sprouting vesselI purchased my mung beans at the Asian market. A 12 oz bag costs me 99 cents. You want to make sure that the beans you intend to sprout are food grade. If you'd like, you can buy organic beans from a supplier that tests their stock for E. Coli and salmonella. Since commercially produced sprouts have been identified as a major source of food born illness, you want to be fairly confident in your seed source. Another option is to treat your seeds before you sprout them. To do so, heat a solution of 3% hydrogen peroxide (about 2 and a half tablespoons of hydrogen peroxide for every 5 cups of water) to 140 degrees F. Monitor and maintain at this temperature using a kitchen thermometer. Using a small fine-mesh strainer, immerse the seeds into the solution and swirl them around every minute or so for 5 minutes to ensure uniform treatment. Remove the seeds and rinse under running water for 1 minute.
Next, you want to soak your seeds in water for 12 hours at room temperature. Your seeds will begin to drink and plump up during this time. The next morning, drain the seeds and remove any debris or hard or discolored seeds. Then rinse them well under running water.
mung beans after 12 hours of soaking
Place the seeds inside the sprouting vessel, shaking it a bit to get them somewhat level. Place the smaller lid directly on top of them and add your weight. Mung beans sprouts grow longer and thicker if they are subjected to pressure. You can experiment with the amount of weight to use but I have read that you should use 0.5 ounce of weight for every square inch of surface area inside your sprouting vessel. Also, you can use practically anything as a weight (as long as it's sterile). I used a couple of ceramic ramekins of varying sizes. Place the sprouting vessel inside the larger container and cover with the outer lid. Keep your sprouter in a dark corner of your kitchen counter.
You want to rinse your seeds 2-3 times a day for the first few days. It is important that your seeds do not move when you do so as you want them to form a secure mass as they grow. Again, this will help you get longer, thicker sprouts. I rinse by removing the sprouting vessel, adding enough water to the larger container to cover the seeds by an inch or so, then slowly immersing the sprouting vessel into the water and lifting several times to rinse. Repeat this for the first 3 full days.
On the 4th day, cut down on rinsing to once a day for the next 2-3 days. When you do so, keep the seeds immersed in cool water for 15 minutes. Doing so encourages the sprouts to really size up. By the 5th day, you can also remove the weight. The sprouts should be firmly in place by then and should be ready by the end of the 5th or 6th day. Final tip: to separate the green skins from the sprouts, toss the sprouts gently in a large bowl with your hands. You will notice that most of the green skins end up at the bottom of the bowl. Then place the sprouts into a sink or large bowl filled with cold water. The sprouts will float and the skins will sink to the bottom. Run your sprouts through a salad spinner before storing in the fridge as they keep best when dry.
Update: I forgot to mention- you might want to make one slightly larger hole about a quarter inch in diameter at the bottom of edge of sprouting vessel. This will help drain the water during rinsing. Cover the hole with your finger when measuring your dry beans. After soaking, they should be plump enough not to fall out.