Dave and someone else (sorry, Alzheimer settling..) suggested the fermentation method for tomato seeds.
Good old Dimitri tried the trick for mulberry seeds that a few people asked for. Guess: yakky frothy smelly fluid with ALL seeds on the top! And now how do I separate the seeds from the ****?
Yakky frothy smell? Sounds like my kitchen right now! :-) This means that the fermentation process is well underway.
Only the good seeds will sink, however, and the non-viable seeds will float. If all your seeds are floating, my only guess is that these seeds simply are not viable. I did some searches on Google and found that Mulberry fruits benefit from fermentation, so it looks like you're doing everything right.
The rule of thumb is that if it sinks ,it's good...if it floats,it's bad. That ain't actually so for every variety.
I don't know about mulberry seeds..but that may be what is going on. Try stirring the mess and see if you have any sinkers. If they all still float,my suggestion would be to pour the stuff through a strainer and wash the seeds under running water. This won't get rid of your dead seeds,but it will clean the whole mess.I'd wait till the fermentation time was complete. After cleaning ,see if some sink then.
If they all float...do a germination test before you send them out to people. Then you'll know for sure.
Also... I have noticed that the seeds from tomatoes that I have fermented sometimes (depending on the variety) will float for the first couple days. After a couple of stirrings, they finally settle at the bottom.
Once the process is complete, I make sure to put the seeds in a new glass of clean water. Any floaters at that point are discarded. But, again, this is my experience with tomatoes, not mulberries. Keep us posted Dimitri.
The seeds probably have a gel covering that lead to early floating; as fermenting works through the gel, the viable seeds should settle. Hope you started with a pretty thick puree and not too much water. Given warm temperatures, the process ought to be over in 4-6 days.
Alas, poor me!! What a tragedy have I gotten my wardrobe into !! A tiny little corner where no one would find it and start complaining, to place just a little glass with some seeds in it... and then froth, and smell, and yakyness itself!! Alas!!
Now I must find a bigger glass, more water, shake but not stir, more froth, no soda, no ice...what a potion of secrecy and gardenial ecstasy am I preparing?? All they asked me for was a few seeds... I had better eat the mulberries and spit the seeds out!!
And then, some thinking: Some people here in DG told me to buy dry dates if I wanted to plant the pips to make palm trees, so I went to the mulberry tree again, and instead of picking fresh sweet juicy mulberries, I pulled the dried ones off the pavement, and they are going in the mail tomorrow!! Alleluja ! Ole ! Whatever !!
PS: The frothy lot will have to complete the course and if you see me in the winter and think my trenchcoat smells of something, I will be rude.
Also, the people at the village saw me picking the berries from the ground and since I am considered a serious doctor, they now suspect that I have a peculiar cure (ointment??) for arthritis, containing mulberries..