I am going to purchase a yeast starter kit (stir plate, flask, etc.) and wondered what size flask do most of you use. I brew mostly Med - High Gravity Ales but occasionally brew a lager which may require a lager flask.
Thank you,
Rob
Usually a 2 liter. I also have a 1 liter and a 5 liter for use as needed, but the 2 liter is my go-to. The 1 liter is used mostly for rehydrating.
I use a 3 liter flask for a 2 liter starter.
although I no longer use a stir plate, when I did I used a 1 gal. glass apple juice jug. Much cheaper than a flask.
Difficult to sterilize a glass jug.
You can boil an Erlenmeyer.
You can leave an Erlenmeyer in the fridge for a few weeks without risking contamination, if everything was clean to begin with.
5L flasks are helpful when capturing yeast for repitch.
Purchase the flask or flasks that properly fit your stir plate.
I built my stir plate to match the size of my flask. ;D
This^^^
I use a one-gallon jug for the shaken not stirred method of yeast starter, or as it’s sometimes called, the vitality starter.
Same here. And contrary to other comments such one gallon jugs are no more difficult to sanitize (not sterilize) than any other similar piece of equipment.
You can’t sterilize something without an autoclave.
For all practical purposes, a clean flask that boils water for 15 min is sterilized.
The key word is “clean”; if it is perfectly clean, you don’t need the boiling. If it isn’t, the boiling won’t kill all spores.
Clean to the eye is not clean to the microscope.
Before disposable syringes, humanity had sterilized by boiling for many years.
We all know the spores argument, which is technically correct, but the possibility that a spore is present and remains viable in a boiled flask is orders of magnitude less than in a sanitized jug.
5 liter. I like being able to boil the flask on direct heat (you don’t need a diffuser) using a foam stopper. If I want to cool it fast I can immerse in cold water. I will remove the foam for a quick shake to aerate. I’m sure I’ll get flack about direct heat and direct immersion so I will address the obvious. You should heat and cool relatively slowly, borosilicate glass can take it, but don’t push it to extremes.
Fortunately, sterilizing it was unnecessary.
I so rarely make a starter anymore…I just repitch, often directly from primary to primary. It takes some coordinating brew days, but really makes the availability of super fresh yeast a certainty. As to Ehrlenmeyer flasks, I used 2 liter size flasks most frequently before moving on to gallon jugs and SNS approach to starters…but I now directly repitch when I can.
this is important, because i am planning on using my yeast starters for direct injection into my bloodstream, so they must be medically sterile.
i wish i was just homebrewing 5 gallons of beer that will be gone in a relatively short amount of time, but thats not what people are on this forum for.
Exactly. Boiling is not sterilization. Spores take time to germinate which is why boiling can render something temporarily sanitary but is not acceptable for storage.
Luckily, sterile is not necessary when dealing with the quantity of a yeast pitch (i.e. not growing from slants). This is why you can reuse yeast from a previous batch, fermented in a non sterile fermenter, for a long time in the fridge and the limiting factor is yeast health, not contamination.