster the better to avoid the milk forming a skin. A cold water bath is fine, but even better is an ice water bath. If just cold water is used, it may be necessary to drain and replace it then continue the cooling.
Cooking (60 min)
- Heat milk gently to 185°F/85°C, stirring.
- Maintain milk temperature at 185°F/85°C for 15 minutes, stirring as convenient.
- While the milk is heating, prepare a cold/icy water bath for cooling the milk.
- Remove milk from heat. While stirring, cool milk in cold water bath to almost 77°F/25°C (stop a couple degrees early because the next step takes a couple minutes).
- Mix the starter with a part of the milk (maybe 2-3 cups) and stir gently. From now on do not bump anything containing this mixture.
- Pour non-mixed milk into jars, then gently add an amount of the starter/milk mix into each jar, proportional to the size of each jar. Stir each jar once with a wooden spoon.
- Ensure the heated water bath is at 77°F/25°C then place the jars into it. Do not close the jars. You may need to add a little more water to ensure the mixture and heater are covered.
- Lightly protect the vessel from dust and flies with cheesecloth or other thin cloth. If necessary, place something under the cloth to prevent it from touching the water or falling in.
- Make note of the incubation start time, and place a "do not bump/disturb" note in the area.
Harvest (14-18 hours after incubation start time)
- Remove the jars from the heated water bath. Check that they contain yogurt. If the milk is sour and still liquid, then no amount of further incubation will save it. Store and make use of the sour milk in other recipes.
- Set aside a small amount of yogurt to be the starter the next time. Mark it with today's date and use within a month.
- Close the jars. Chill them immediately in a refrigerator.
Optional: Fruit Bottom Cups (45 min)
This is an optional way to sweeten the yogurt and make ready-to-eat servings that can be taken anywhere.
Just like the fruit bottom yogurt cups found in the grocery store, the fruit can be pretty much anything. Some of the best choices include raspberries, blackberries, peaches, nectarines, strawberries, cherries, and apples. Even garlic when used in small quantities is a surprisingly great addition. Banana is not.
Individual plastic or glass containers can be obtained from a dollar store.
- Dice/mince/mash fruit (or garlic!) as desired.
- Stir over medium heat and add honey, stirring.
- Pour a couple tbsp into each container, then fill to brim with yogurt.