FGRS: protocol


Making YPD Plates

Last Updated

February 12, 2010 7:04 AM


YPD medium is a complex medium often used for growing S. cerevisiae. It is composed of yeast extract (for vitamins and other nutrients), peptone (broken down proteins), and glucose (the energy source for the yeast). After the solution is prepared, it is autoclaved so that it is sterile when used.


  1. Graduated Cylinder

  2. Nanopure Water

  3. Flask/Bottle

  4. A weigh boat and 3 spatulas

  5. 10g Yeast Extract

  6. 20g Peptone

  7. 20g Glucose

  8. 20g Agar

  9. Aluminum Foil

  10. Stir Bar


  1. 1.Measure ~700ml nanopure water using the graduated cylinder and add to flask. Add stir-bar and begin stirring the water at ~medium speed.

    Note: The graduated cylinder is used instead of the flask because it is more accurate than the cylinder, so ignore the apparent discrepancy you will see when the water is added.

  2. 2.Place empty weight boat on the balance and tare it. This makes the balance think there is nothing on it, so you will only be weighing the ingredients.

  3. 3.Weigh yeast extract, and add to flask.

  4. 4.Repeat with peptone and glucose. Weigh each component separately, but re-use the same weigh boat.

  5. 5.Add agar when other ingredients are dissolved (no powder can be seen).

  6. 6.Pour solution (NOT including the stir-bar) back into the graduated cylinder.

  7. 7.Bring the volume up to 1000ml using nanopure water. This ensures that the final volume is 1000ml, including the ingredients added.

  8. 8.If you need to aliquot the media into smaller flasks, do this now.

  9. 9.Tear off a small piece of aluminum foil and cover the top of the flask.

  10. 10.Place a small piece of autoclave tape on the aluminum foil and autoclave.

  11. 11.If you are unsure about how long to autoclave or want to make sure you prepared the medium correctly, please ask a staff member!

  12. 12.Cool to 50 °C and carefully pour into sterile, labeled petri dishes aiming for speed, accuracy and the least amount of bubbles.

  13. 13.Dispose of excess media in the gel bucket before washing glassware. Do NOT dispose in the sink as this could clog the drain.

Developed By

Andrew Hertsenberg & Monica Noori