Yoghurt is a smooth semi-solid product made by the bacterial fermentation of milk. It is one of the most popular foods loved by many. It can be made with any type of milk by following the simple steps of:
- Pasteurizing the milk by heating,
- Adding yoghurt starter culture.
- Allowing the milk to incubate for 6 to 8 hours.
Yoghurt is a rich source of calcium and protein. Also, the fermentation process makes these nutrients easier to absorb. Apart from the obvious nutritional benefits of making your own yoghurt, you will have a product that is a fraction of the cost of what you will buy from the shops.
To make fantastic yoghurt all the time, you must always ensure that you pasteurize your milk by heating it. Also, make sure you clean and sanitize your containers and work spaces. You do all this to keep out unwanted spoilage bacteria.
It is also important you maintain a moderate incubation temperature. Streptococcus thermophilus and Lactobacillus
bulgaricus, the bacteria responsible for making yoghurt are thermophilic. Meaning that they like warm temperatures, but they can be killed at temperatures above 54°C and will not grow well below 36°C.
- 1 ltr Milk: I use whole fresh cow’s milk because that is what I get cheaply in my area. Better yet, you can use goat or camel milk if you have that.
- Starter culture: Streptococcus thermophilus and Lactobacillus bulgaricus are the cultures most often used to make yogurt. You can use dry cultures in sachets, but what I do is I buy a small cup of plain yoghurt with live cultures from the shops. Always check the label to see if it contains live cultures. For 1 ltr milk I use 2 tablespoons of fresh live culture. Keep it out of the fridge and at room temperature before using it as starter culture.
- A regular cooking pan large enough to hold all the liquid, plus have room to stir without the liquid going over the edge.
- Having a thermometer is good but do not worry if you don’t have it. I will show you how to estimate the optimum temperatures for making nice yoghurt.
- Containers for the yoghurt, for example glass jam jars.
- A spoon.
- For an incubator, I used a large hot pot because that is what I had in my kitchen. If you have an insulated cooler box, you can use that, and if you don’t have that either, use your blanket or duvet. Anything that will maintain a temperature of 42°C for 6-8 hours may be used as an incubator.
How To Make Yoghurt
Pour the milk in the cooking pan and slowly heat it to 85°C. Stir gently and constantly to maintain uniform heating and avoid scorching. Hold the temperature at 85°C to 93°C for 10 min for thinner yoghurt or up to 20 min for thicker yoghurt. Do not boil the milk. If you do not have a thermometer, heat the milk until you start seeing bubbles appearing like the milk is just about to boil. Reduce the heat and maintain that state for 10-20 min. Do not let it boil.
Cool and add starter
Remove cooking pan from heat source and place it in cool water to rapidly cool the milk to a temperature of 44°C – 46°C. If you do not have a thermometer, cool the milk while checking it’s temperature by carefully touching and sensing the temperature of the cooking pan. When it reaches the point where it doesn’t burn your skin on touching, i.e warm, you are ready for the next step of adding the starter culture. Remove one cup of the warm milk and mix it with the yogurt starter culture in a small bowl. Add this mixture to the rest of the warm milk.
Pour the milk and yogurt starter mixture into clean, sterilized warm glass jam jars. Cover and place in your incubator. Incubate the yogurt by setting it in a warm place for 6 to 8 hours undisturbed. The goal is to maintain constant temperature to allow the yogurt to ferment.
I maintain the incubation temperature by placing a plastic water bottle with hot water in the incubator. The ideal incubation temperature should be 40°C – 46°C.
Refrigerate yogurt immediately once it’s set to a jell-like consistency. Rapid chilling stops the development of acid. Yogurt will keep for up to 21 days if held in the refrigerator at 4°C or lower. Additions to the yogurt like fruit or sugar may reduce the shelf life. Discard any yogurt with visible signs of microbial growth or any odors other than the
acidic smell of fresh yogurt. Enjoy!