How to make yoghurt at home

So what are the steps in making yoghurt?

Before you begin, thoroughly wash the equipment with hot, soapy water. Rinse everything thoroughly and air dry.

What you need

• Fresh whole milk from a cow, goat or camel is usually the best. In fact there is increasing popularity of making yoghurt from goat's milk. Any other type of milk for example from buffalo and sheep can be used. Whole milk makes thick and creamy yoghurt. Other than fresh whole milk direct from these farm animals, yoghurt can be made from low-fat or skim milk, including reconstituted dry milk powder. The amount of yoghurt required will dictate the quantity of milk used.
• Dried yoghurt culture or a cup of plain yoghurt.
• Insulated containers to incubate the culture or sufurias can be used. If just a small quantity is required then a wide-mouthed thermos can do.
• Sweeteners and flavors like sugar, honey or fruits
• A thermometer: though not very necessary but it makes things very precise. 

Procedure

Whole milk direct from an animal should be pasteurized before preparing yoghurt or any other milk product. Heat the milk to 72°C for at least three minutes or until it starts to froth. Stir the milk gently as it heats to make sure the bottom does not char and the milk does not boil over. Another way to prevent milk from burning is to create a double boiler by fitting two sufurias inside one another. Heating the milk changes the protein structure so that it sets as a solid instead of separating thereby improving the consistency of the resulting yoghurt.

Let the milk cool down to an optimal temperature around 45⁰C, or just when it is warm but not hot to the touch. You can achieve this by means of a cold water bath and gently stirring the milk.  If you intend to cool at room temperature, or in the refrigerator, then you must stir it more frequently.

Inoculate the milk as soon as the temperature falls to 45⁰C because this is the ideal growth conditions for the bacteria. You can do this by adding commercial yoghurt cultures, using plain yoghurt purchased from the supermarket or using yoghurt from the previous batch. Yoghurt starter cultures can be purchased at supermarkets but are quite expensive compared to plain yoghurt. But for best results purchase commercial cultured yoghurt to replenish a home made culture every four to five batches.

First warm the starter at around room temperature to prevent it from being too cold when you add to the milk. Add the yoghurt culture and gently stir to evenly distribute the culture throughout the milk. Or pour about a cup of the warm milk into a small bowl and whisk it with the yoghurt then whisk it back into the milk then stir to distribute the cultures evenly. Then cover the container.

The next step is incubation where the milk changes into yoghurt. Allowing the yoghurt to incubate encourages bacterial growth, breaking down the sugar in milk to produce lactic acid. The acid causes the milk to coagulate thereby forming thick yoghurt. Where an oven is used it should first be warmed to 35 – 40^oC. Wrap the milk container to insulate and keep it warm. Set the wrapped bundle in the warmed but turned off oven for 6-7 hours. The longer the yoghurt is left to incubate the thicker it becomes.

Alternatively you can incubate the cultured milk by placing it in a warm water bath and leaving it undisturbed for 6-7 hours at 35-40°C or until the yoghurt sets.  Change the water regularly after every hour because the water cools down with time. If you can afford, use commercial incubating equipment for maintaining a consistent temperature.

Test your yoghurt after 7 hours for taste and texture.  Note that the longer you incubate the yoghurt, the more it becomes thicker but this should not be done for more than 12 hours. A thick texture indicates that the yoghurt is ready for serving.

If you like you can add flavors and colors to your taste at this stage. For a healthy option, use fresh fruit, with or without a small amount of sugar or honey.

Refrigerate the yoghurt by placing it in a fridge for several hours before serving. Rapid cooling stops the development of other unwanted acid which makes yoghurt go bad. Cool the yoghurt preferably in the same container for a smoother end result. Then transfer it to clean air tight containers for easy storage. Yoghurt will keep for about 10 days if held at 4^o C or lower.

Starter yoghurt

To save you from buying starter culture or plain yoghurt as starter culture, keep some of the unflavored yoghurt but this must be used within 5 to 7 days.

Marketing

If the yoghurt was produced for sale, it should be hygienically packaged in suitable packaging material before taking it to the market. You can sell to restaurants or join together with other farmers to set up milk bars. There are many avenues to dispose of the excess milk if only you can look.