Take a moment to picture a person dressed in a white lab coat surrounded by stainless steel surfaces, glass beakers and test tubes.  I am not that person!  My goal is to make growing potatoes from true seeds easy and accessible to the home gardener.  Extracting TPS from potato berries can be as simple or as complicated as you want to make it.  I am aware of different methods of extraction that involve blenders, bleach, tri-sodium phosphate, fermentation etc. but I don’t use them.  Below are two methods of extraction that work for me.

Simple method (for just a few berries):

1. Cut soft potato berry in half.
2. Gently squeeze seeds and pulp on to a sheet of paper (construction paper works well).
3. Push seeds and pulp around the paper with a knife (or another flat edge) until the paper soaks up the liquid from the pulp.
4. Use your flat edge to separate the seeds from the remaining pulp.
5. Spread out the seeds on another sheet of construction paper and let them dry for several days.
6. Store seeds in a cool dry place.

Slightly more complicated method (for larger amounts of berries):

1. Cut soft potato berries in half.
2. Gently squeeze out seeds and pulp into a bowl that is half full of water.(Use your judgment to get the greatest amount of seed with the least amount of pulp.  If I have a lot of berries, I will leave straggling seeds in the berry to make separating seeds easier.)  Discard the berry skins.
3. Break up the seeds and pulp as much as possible. Good seeds tend to sink and empty ones will float.
4. Swirl the water in the bowl and let the seeds settle out. At this point, most of the seeds should be gathered at the bottom and the pulp will be suspended in the water.
5. Slowly pour off the water while attempting to leave most of the seeds in the bowl.(If you are worried about losing too many seeds, you can pour the water into a strainer lined with a paper towel or coffee filter and rescue the seeds from there.  I don’t worry about it.  Pour slowly!)
6. Dump the seeds on to a sheet of paper (again, construction paper works well).
7. Push seeds around the paper with a knife (or another flat edge) until the paper soaks up the liquid.
8. Spread out the seeds on another sheet of construction paper and let them dry for several days.
9. Store seeds in a cool dry place.

I strongly recommend that you work with one variety of potato berries at a time and label the seeds as soon as you finish extracting them.  Keeping potato varieties separate is the best way to reproduce a successful result in the future.