I like the tried and true method with brewers yeast and potato flakes etc., there are some great recipes on DF. Some people do use fruit but for me and how many cultures I make would not be cost effecient plus sounds like a pain.

Here is the Media link: FF media preference

How much sugar and yeast do you add?

I'd like to know this too please.

So if I understand correctly, just one culture, after it reproduces for the first time, will give you the basis needed to make the second culture? Then that second culture, after it reproduces for the first time, will then give you what is needed to make the third culture and so on and so forth?

-Kelly

You got it Kelly. You'll be able to start multiple cultures from one culture. Each culture typically only needs 30 -50 flies or so to seed it. With a good mix in there for the flies to feed on, one culture will produce a lot of flies. Starting more than one culture at a time to isn't a bad idea. It's always better to have to many flies than not enough. Not to mention that if one culture fails, you'll have others (because oh yes, that'll happen )

Thought I'd actually post the recipe I use here. I will admit that I decided on one that involves a little more work to make, but my results are fantastic! Since I started making my cultures this way it's eliminated all mold and smell issues.
To agree with Beth though, if your doing it on a larger scale this might not be the most cost effective way to produce your cultures. Not to mention it's clearly more time consuming.

Pre mix:
1 mashed banana
1/2 can of grape juice concentrate
14 oz. of apple sauce (large jars usually sell at 24 oz. so half of a large jar)
1/8 cup of molasses

Take your premixed ingredients and bring them to a boil on the stove, than remove from heat and let cool.
I'll normally freeze half of this and leave the other half in the fridge.

Mixing up the culture:
6 tbs. of pre-mix
2 tbs. of brewers yeast
4 tbs. of instant mashed potatoes
2 tbs. of white vinegar
2 tbs. of water

Water and vinegar may vary slightly depending on the humidity of where you keep your cultures and how well ventilated the cultures are. The idea is though to add even amounts of each. Once mixed let it stand for about 5 minutes, and if it's to thick add a little more water and vinegar.
Bakers yeast should be added to the cultures once the media sets in the containers. Between 5 to 20 granules or so is usually good.
From there I like to add coffee filters for the flies to crawl around on. I usually take 5 basket styled coffee filters and loosely ball them together to make one larger ball and place them into the culture and gently press it into the media a little. Once that's done you just need to seed the cultures with your flies.

This is actually the last recipe that Philsuma posted back on the first page. I've just done the breakdown to mix it up a culture at a time.

Hope this is useful