It was only recently that I decided to make my own homemade yoghurt. Even with so much tropical fruit on offer all year round, there was a little something missing from my breakfast table – a tub of thick, creamy yoghurt. And granola.
In Sri Lanka most local yoghurt is high in sugar, often not made with live cultures and instead set with gelatine. In a strange way, it’s like eating panna cotta for breakfast – a bit odd and not that good for you. Buffalo curd is widely available, but I’ve never really cared for the taste. Plus at 4-6% fat it’s not quite the healthy breakfast option. So I started doing some research into making yoghurt at home.
Did you know: ‘yoghurt’ is the Turkish word for milk that has been fermented into a tart, semisolid mass; it comes from a root meaning ‘thick’. – Harold McGee, On Food and Cooking
If you’re in a country with a decent dairy supply, you’re probably wondering why bother with making your own yoghurt? Have you ever looked at the list of ingredients on the back of a yoghurt tub? I was surprised to find that my favourite brand was 16% sugar. While I would happily eat a tub of Gippsland Dairy yoghurt as I would ice cream, I was under the illusion that yoghurt was the healthy option. A closer read of the label showed me that at 16.2g of sugar per 100g, it’s not far off the sugar content of a tub of Connoisseur ice cream (19.4g per 100g).
In a nutshell, it’s cheaper, it’s healthier and you’ll know exactly what goes into it if you make it yourself. There’s also the potential health benefits of live cultures – many people eat yoghurt for intestinal health.
Yoghurt remained an exotic curiosity in Europe until early 20th century, when the Nobel Prize winning immunologist Ilya Metchnikov connected the longevity of certain groups in Bulgaria, Russia, France and the United States with their consumption of fermented milks, which he theorized would acidify the digestive tract and prevent pathogenic bacteria from growing. – Harold McGee, On Food and Cooking
If you use a good starter culture, there’s a good chance that your yoghurt will probably taste better than store bought. I purchased mine from Bacillus Bulgaricus (affiliate link) because I liked the reviews. I have no regrets as it tastes great and my small starter pack has gone on to produce many more than the 30L it originally promised.
There are only really three steps to making yoghurt – heat, cool and culture. There’s no need for yoghurt makers, just attention to detail the first few times you make it. It becomes easier with practice and once you get into a routine.
For what is essentially a very simple process, it took me months to get the consistency of yoghurt that I wanted. Sometimes it was runny, other times lumpy and one time it didn’t set at all. Occasionally, I’d see a clear liquid (whey) leaking out around the sides. Although I initially blamed the milk, I’ve come to realise the little steps in the process that make a huge difference.
What types of milk can I use?
You can use pretty much any type of milk including skim, low fat, UHT or even non-dairy milks like coconut and soy (see below). Bear in mind that with only two ingredients, how good your yoghurt tastes will depend a lot on the quality of the milk you start with. UHT milk has a slightly oily aftertaste to me; I don’t drink it so I don’t use it in my yoghurt.
The higher the fat content, the creamier the yoghurt. As it turns out the yoghurt I was eating was not far off the fat content of ice cream! If you want to make a really creamy yoghurt, you can add cream to boost the fat content.
Reduced fat milk makes especially firm yoghurt because manufacturers mask their lack of fat by adding extra milk proteins. Whatever milk you are using, if you want firmer yoghurt, you can more milk solids in the form of milk powder. Either way, I suggest you try it with just milk to start in order to get a feel for how your yoghurt will set.
It’s a bit trickier to make yoghurt using non-dairy milks like coconut, almond, rice or soy milk as these commercially made products often have additives such as stabilisers and preservatives. I have never made yoghurt with these, but if you are planning to Ivo from Bacillus Bulgaricus* recommends adding a teaspoon of agar agar powder. Add it while heating the milk and only bring the milk to a gentle simmer to kill any competing bacteria.
Which yoghurt culture should I use?
