Alternative to stir plate for yeast starter (and erlenmeyer flask)

I use a 750 ml bottle, sanitised aluminium foil and a rubber band. Keep aerated by stirring it gently, occasionally during the first 12h; I stir every 6th hour or so. After 18-48h I use it or refrigerate it for later use.

I use White Labs instructions for reference, no matter the brand of yeast I buy.

Cheers!

You could build a stir plate - you probably already have most the stuff laying around.

Step 1: Gather a computer fan, power supply, stir magnet, and neodymium magnets and 2 L mason jars.

Step 2: Glue 2 neodymium magnets to the computer fan facing upward, with one + side up, the other - side up. The diameter should be the length of your stir magnet.

Step 3: Connect the power supply to the fan via the molex connectors and jumper the green wire to the black wire. The fan should spin, if you want to use a on off switch you should wire it in here, between the green and black wires from the motherboard connector. https://www.silverstonetek.com/downloads/QA/PSU/PSU-Paper%20Clip-EN.pdf

Step 4: Sterilize everything. Then, throw the magnet into the jar, set the jar on the fan to drive the stir magnet.

Step 5: Add water, yeast, and sugar at the amounts recommended by white labs.

A stir plate does two things. Both can be done manually by swirling your vessel.

1. Provides the yeast a good amount of oxygen.

2. Reduces yeast lost, from lifting out with krausen and drying on the sides.

Put your starter in a common place like in the kitchen and swirl of whenever you walk by.

Erlenmeyer flasks are unique in that they are made of Pyrex and can be used to boil starter wort in on a gas burner. They also have a flat bottom for use on a stir plate. The tapered shape does little to aid a starter.

Any food grade glass vessel with an opening foil can cover is fine for a starter if you boil and cool wort before adding it to the vessel. 1 gallon wine jug work great and is much cheaper than a 5000ml flask. Mason jars are perfect for small starters.

Thrift stores usually have old coffee pots which work really well. They too are heat safe and have flat bottoms. If the pot has any plastic just remove it. Some may have a warning not to boil liquid in them, but in my experience this is because they have some plastic handle etc. I have used these over gas flames and in the microwave to boil wort water.

I Use various size canning jars, I have the, from .5L up to Half Gallon. I only fill them up Half way to 3/4 full. And when making the starter, I leave the lid partially screwed on.

Then during the process, every time i walk by Open up the jar swirl Then I spend about 10 seconds shaking it with the lid on Tight. then crack it.