Yeast starters will jump-start your fermentation, but you can supercharge the process with a stir plate, which uses a spinning magnet to keep the liquid in constant motion. This ensures that the yeast cells don’t settle, it keeps the cells in contact with wort while minimizing the concentration of “poisons” such as alcohol and CO2, and it exposes the starter to a regular influx of oxygen.
You could buy a stir plate for as little as $45 (or easily spend more than $100), but it’s fairly simple to build one. You might even have many of the necessary parts around your house already.
Parts List
12V DC computer fan
9–12V DC power supply
25 ohm potentiometer with a knob to provide a variable resistance
Toggle switch (12V SPST)
Steel washer to serve as a spacer for the magnets
Rare earth magnet(s)
1 short jumper wire
Mounting hardware for the fan:
- Four 2" (5 cm) machine screws
- 8 nuts to fit the screws
- 4 metal washers to fit the screws
- 4 rubber washers to damp vibration
Container
1" (25 mm) plastic-coated magnetic stir bar
Flat bottomed container or flask, 1–2 quarts (1–2 liters)