look up a recipe for PDA (potato dextrose agar- fungal growth medium- used by the big guys). essentially you boil sliced potatoes for about an hour, then you add some agar (from a healthfood store; solidifying agent). ive sourced some petri plates, but you can use pint mason jars. pour a thin layer of the media into your plate or mason jar. hit the top of the media with a quick blast from a flame to sterilize the top and pop any bubbles. replace the lid, let the media solidify and store inverted.
to inoculate the media, get a loop of wire and flame it until its glowing red hot. then let it cool briefly. dip the loop into what you want to culture and then streak the top of the media. replace the lid, store inverted at 68-70F. you should see colonies growing with in 24 hours. you have now isolated your own yeast.
as for a starter media, if you have any experience canning jams and jellies. Can some wort the next time you brew a batch, i usually can 1-3 quarts when i brew. so i have starter for the next batches. i found 1 quart can make 2 starters.
to make starters, when you have your yeast colonies isolated and your wort starter all made up. use you flamed loop and scrape up one of your colonies, trying not to collect any of the PDA media, then dip and mix it into your starter media. add an air lock and ta-da! starter inoculated, store at 70F for a few days. you can increase your concentrations of yeast in the starters if you acquire a stir plate and stir bar
