It's been a while since the last time I wrote on this thread. I'm continuosly using freezing techniques learned here, and I'd like to report some considerations I made.
FREEZING PART OF LIQUID YEAST
Every time i buy a new wyeast pack I collect a part of the yeast the same day that i prepare my starter. usually I take a couple of vials with 18 ml each filled with the content of the yeast pack + 1,5ml of Glycerine. this allow you to use that kind of yeast at least 2 times. I don't want to continuosly reuse the same yeast because I don't think i can perform yeast washing in a proper way (and also because i want to be able to count the yeast cells (in a theoretical way of course). If 125ml of yeast pack has 100billions of yeast cells, each vials should have 12 billions of yeast (80% after freezing). with a couple of starters (0,5l + 1,5l with stir plate) I should end up with about 200billions of cells.
FREEZING DRY YEAST
Tried this few time with Fermentis S-23 and it work great! I only have to re hydrate yeast and fill vials with glycerine ( I use pressure cooker to sanitize everything). the only thing that I have to report is that for some reasons that I cannot explain this vials tend to produce some gas when they are opened ( I don't know why because it is just yeast and water + glycerine). So when I thaw it I have to let the gas out from the vials before putting them in the fridge. I use the fast thaw technic and then let the vials at 4°C to let the yeast settle at the bottom and remove as much liquid as I can.
Also tried to freezing yeast collected with top cropping, I've made a starter but then I decided to not using that yeast. the smell wasn't very good, beacouse I have also collected a lot of hops and proteins. I don't know if you are familar with the smell of krausen (try to skim it once ).
Thanks to everybody for the grat inforomations, this really improved my brewing process, and now that I also have a dedicated fermentation chamber I can brew every kind of beer wherever I want to!