Made From Scratch: Yogurt in a Thermos!
Preparation: 15 minutes
Method: overnight, but with no attention at all
The quantity below makes enough to fill a 500ml/1 pint thermos
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1.5 cups/375ml/13floz of organic milk (best results with fresh)
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1/3 cup/40g/1.4ozs powdered milk
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1.5 tablespoons natural yogurt with live cultures (this is your starter)
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You will also need a thermos or glass jars with lids and several tea towels or bath hand towels if the weather is cold where you are. The recipe for blueberry sauce follows below.
Step 1 - Place the milk and powdered milk in a saucepan and use a small whisk to dissolve the powdered milk. Place a sugar thermometer in the saucepan and heat it to 82°C/180°F and then let it cool down to 46°C/115°F (it takes about 10 minutes, whisking and blowing on it helps and don't let it go below that temperature).
Step 2 - Meanwhile, preheat the thermos to give the milk a nice warm environment and to sterilise the thermos. To do this, put a kettleful of water onto boil and then pour the boiled water into the thermos and screw the lid on.
Step 3 - When the milk has reached the right temperature, whisk the yogurt into the milky mixture. Then empty out the water from the thermos (you can make a jug of iced tea with the water as it will still be very hot) and then add the milk and yogurt mixture to the thermos.
Step 4 - Screw on the lid tightly and then place in an area where it won't be knocked or disturbed. Wrap it in two or three tea towels or bath hand towels to keep it warm and leave overnight (although during summer the ambient temperature keeps it warm). Sometimes it may even be ready as quickly as in 7 hours but in cold weather it can take up to 16 hours to reach a good consistency. To store, place in the fridge and eat plain or with honey or with your favourite fruit topping.
Yogurt In The Oven
Step 5 - If you can't wait and want a quicker, cheesecake type of yogurt, make the milk and yogurt mix exactly as detailed above. Then instead of placing it in a thermos, preheat the oven to 150°C/300°F. While the oven is reaching temperature, preheat some 400ml (or thereabouts) glass jars with lids with the boiling water method above and then pour the water out and place the milk mixture inside and screw the lid on tightly. Turn the oven off and leave the jar/s in the warm but now turned off oven for 3-4 hours. The tart yogurt flavour won't have fully developed (and you can leave it longer to fully develop) so it will be very mild and creamy but it will have set quite nicely and you can top it with the blueberry sauce for a delicious, less calorific dessert (also add some vanilla and some crushed cookie crumbs if you want, for the cheesecake experience).
Blueberry sauce
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125g/4ozs blueberries (fresh or frozen)
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1/4 cup water
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1/4 cup sugar or to taste (depends on how sweet you want it and how tart the bluberries are)
Step 1 - Place ingredients in a small saucepan and simmer until the blueberries become soft and sweet, about 3-4 minutes. This will thicken naturally upon chilling. The fruit looks best on the bottom of the container underneath the yogurt as the whey rises to the top and tends to makes it look split.
Things to remember:
- Make sure all of your jars and thermos are very clean and sterilised (instructions below).
- Best results are obtained with fresh milk, not UHT
- You need to use fresh yogurt with live cultures-natural yogurt with live culture should be easy enough to find, just read the label, most contain them. Make sure that the yogurt hasn't expired as it may not work if the live cultures have died.
- You need it to reach 82°C/180°F to kill of any other bacteria that may compete with the bacteria we are using to create the yogurt.
- The longer the waiting process the more tart the yogurt will be. I found that the best results were after waiting 22-24 hours for the yogurt to set and that was lovely and tart and tasted exactly like the yogurt you get at the shops.
- If you get the clear yellow liquid, this is whey and is really good for your skin in a bath! It gives you very soft skin :) We should add that to things that clever girls can do.
- The yogurt should last about 1-2 weeks in the fridge.
- You can also use some yogurt from the batch that you made to make another batch of yogurt. However, use it within 5 days and be aware that there is a point where you can't use it anymore, after about 4-5 times as the live cultures will also expire.
- If you don't own a thermos you can put it in a sterilised jar or glass with a screw top lid-I baked a cake and while the oven was cooling, I placed the yogurt in a glass jars in the oven once it reached 150°C/300°F and let it set in the oven as it cooled down. It only took a few hours for it to set (but keep it in there longer if you want a tarter, more traditional yogurty flavour) and it was absolutely delicious. The tight lid is important and this really works best with jam jar sized quantities rather than large pyrex casserole dish quantities (also the lid doesn't screw on tight and that seems to really help speed up the process).
