Penn State Spawn Lab Procedure for Making PDYA

To Make 1 Liter:

  • 250 grams potatoes; Do not peel. Scrub clean, cutting out eyes and bad spots
  • 20 grams Agar. Cut into 1/2" pieces.
  • 10 grams Dextrose, Anhydrous
  • 1.5 grams Yeast Extract

Rinse and drain cut potatoes twice with tap water and once with distilled water. Add 1 liter distilled water to the potatoes. Cook until potatoes are tender. Filter the potato broth through two layers of cheese cloth. Save the broth and discard potatoes. Add distilled water to broth bringing volume up to 1 liter. Heat the 1 liter of broth to a boil. While stirring slowly add agar, dextrose and yeast extract. Stir until dissolved, watch carefully or it will boil over.

Autoclave for 15 minutes at 121C.