Greek Yoghurt
This recipe is the result of trials of several different milks, including whole milk, lactose free milks, and high protein milk. In the end, whole milk gave the most traditional flavour.
Traditionally, Greek yoghurt is made by straining plain yoghurt to remove whey. This concentrates the proteins and fat, giving it its characteristic texture. In comparison, Greek-style yoghurt is not necessarily strained, but it is thicker than ordinary yoghurt, and may even be set in the final jar or pot.
Straining the chilled yoghurt resulted in my favourite of the trials. You can even strain it all the way to being a labneh if you like. Note that straining makes the use of skim milk powder completely unnecessary.
Try your hand at making it without the skim milk powder then read the notes to understand how to best adjust to your taste for tanginess, thickness and creaminess. There is definitely some trial and error required to adjust for your personal process, equipment, and taste – for example a lower incubation temperature will result in less tang in the same 8 hour period.
Greek Yoghurt
Traditional thick and creamy Greek yoghurt
Equipment
- Digital Thermometer - Use a thermometer with a separate probe and reading unit, ideally with a probe that can be attached to the pot. This will allow keep your hands free during cooking and the probe can later be used to record air temperature in the incubator without opening it.
- Incubator - You can make your own using hot water bottles and towels in an esky or a foam box. Alternatively, use the oven with only the light on (no heating).
- Glass Jars - Use jars with a wide mouth. Plastic can be ok but it needs to be both food safe and safe to wash in a dishwasher.
Ingredients
- 1 litre milk (whole milk)
- 20 grams skim milk powder (optional)
- 20 grams yoghurt (starter)
Instructions
Prepare Equipment
- Before you start, sterilise the jar(s) and equipment that will be used to prepare the yoghurt.
- If using an esky or foam box incubator, ensure your jars fit, allowing room for hot water bottles and towels. Do not fill the water bottles yet.
- Attach your thermomenter to the side of a heavy based saucepan or pot with a smooth surface. Milk is less likely to catch on the bottom of a smooth pot during heating.
A thermometer with a separate probe and reading unit makes life much easier!
Prepare Yoghurt
- Combine the cold milk and the skim milk powder (if using).1 litre milk, 20 grams skim milk powder
- Heat the milk to 88°C, stirring very regularly.
- Carefully hold the hot milk at 88°C for 20 minutes, still stirring regularly. Do not boil. Keep the temperature between 85°C and 90°C.
- Cool the milk to 43°C stirring occasionally. To speed this up, place the pot (with the milk in it) into a shallow depth of cold water in the sink.
- As the milk cools, prepare the incubator – fill hot water bottles with the hottest tap water you have – not boiling water. If your hot water is temperature regulated, you may need to add a bit of boiling water. If using your oven, turn the light on and ensure heating is off. Line the walls of the incubator with the hot water bottles. Place a towel at the bottom of the incubator and have another ready to go on top.
- Pour all of the prepared milk, through a fine mesh sieve, into a jug (or strain it straight into the jar if using a single jar). This will remove any milk that caught at the bottom of the pot and any milk skin that formed.
- In a separate small bowl, mix the yoghurt starter with about ½ cup of the strained milk until smooth. Don’t skip this – it is important to ensure that the yoghurt is evenly combined.20 grams yoghurt
- Pour the starter mixture into the main jug (or jar) of milk and stir gently, avoiding air bubbles forming, until evenly combined.
- Pour the yoghurt into the jars for incubation and loosely close the lids.
Incubate
- Arrange the jars in your incubator and place the probe of the thermometer in the incubator so that it only reads the air temperature – it should not have contact with the hot water bottles, oven shelves, oven elements or the jars.
- Incubate for 8 hours at 40-42°C.
Chill and Strain
- Without disturbing the yoghurt, close the jar lids fully, and place the jars straight into the refrigerator. Leave them undisturbed for 12 hours.
- For a true Greek yoghurt, strain the cold yoghurt for a few hours in a cheesecloth lined strainer, sitting clear on top of a bowl in the fridge, to allow the whey to pass through. Strain time is to your taste – around 6 hours will give you quite a thick yoghurt.
Notes
Yoghurt has several aspects and it is important to how to control each one so you can adjust to your personal preference.
Tanginess
Tanginess is mainly controlled by incubation time. The longer the yoghurt incubates, the more lactose is converted into lactic acid, producing a tangier flavour. Higher incubation temperatures also increase acid production, while refrigeration slows it dramatically.
Thickness
Thickness is influenced by several factors:
- Heating and holding the milk to 88°C for 20 minutes strengthens the protein network.
- Higher protein content (for example, by adding skim milk powder) produces a thicker yoghurt.
- Straining removes whey, creating a much thicker Greek yoghurt.
- Whole milk generally produces a firmer set than reduced-fat milk.
- Holding the milk at 88°C for 20 minutes, allowing the whey proteins to strengthen the gel.
- Avoiding movement or vibration while the yoghurt is incubating and until it has chilled.
- Cooling the yoghurt promptly after incubation to stop further acid production.
- Avoiding excessive incubation, as over-acidification causes the protein network to contract and squeeze out whey.
- Keeping the finished yoghurt refrigerated and handling it gently, as stirring and repeated scooping can release additional whey.
