Step 3: Germinating your brown rice: about the hot plate
You need brown rice to make GBR. White rice has had the hull removed, which means that it is no longer capable of germinating.
GBR is made by soaking brown rice in warm water (30-40 C, 86-104 F) for up to three days. You can soak it for a much shorter time; what you'll want to see is the sprout start to emerge from the grain of rice. Research has been done on GABA production in Japan that relies on a 16-hour soak cycle.
For equipment I use the pot from one of my rice cookers, the cheapest hot plate I could find, a dial rheostat for controlling the power into the hot plate, and a home medical thermometer.
For this setup, having a cheap hot plate is essential. Adjustable ones sold in Japan start at 80 degrees C for keeping food warm, and generally have a stop at 100 (for boiling water) and 200 (for frying in oil). This is way too hot for sprouting rice! Limiting the flow of electricity into one of these will simply make it not work, as the electrical components are designed to work at regular outlet voltage. Try to find a recycle shop somewhere and pick up the cheapest one you can find; it should be fine. If you're not sure, take it apart and make sure that it's just the plug wires going straight to some kind of metal plate inside.