Sugar – Home-make yogurt: add sugar / something else with the starter

I was sure that with all the questions and answers we have had about yogurt that this simple question must surely have already been asked. But I couldn't find it.

Making yogurt is simplicity itself.

The goal is to introduce heat-loving (thermophillic) bacteria to milk, keep them warm so that they munch on the lactose in the milk turning it into lactic acid. The acidity and warmth denatures the milk proteins and turns the whole mass into a gel.

The steps may vary a little depending on your equipment and the bacteria that you use.

1. Get milk. -- The more fat the better it will taste. Powdered milk can also be added to improve the texture as it will add more protein.
   
   
2. Get a starter. -- Any commercial yogurt that advertises "live active cultures" will work just fine. Pick a yogurt that you like as the yogurt you make with those cultures will be similar.
   
   
3. Heat the milk to about 85°C (190°F) for a few minutes. -- This will denature the albumin in the milk which will add to the yogurt structure instead of leaking out with the whey.
   
   
4. Cool the milk at to between 40°C (110-120°F). -- 55°C (130°F) will kill your starter.
   
   
5. Mix in the starter.
   
   
6. Keep the mix warm for 6-10 hours. -- The longer the more acidic and firm it will get. The exact temperature will depend on your starter and equipment. Danon plain yogurt, as a starter, wants to stay at 37°C (100-110°F). My Indian coworker's starter that she brought from India can thrive at almost room temperatures.
   
   "Yogurt makers" can be purchased that simply hold their contents at about 100F. Some people use heating pads. Some people set their oven on low. You can be creative- just don't get hotter than 55°C (130°F) or cooler than 30°C (90°F) or so.
   
   To try it out for the first time I would recommend simply putting your yogurt in a heavy, lidded, container, wrapping in a towel and letting it sit in the turned-off oven for 5-6 hours.
   
   
7. For a thicker creamier texture you can strain your yogurt. -- After it has fermented to your liking stir it up well, pour it into a piece of muslin in a strainer, and let it drain for a little while. The whey draining off is good for baking. It has some calcium, b12, and a lot of lactose. (If you skipped step 3 it also has a lot of wasted protein).

Making your own yogurt is a fun activity. You get to pick what goes into it so there is no sneaky ingredients and you can make it for a fraction of the cost of commercial. Play around with different starters. Different bacteria will produce yogurt with different qualities and it is interesting to experiment.

To sweeten it, add your favorite sweetener: sugar, honey, agave... whatever you prefer. This is important, because sweetness will help bring out the flavor of the fruit.

General advice:

If you have a fruit you want in your yogurt, pick the form (chunks, pureed, mashed, juice) that you want and mix it in. The Chobani yogurts appear have a variety of these forms, always along with some sugar. If you want banana flavor, sure, mash up a banana and mix it in. Or if you want chunks of fruit, chop it up. Assuming the fruit is soft enough, for this purpose, mashing with a fork is probably a good substitute for pureeing; you'll get some small chunks and some juice.

In response to the updates:

if you want actually fruit-flavored yogurt, then you need juice and/or puree. If you don't have any other tools, mash it as best as you can. If you have a small food processor or blender that will work with small enough quantities (or are making big batches), blend things up and stir them in. Juice and puree will disperse quite well through the yogurt.

Bananas mash easily, especially ripe ones, so just do that with a fork. Strawberries aren't as soft, but you should get enough juice to flavor with if you mash them. Pineapple is tougher. If it's juicy enough, you can probably get some juice out by mashing it; otherwise you might be better off with a food processor or blender. (If it's from a can, you can use the liquid from the can, too - that might also have sugar in it.) Depending on how thorough you are, you may want to use the juice and discard the fibrous parts that are left over.