Media (see below and protocols page for recipes)
    Yeast are commonly grown in the laboratory using two general types of media, rich media (YePD) and synthetic media (minimal media).  Rich media is formulated to supplies yeast with ample metabolites, including a nitrogen source and a carbon source, usually glucose but can be varied.  Synthetic media can be formulated to be complete or selective and is more of a 'bare bones' type media, containing known types and amounts of carbon and nitrogen sources, essential minerals and vitamins as well as all or some of the necessary amino acids and nitrogenous bases, depending on the particular genetic background of the strain being used.  To make media selective, a drop out approach uses a minimal media base, and adds all the potentially needed amino acids and nitrogenous bases except the one(s) for which selection is desired.  It is possible to have double-drop-out media or to leave out even more components when desired. 

Growth 
    Yeast are normally grown at 30^oC and can be grown on agar-containing plate media or in liquid media.  Yeast grown on plate media can be stored at 4^oC for a month or two (wrap in parafilm helps; restreak as necessary) as a for use in ongoing experiments.  If the plates contain rich media, the yeast should be regrown every six weeks.  If the plates contain synthetic media, the yeast should be regrown every four weeks.   Liquid cultures are can be grown in culture test tubes or flasks and are usually accompanied by rolling or shaking to keep the yeast in suspension and the cultures well aerated for optimal growth.  Progress of growth us usually monitored by the absorbance reading at 600 nm in a spectrophotometer; dilute cultures in media if OD is over 0.8 to get an accurate reading.  When yeast are grown in a media containing a fermentable carbon source (i.e. glucose), they grow exponentially over time until the fermentable carbon source is depleated (see graph below).  This point is the diauxic shift and marks a slower but still exponential phase of growth that utilizes the non-fermentable carbon sources (ethanol) produced by the yeast.  Once yeast stop growing, they have by definition entered stationary phase.  Most laboratory experiments are conducted using yeast grown and harvested in early log-phase growth (OD₆₀₀ = 0.5 - 1.0) although this can be altered to serve the purposes of the experiment. 

http://cmgm.stanford.edu/pbrown/explore/curve.html

Getting started 
    Yeast are normally cultured in liquid for laboratory experiments.  An overnight culture is started in the appropriate media by innoculating the media with a 'glob' taken by a sterile applicator stick from a petri plate stock of the desired yeast strain.  This liquid culture is placed in a roller or shaker overnight at the appropriate temperature.  The following day, this overnight culture is used to innoculate liquid cultures for log phase growth.  The amount of liquid overnight culture used to innoculate the log-phase culture depends on the conditions for growing the yeast, but generally the yeast should undergo AT LEAST two doublings or more before collection for the experiment (i.e. they should start at OD₆₀₀ 0.1 if the cultures are to be collected at OD₆₀₀ 0.4).  It is always easier to innoculate with less than needed and add more innoculum than it is to deal with having innoculated the log-phase culture too heavily at the on-set.  Consider taking the OD₆₀₀ reading after the first attempt to verify any 'guesses' you have about how much to use, expecially when setting up multiple similar cultures.  The log-phase cultures are then placed in a roller or a shaker at the appropriate temperature.  The state of their growth can be monitored using OD₆₀₀ readings until the desired reading is obtained.  The yeast are then collected by centrifigation for the purposes of the experiment.

Culture tips 
   Healthy laboratory yeast strains have a dividing time of about 90 minutes in rich media and 140 minutes in synthetic media (both with glucose) when grown at 30^oC.  The rate of growth will be different if less easily metabolized carbon sources are used. 
    The rate of the culture will be enhanced with good aeration, so shaking vigorously can be of great help.  The best aeration (using normal microbial culture equipment) comes from using an orbital shaker, where yeast are often shaken at 150-200 rpm, or even 250-300 rpm for very good aeration.  Another way to enhance aeration is to make sure the surface area of the interface of the media and the air is maximal.  Flasks optimize this when they are used with media in volumes of only 10-20% of their total capacity.  Full culture tubes of course have the least aeration. 
  

*add 80 mg of adenine sulfate if you're growing ade2 strains

YPGE

*ethanol is a non-fermentable carbon source, so YPGE can be used to test for mitochondrial defects

Synthetic minimal Dextrose (SD)

Complete Mix for Use in SDC

*please note that individual ingredients may be left out to make "drop-out mix" for use in selective media (SDC-ura, for example)

Methods in Yeast Genetics: A Laboratory Course Manual

by Kaiser, Michaelis, and Mitchell

Cold Spring Harbor Laboratory Press 1994