Hi everyone! Today, I’m going to share with you my yogurt recipe, and I’m also here to debunk some myths about making yogurt yourself.
First of all, there are a few things you need to understand, namely a) the “science” behind yogurt making, b) the raw materials needed and c) factors that affect your success.
Let’s get straight into it.
a) The “science” behind yogurt making
Well, it is essentially, bacterial fermentation, so what you need here are bacteria (“Starter Culture“), and food (“Medium“) for the bacteria (they eat carbs like we do!), so they will act on the food and convert it to lactic acid.
Note: Lactic acid is a by-product of carbohydrates during the process of fermentation, it is not unique to lactose.
b) The raw materials needed
As highlighted above, you need Starter Culture. I think the main distinction we need to make here is that, there are two types of starter culture – thermophilic and mesophilic. The main difference? Thermophilic bacteria prefers a higher temperature (40°C – 70°C) and mesophilic bacteria prefers room temperature. One thing to note is that thermophilic bacteria will die at a temperature exceeding 70°C (better be safe than sorry, so let’s set a hard cap at 70°C).
If you use the thermophilic strains, you will need a constant heat source – in this case I use a thermos. If you have more budget, you can use sous vide *cough, or a yogurt maker. Otherwise, oven will work too. I like a thermos because it is low cost and easy 🙂
You can obtain the Starter Culture from store-bought yogurt (make sure the ingredient list says “Active Culture“!), or stuffs like probiotic capsules.
The second is the Medium. It can be dairy / non-dairy. It doesn’t matter as long as it has carbohydrates (or sugar). The fermentation process will proceed to convert the carbs to lactic acid. Once the pH drops below 5 due to the metabolic process of the bacteria, the milk begins to curdle as the protein changes its structure – and here, you get the yogurt texture you love.
c) Factors that affect your success
Factors that affect your success in yogurt making? I will say it is the temperature, especially when you’re using a thermophilic strain (which is also more common, to be honest).
Secondly, it is the composition of the milk you use. Dairy is kinda fool proof because the composition is more or less similar. For non-dairy, if it has little protein, you have to add thickener. If it’s already creamy due to its fat composition, you can save the thickener. If it doesn’t have carbs, add some sugar, whether it is in the form of syrup, or coconut water.
Thirdly, some says it depends a lot on the starter culture you use. Personally I haven’t been experimenting on this a lot, but I believe the first two factors are more critical as they are the fundamentals of the fermentation process.
It is time for the steps! The amount required is kinda an art in my case, but hey, as long as you get the basics right (as stated above), everything is gonna fly! (Hopefully)
I’ve experimented it myself – I tried making yogurt using F&N coconut ice cream. I didn’t like the ice cream because it was too sweet for my liking. As I looked through the composition of the ice cream, I got an “A-Ha” moment, and decided to use it to make yogurt instead. After all, if the bacteria eats sugar, the product will become less sweet – and it turns out, I’m right!
- Heat the ice cream up to 50°C and cool it to about 42°C. You can heat it to a higher temperature for a longer period of time if you want to kill any potential pathogens. You just need to cool it longer. Don’t forget to use a thermometer. (duh)
- Meanwhile, warm the thermos with hot water.
- When the melted ice cream falls to about 42°C, add the starter culture. (I used store-bought yogurt)
- Stir well.
- Pour the water out of the thermos and use it to make tea.
- Add the mixture (starter culture + medium) to the thermos.
- Set aside for 8 – 12 hours. You can leave it longer if you want.
The yogurt does taste better – now I know what to do with the 1.5 litre tub of ice cream!