Dissolve the sugar in a small amount of hot water in the half-gallon jar. If you want to make the entire half-gallon you will need to use ½ cup of sugar.
Once the sugar is completely dissolved, fill the jar hallway with cool filtered water. Make sure the water is not warm, this is important. The water must be room temperature.
Now, add the water kefir grains to the jar.
Cover the jar with either a towel, cheesecloth, or coffee filter and secure with a rubber band. I prefer using a coffee filter. You need to do this so bugs, dust, and little kids don’t get into your water kefir as it is fermenting.
Allow the water kefir to sit on the counter or table, undisturbed, for around a day or 2. Try to keep the jar in an environment that is around 70 to 75 degrees F (21 C to 23 C).
After about 48 hours, strain the kefir grains through non-metal mesh strainer and catch the liquid into another container. I like to use 2-quart sized jars.
Restart the entire process by dissolving more sugar in filtered water, adding my cold water to the mix, and placing your kefir grains inside.