If you can heat milk, you can make yogurt. Stir in starter and keep it warm, and in a few hours you’ll have pure, additive-free, probiotic-packed yogurt. It’s wonderful for baking (an excellent buttermilk substitute), cooking, smoothies or eaten simply with berries and a drizzle of honey.
Ingredients (scale up as you like)
- 1 quart (4 cups) milk, whole or lowfat
- Yogurt starter (1 tablespoon plain yogurt with active bacteria or powdered yogurt starter)
- Heat milk in a saucepan over medium heat. Heat until near boiling (milk will be very steamy, with some bubbling at edges), but don’t let it boil. Turn off heat and cool milk to about 115 degrees F, until your freshly-washed tester finger can stay in comfortably for 10 seconds. You can put the pot in a cold-water bath to speed the cooling process, but take the pot out early enough that you don’t risk overcooling the milk. Yogurt bacteria die at temperatures above 130 degrees F, and they don’t grow well below 98 degrees F. But a 30-degree window is a lot of leeway, so don’t stress – if it feels comfortably warm to your touch, you’re in the right range.
- Have a clean, dry jar and lid ready. I love a quart-sized mason jar, but you could also make your yogurt in the pot or divide it into smaller jars.
- Take your yogurt starter (powder in a packet or a spoonful of plain active yogurt) and mix gently with a ladleful of warm milk. Pour the mixture back into the pot (without stirring) and divide into jars, if using.
- Yogurt needs to be kept warm as it ferments – 100 to 110 degrees is ideal. You can keep it in an oven – an incandescent oven light bulb turned on, or a pilot light, should keep it warm enough (just don’t accidentally preheat your oven for cooking while the yogurt ferments). Another good method is to put jars of yogurt in an insulated cooler (add a jar of hot water from the tap if you need to give a little extra warmth to a large cooler). Some people even wrap jars of yogurt in blankets or towels for insulation.
- Yogurt can ferment for as little 3-4 hours or as long as 24 hours. The yogurt bacteria consume lactose as they multiply, and after 24 hours the yogurt has close to minimum lactose and maximum probiotic content. But a shorter fermentation will . If it still seems runny when you check on it, add a little more heat (just a few seconds of turning the oven on, or adding/replenishing a hot water bottle in the cooler) and go away for another few hours.
- Remember that your yogurt will only be as good as your starter, so make sure you use a high quality plain yogurt (eg Fage) or starter (eg Yogourmet).
- Cooling time for the milk depends on the size of your pot and the volume of milk. A quart might take 20 minutes; two quarts can take 45.
- A skin will form at the surface of your milk as it cools. I skim it off to allow steam to escape and discard it, but it doesn’t hurt to stir it in – it will just end up in the top of your finished yogurt.
- Some people add nonfat dry milk powder for extra thickness, particularly if they are using very low-fat milk. I prefer whole milk with no powder.
- Yogurt doesn’t like to be jiggled, so for a nice, creamy consistency, keep it still as it ferments.
- Save some untouched yogurt (you may want to spoon some out into a small jar) for starting your next batch. Though after several grandfathered batches, I generally restart with a fresh starter for better oomph.
- Don’t stir the finished yogurt unless you like a runnier texture.
- The bit of watery liquid on the top of the yogurt is just whey; eat it or pour it off as you like.
- For thicker Greek-style yogurt, you can strain your yogurt in a fine-mesh or chessecloth-lined strainer for several hours. The whey that drains out may be used as a nutritious liquid in breadmaking, smoothies, etc.
- A longer-fermented yogurt, with its low lactose content, is more digestible and packs a bigger probiotic punch.
- Yogurt keeps well for at least a couple weeks in the fridge. It will easily last past that, but its probiotic content may begin to decline.
- Yogurt can be frozen for longer storage, though the texture will be affected somewhat. You can also freeze small amounts of yogurt to keep as future starters.
Here’s a link back to the post and pictures.