If you’re wondering how to make yogurt at home, here’s the short version: heat milk to around 85°C, let it cool to about 43°C, stir in a spoonful of live natural yogurt as your starter culture, then keep it warm for 6 to 12 hours until it sets. You don’t need a yogurt maker, though one makes the temperature easier to hold steady, and the whole process uses ingredients most UK kitchens already have.
This guide walks through the full method step by step, covers the main ways to keep your yogurt warm while it ferments, deals with the food safety questions people often skip over, and answers the most common troubleshooting problems.
What You Need to Make Yogurt at Home
You only need two ingredients: milk and a starter culture. For the milk, whole pasteurised milk gives the creamiest, thickest result, though semi-skimmed works fine if you want something lighter. Most milk sold in UK supermarkets is standard pasteurised milk, heated to around 72°C for 15 seconds during processing, which is exactly the kind you want for this.
For your starter, a couple of tablespoons of shop-bought natural yogurt containing live active cultures does the job perfectly well, and once you’ve made your first batch, you can use a spoonful of that to start the next one instead of buying more. Check the yogurt pot’s label for “live cultures” or “active cultures”, since some supermarket yogurts have been heat-treated after fermentation and won’t work as a starter.
You’ll also want a cooking thermometer, since guessing the temperature is the single biggest cause of yogurt that never sets properly, plus a large saucepan, a whisk, and whatever container you plan to incubate and store the yogurt in.
How to Make Yogurt at Home: Step by Step
Step 1: Heat the milk
Pour your milk into a large saucepan and heat it gently over a medium heat, stirring occasionally to stop a skin forming on top or the milk catching on the bottom. Bring it up to around 85°C, which usually takes 15 to 20 minutes depending on your hob and how much milk you’re using.
Heating the milk this high, rather than just warming it, helps denature the proteins and gives you a thicker finished yogurt, so don’t skip this step even though it takes a bit of patience.
Step 2: Cool the milk to the right temperature
Take the pan off the heat and let the milk cool down to around 43°C, which normally takes 30 to 45 minutes at room temperature, or you can speed it up by standing the pan in a sink of cold water. This step matters because adding your starter culture while the milk is too hot will kill off the very bacteria you need to make yogurt.
Step 3: Add your starter culture
Take a small ladleful of the cooled milk and whisk it together with your two tablespoons of live natural yogurt in a separate bowl or jug, which helps the culture mix in evenly rather than clumping. Pour this mixture back into the rest of the milk and stir gently but thoroughly.
Step 4: Keep it warm to ferment
Pour the mixture into your incubating container, cover it, and keep it somewhere warm and undisturbed for 6 to 12 hours. The exact time depends on how tangy and thick you like your yogurt, so it’s worth checking after 6 hours the first time you try this and noting what works for your setup.
Step 5: Chill and store
Once the yogurt has set to a consistency you’re happy with, move it to the fridge, where it will thicken further as it cools. Homemade yogurt keeps for around two weeks in the fridge in an airtight container, similar to shop-bought natural yogurt.
Ways to Keep Yogurt Warm While It Ferments
Using a yogurt maker
A dedicated yogurt maker holds a steady temperature automatically, which takes the guesswork out of incubating and is the most reliable option if you plan to make yogurt regularly. Basic electric yogurt makers are widely available in the UK from around £20 to £40, and most come with a set of small individual pots as well as the main unit.
Using your oven
If your oven has a very low setting or just the pilot light and oven door light, you can pour the yogurt mixture into a covered dish, place it inside, and leave the door slightly ajar to stop it overheating. This works well as long as you can keep the temperature fairly steady around body heat rather than properly warm.
Using a flask or slow cooker
A wide-necked vacuum flask holds heat well and needs no power, making it a good option if you don’t want to leave an appliance running for hours. A slow cooker on its lowest setting, or simply switched off after briefly warming through, can also work, though it’s less reliable for holding a precise temperature than a dedicated yogurt maker or flask.
Food Safety Notes for UK Home Cooks
Standard pasteurised milk from a UK supermarket is safe to use for homemade yogurt and is what most recipes assume you’re working with. If you’re considering using raw, unpasteurised milk instead, be aware that the Food Standards Agency advises that raw milk can contain harmful bacteria and specifically recommends that pregnant women, young children, elderly people and anyone with a weakened immune system avoid it altogether.
Keep your equipment clean by washing pans, jars and utensils in hot soapy water before you start, since a clean environment helps the right bacteria dominate the ferment rather than competing with anything unwanted. If your finished yogurt smells off, shows mould, or separates into odd colours rather than a thin layer of whey on top, it’s safer to discard it and start again rather than risk it.
Common Mistakes to Avoid
Adding the starter culture while the milk is too hot. This kills the live bacteria you need, so always let the milk cool to around 43°C, checked with a thermometer, before stirring the starter in.
Using a starter without live cultures. Some yogurts have been treated after fermentation and no longer contain active bacteria, so check the label specifically says “live” or “active cultures” before using it to start a batch.
Disturbing the yogurt while it’s setting. Moving, stirring or jostling the container during incubation can stop it setting properly, so find it a quiet spot and leave it alone until the time is up.
Incubating for too short a time on your first attempt. New yogurt makers often give up too early, checking at 4 hours and assuming it’s failed, when many batches need the full 6 to 12 hours to set properly depending on temperature and culture strength.
FAQs
How long does homemade yogurt take to set?
Most homemade yogurt takes between 6 and 12 hours to set, depending on the temperature it’s kept at and how tangy you want the final result. Longer incubation generally means a thicker, more sour yogurt, so it’s worth experimenting to find your preferred timing.
Do I need a yogurt maker to make yogurt at home?
No, a yogurt maker isn’t essential, though it does make holding a steady temperature much easier than alternatives like an oven, flask or slow cooker. Plenty of people make good homemade yogurt with nothing more than a saucepan, a thermometer and a warm spot in the kitchen.
Can I use UHT milk to make yogurt?
Yes, UHT milk can work for homemade yogurt and some people find it gives a slightly thicker result since it’s already been heated to a high temperature during processing. You can generally skip the initial heating step with UHT milk, though many recipes still recommend a brief warm-up to be safe.
Why didn’t my homemade yogurt set?
The most common causes are adding the starter culture while the milk was too hot, using a starter without live active cultures, or not keeping the mixture warm enough or for long enough during incubation. Check each step with a thermometer next time rather than guessing by feel.
Is homemade yogurt safe to eat?
Yes, homemade yogurt made with pasteurised milk, live cultures and clean equipment is safe for most people to eat. If you’re using raw, unpasteurised milk, the Food Standards Agency advises pregnant women, young children, elderly people and those with weakened immune systems to avoid it.
How long does homemade yogurt last in the fridge?
Homemade yogurt typically keeps for around two weeks in the fridge when stored in a clean, airtight container. If it develops an off smell, visible mould, or unusual colouring beyond a thin layer of whey on top, it’s best to throw it away rather than eat it.
Can I make Greek-style yogurt at home?
Yes, simply strain your finished homemade yogurt through a muslin cloth or fine sieve set over a bowl for a few hours in the fridge, which drains off the whey and leaves a thicker, more concentrated Greek-style yogurt. The drained whey can be kept and used in baking or smoothies rather than thrown away.
Can I use plant-based milk to make yogurt?
Plant-based milks like soya or oat milk can be used, but they generally need a thickener such as agar agar or cornflour added, since they lack the milk proteins that naturally thicken dairy yogurt. Results are more variable than with dairy milk, so expect some trial and error if you’re making a plant-based version for the first time.