I use Bacillus Bulgaricus* not just because I really like the taste, but because the customer service is really good. Ivo, the site’s owner is a wealth of knowledge on the subject and remains the main point of contact. He patiently answered all my questions, usually within a few hours, even at the odd times of day that I email him.
The company sources their bacteria from natural sources in ecologically preserved areas in Bulgaria. It produces a mildly tangy yoghurt with creamy consistency. There’s no good way to describe yoghurt, but I think of it as having very good, well-balanced yoghurt flavour. My friends will eat it on it’s own, but I often add a touch of honey. It is an heirloom strand so you can use your first batch of yoghurt to culture subsequent batches. Over a longer period of time, competing bacteria can affect the taste of the yoghurt (I’ve remade many batches from my first starter) so at that point, you’d start again with a quarter teaspoon of new culture. For that reason I’d recommend opting for a slightly larger pack than you think you need.
It’s also the only company I know that delivers worldwide. They have distributors in Australia, New Zealand, India, Canada, US, UK and Europe so your order is likely to get to you very quickly – often a couple of days.
If you are using a store bought yoghurt to start off your home yoghurt, use a good quality one and look on the label for live cultures or yoghurt cultures. Beware of anything that has gelatine or starch in it. Try to use a plain flavour as it will minimise the other bacteria or acids that might be in the fruit component of the yoghurt.
How do I get thick, creamy yoghurt?
As I mentioned above, milk with higher fat content produces creamier yoghurt and milk with higher protein content will set firmer. You can adjust the consistency of your yoghurt by adding cream (fat) or milk powder (protein) to your milk during the heating stage.
If you are looking to make a firm Greek style yoghurt you will need to strain off some of the whey. To do this, line a colander with a fine weave cheesecloth or muslin. Gather up the corners and tie it over a sink or weigh the yoghurt down with a saucer for a few hours. The liquid that strains off is called whey, and is often made into protein powders. It contains protein, probiotics and calcium – some manufacturers are touting is as a superfood, bottling and selling it. Use it in smoothies or baking or Google for more hipster ideas.
How long you heat the milk, and how you culture it also affects the final consistency. Read the heat, cool and culture steps below for more information.
Troubleshooting – feel free to post questions in the comments
Why is my yoghurt runny?
Assuming your milk is fresh, there are really only two main reasons that result in runny yoghurt (I’m referring to dairy milk bases here). Poor quality or dead starter bacteria, or improper temperatures for culturing.
Obviously if your starter culture is added to milk that is too hot, it will kill the bacteria and the milk will not culture. It’s also possible that your starter arrived dead to begin with, so use a reputable supplier. Don’t throw it out – you can reheat the milk and start the process again.
If the temperature is too cold, the bacteria takes longer to work it’s magic and culture the milk. It might be that you need to leave it for a few more hours or leave it in a warmer place.
Another possibility is that there wasn’t enough air for the bacteria. Make sure to cover with a vented or loose fitting lid, or simply cling wrap with holes poked in it.
Why is my yoghurt lumpy?
The most likely cause of lumpy yoghurt is bacteria that hasn’t fully dissolved. This is more likely to happen when starting a batch from powdered culture, but it’s an easy fix. After heating the milk, set aside a cup of milk in a medium dish. This smaller mass of milk will cool faster than what’s in the pot. When the cup of milk reaches about 38C (or when you can comfortably hold your pinky in the milk for 5 seconds), add the starter to it and mix thoroughly to ensure the starter is dissolved. Allow the culture to work in until the remainder of the milk (in the saucepan) reaches 38C, then combine the two and mix again.
Why does my yoghurt have a layer of clear liquid around the sides?
Most likely you’ve cultured at too high a temperature, or for too long. You can strain the yoghurt through a cheesecloth to make Greek style yoghurt, or simply mix with a whisk to homogenise the consistency.
Refer to the culture step below for more information.
