Homemade Yoghurt

I started experimenting with homemade yoghurt because the brand of yoghurt I really like here in Australia (not too acidic, doesn’t have added fillers) is a pricey $7.50 a pot but it’s my favourite thing to eat for breakfast with fruit and my homemade granola. I was also hoping to make something my children would like because kids’ yoghurts have a lot of sugar and additives. If you’d like to have a go yourself, below are a few things I’ve learned from my trials and errors at home and my current simple method.

The basic principle of yoghurt-making is that milk needs to be mixed with a yoghurt ‘starter culture’ and kept warm for 8-12 hours until the bacteria has turned the milk to yoghurt.

If using fresh milk, the milk first needs to be heated to at least 90°C, which changes the protein structure and kills bacteria. The milk then needs to cool to 45°C before adding the starter culture (any hotter will kill the bacteria in the starter needed to make the yoghurt). I had problems at this stage with the milk scalding on the bottom of the pan and then a skin forming as the milk cools, making lumps! Both can be avoided with constant stirring if you are patient enough, or you can strain the milk into the container you will be making the yoghurt in once it is the correct temperature. My solution is to use UHT milk, which has already been heat-treated, so just needs to be warmed to 45°C to make yoghurt.

Homemade yoghurt tends to be runnier than shop-bought, especially if you’re used to greek-style. Using full fat milk and/or adding milk powder makes a thicker yoghurt. Also, the longer you leave yoghurt to set the thicker it will be (as long as it’s kept warm), but the acidity of it increases too. I recently forgot a batch and left it from 9am until 7am the next morning; it was really thick set, but very sour, so I didn’t really want to eat it! I’ve also not left it long enough before and it’s been quite runny and not ‘yoghurty’ enough – it tasted like milk that was a bit wrong! It’s up to you to judge where you prefer the thickness/sourness balance and that will tell you how long you need to leave your yoghurt to develop. I like it after about 10 hours.

Keeping your yoghurt-to-be warm for long enough can be a problem, and it’s very important; if it cools down too quickly the cultures will not do their job and the yoghurt either will not set at all or will stay pretty runny and tasteless. You can leave it longer and keep your fingers crossed, but anything over 12 hours will leave you with quite a sour flavour and it probably still won’t be as set as you’d like it. I’ve tried all sorts of things: I’ve sat my tub in an Esky cooler with warm water and I’ve wrapped it in blankets in a box with a heated wheat bag. An airing cupboard is a great place to leave it, but since I live in Australia and don’t have central heating, I no longer have one of those! My house changes in temperature quite a lot between seasons in my new home of Queensland, so, after some research, I decided to take the unpredictability out of my yoghurt-making. I bought an Easi-Yo yoghurt maker, which is pretty much a big thermos flask that you add boiling water to and sit your yoghurt-to-be inside. I can use the ingredients straight away from room temperature, and I’ve figured out how to make it without being dependent on the Easi-Yo sachets (see method below), so that keeps the cost down. It’s winter now and I’ve found that even with the Easi-Yo, it can cool down too quickly, so I’m using a small fleece blanket wrapped around it to insulate it.

Makes 1 litre/1kg

Ingredients

1 litre milk
1/2 cup milk powder (optional)
6 tbsp/1/3 cup live yoghurt or 3 heaped tbsp/1/3 of an Easi-Yo natural yoghurt powder sachet

Method

1. Heat the milk to 90°C (use an instant-read thermometer), stirring occasionally, then allow to cool to 45°C, stirring occasionally. You can speed this up by sitting the pan in iced water. Strain if needed. Alternatively, if using UHT milk, simply warm it to 45°C (use an instant-read thermometer).
2. Mix some of the warm milk with the live yoghurt or Easi-Yo powder and the milk powder (if using) in a bowl or jug, before whisking into the rest of the warm milk.
3. Put a lid on the pan or pour into a lidded container and insulate using your method of choice (a towel or blanket wrapped around it plus airing cupboard, radiator, oven with just the light on, or a warm Esky). Check after 8 hours, leave for up to 12 hours.
4. Chill (it will set a bit more in the fridge). Your yoghurt will keep for a week or more.

or – if using an Easi-Yo yoghurt maker:

1. Pour 500ml room temperature UHT milk into your Easi-Yo yoghurt jar.
2. Add the live yoghurt or Easi-Yo powder and milk powder (if using) to the jar, put the lid on and give it a good shake, add more room temperature UHT milk up to the fill line, put the lid back on and shake again.
3. Pour boiling water into your Easi-Yo yoghurt maker up to the top of the plastic insert spacer, sit the jar in the water and put the lid on. Wrap in a blanket or towel. Check after 8 hours, leave for up to 12 hours.
4. Chill (it will set a bit more in the fridge). Your yoghurt will keep for a week or more.

Tips

You can save some of the yoghurt you’ve made to make your next batch, but the cultures only last so long, so this may only work for 1 or 2 batches before it starts to taste funny or not set properly. You should then go back to a shop-bought yoghurt or some of an Easi-Yo sachet as a starter culture.

To make vanilla yoghurt, add 1-2 tbsp sugar and 2 tsp vanilla extract to the milk in step 1 above. You can also stir jam or honey into the yoghurt to flavour it once it’s made.

Leave a comment if you give this a go and let me know how you got on!