We have plain yogurt with breakfast every day and both prefer a fairly thick style. I read that making yogurt at home is quite easy and own a KitchenAid heated bowl suitable for its incubation. One of the main reasons for attempting to make it is to reduce the number of plastic pots: two 650g pots per week seems like a lot of plastic which we might be able to avoid.
2 litres 3.25% Lactose free milk
½ cup Olympic Organic Balkan-style 3.5% MF plain yogurt (or Astro lactose free Balkan style)
This yields about two 650g pots. I read that converting milk to yogurt separates most of the lactose into the whey which can be mostly strained out so ordinary milk would probably be OK if the whey is discarded but I use some of it for baking and stir some back in if the yogurt is very thick.
Saucepan to scald milk, cooking thermometer accurate around 100C (200F) with probe which can be used to stir liquid, heated bowl
Heat milk in pan to 85C to 90C (185F), stirring while heating to prevent it burning. Leave at around that temperature for several minutes; this alters the protein structure so the yogurt will set. Cool milk to around 45C and set heated bowl to 110F. Pour most of the milk into the heated bowl. Stir the remainder of the milk with the half cup of yogurt and add to milk in the heated bowl, stirring gently to distribute it through the liquid. Leave to incubate for around 8 hours at 110F. The longer it incubates the thicker and more acidic it becomes.
After incubation it is set and could be used after chilling but we prefer it strained. I use an old worn, and therefore thin, linen teatowel but two thicknesses of cheesecloth is also recommended. I line a steel colander with the teatowel and place it over a large bowl before transferring the set yogurt to the lined colander. I leave it to strain for at least an hour before transferring the yogurt to storage pots in the fridge. I retain 2 cups of the whey (the yellowish liquid left in the bowl after straining) to use for baking muffins. It can be used in place of milk in baking recipes as it contains protein.