The step by step:
Milk is heated to make yoghurt for three main reasons. Firstly, it kills competing bacteria that might be left over after the pasteurisation process (for instance bacteria from the carton, lid, etc). Secondly, it denatures the proteins in the milk, allowing it to gather in a fine matrix of chains which ensures a better consistency. And lastly, to create an ideal environment for the bacteria that coagulate yoghurt – they work best at a temperature of around 37-42C.
Harold McGee recommends heating at a temperature 85C/185F for 30 minutes of 90C/195F for 10 minutes. Unfortunately, heating for prolonged periods almost always results in a skin forming on top of the milk and some burnt proteins on the bottom of the pot. Use a non-stick pot, and a medium flame to heat the milk. Wetting the pan with water before adding milk will also reduce protein adhesion to the metal.
If you have access to good quality milk, it’s possible to make yoghurt by heating the milk to just 40-45C/104-113F to create an ideal environment for the starter. As protein and fat content can vary by seasons, this method produces less consistent results. It also results in yoghurt that’s a little thinner.
This isn’t really a step but I’ve included it because adding culture while the milk is too hot is often the easiest part to get wrong. It may be impatience, lack of a thermometer or that your yoghurt maker is running hot (a known problem with certain brands) but adding the culture to a mixture that is too hot is an easy mistake to make.
I always strain my yoghurt after mixing in the culture to remove any impurities like milk skin and coagulated bits of milk protein.
Once the milk has cooled to the proper temperature, the starter is added and the milk kept warm until it sets.
The fermentation temperature has a strong influence on yoghurt consistency. At the maximum temperature well tolerated by the bacteria, 40-45C/104-113F the bacteria grow and produce lactic acid rapidly and the milk proteins gel in just two to three hours; at 30C/86F, the bacteria work far more slowly, and the milk takes up to 18 hours to set. Rapid gelling produces a relatively coarse protein network whose few thick strands give it firmness but also readily leak whey; slow gelling produces a finer, more delicate, more intricately branched network whose strands are weaker but whose smaller pores are better at retaining the whey. -Harold McGee, On Food and Cooking
I don’t know about you, but 18 hours is way too long for me to wait for a yoghurt to set. I aim to add the culture at around 37C/98F, though sometimes I lose track of time. If so, I just gently reheat and add the culture.
Cover loosely with a lid, wrap it all up in a big beach towel or tea cosy and place in a warm-ish area. I use my oven, lightly preheated (then turned off!) for 1-2 minutes at 150C/300F to keep the warmth in for longer.
*This post contains affiliate links and I earn a small commission if you shop through them. This is a small part of how I continue to write and run this blog. I paid for the starter myself and recommend it because I love it.
- 2 litres milk
- ¼ tsp starter OR 1 cup of live culture yoghurt
- honey, to taste
- 1 tsp natural vanilla essence, or other flavour
- In a large nonstick pot, heat milk to 90C/194F for 10 minutes.
- Set aside roughly one cup of the milk.
- Allow the cup of milk to cool to around 37-43C (if you can hold your finger in it for five seconds, that is about the right temperature. If unsure, it's better for is to be cooler than too hot).
- Whisk in the starter or yoghurt into the cup and stir thoroughly to combine. (This ensures that the starter evenly disperses in the milk and starts working.)
- When the pot of milk reaches 37-43C, add the cup of milk to the pot and stir to combine.
- Strain to remove the milk skin and other impurities.
- If you prefer jars, place into clean jars and cover with loose fitting lid or glad wrap with holes poked into it - the bacteria need air to work their magic. You can culture your yoghurt in a large saucepan or bowl, then put into smaller containers when set.
- Whichever you choose, wrap in a towel and leave in a warm place for 6-12 hours.
- Check the consistency after six hours and leave to culture for longer if required. I like to lightly whisk some honey and vanilla into my saucepan of yoghurt, then store in 1 litre jars in the fridge.