Hi, a word or two about my yeast cultivation and storage. On brewday I have a 2 litre flask of yeast in diluted dme which hopefully has a good population before it has reached full krausen.
I sterilise a kilner jar and lid by boiling in water with a teaspoon of clear malt vinegar. Making sure the big conical flask contents are well distributed, I carefully fill the kilner to the neck of the jar.
The lid is then replaced and put at the front of the fridge. Every week for a couple of weeks, I unscrew the lid enough to release any co2 that may have built up
I add a splash of yeast from my 2litre conical flask to a 1 litre conical. This is for a fast fermentation test. This is then tip up with 300ml of wort, when it is ready.
Next the remainder of the yeast solution is cold crashed if there is room in the house fridge or if the brew fridge is available and cold.
On brewday, when my beer has been brewed and is at the right temperature for pitching (or preferably 2deg c below), I pour away the tip clear dme down the sink being careful to unsettle the yeast settled at the bottom. I keep enough dme solution in there to disolve the yeast for an easy pour into the fermentor.
Precautions whilst handling yeast:
Keep all doors / windows shut
Clean surfaces, maybe wipe with ethelene.
Boil dme solution for 10 minutes checking to stop boiloverz
Cool to pitching temperature
Place steralised stir bar in conical flask, cover with steralised piece of silver foil.
Use a stick lighter for a moment to the mouth of the kilner jar and conical flask to neutralise any dust particles that nasty be present