I am using a Kombucha Brooklyn home brew kit. There are other kits out there (vs. individual ingredients which more experienced brewers may prefer), but for a first timer this kit is perfect.
Boil 4 cups of water in a large pot.
Turn off stove and throw your 6 (or so) tea bags into the water. Black tea is common for kombucha, but oolong, green, and white can be used (or even mixed) as well. Avoid herbal teas and Earl Grey.
Cover and steep tea for 20 minutes (but don't forget to stir the bags occasionally).
After 20 minutes, remove the tea bags and add in the 1 cup of cane sugar. Mix well.
Add 8 cups (.5 gallon) of cool filtered (or bottled) water to the tea. I probably shoulda used a larger pot.
Now that the tea has cooled down, pour it into the 1 gallon glass jar. It is important to remember that the jar, pot, and utensils should all be well cleaned so as to avoid the risk of contamination.
One benefit to using a kit is that your jar's label has the fill line marked (about 2/3 full). If needed, add more cool filtered water to the jar until your tea is at the fill line.
Place your thermometer strip on the jar to be sure the brew is below 90 degrees F. Temperatures above 90 can harm your live culture.
Perhaps the main draw of a kit, it comes with a ready-to-use SCOBY (Symbiotic Culture Of Bacteria and Yeast). The SCOBY is bagged in the fermented tea of a past brew; pour in both SCOBY and liquid.
There she is up close. Starter SCOBYs are referred to as "mothers", since the brewing/fermentation process results in a second "baby" SCOBY.
Cover the jar with the cotton cloth and rubber band, and make sure to pull the cloth taut. No lid is used, as the brew needs air. The cloth is mainly just to prevent anything outside from getting in.
Set the jar in a warm place (between 72-80 degrees F), away from direct sun light. After 7-14 days, a new SCOBY will be floating atop the brew. The tea will be ready to bottle in the 14-28 day range.
There is no right time to bottle. When ready, use clean hands to move the SCOBYs to a sealable jar with 1.5 cups of the tea, and save them in the fridge for your next brew.
Next brew, use both SCOBYs and the leftover tea. As a third SCOBY will form, dispose of the oldest keeping the younger of the two. For experienced brewers, this process can be kept going for years!
With SCOBYs in the fridge, bottle your tea into glass growlers and consider all the many fruits, spices, and flavors you can experiment with adding here. As a novice, I'd love some recommendations!
Let the bottled tea sit for 4 - 14 days (though it can store almost indefinitely). Store less times for a sweet tea, or more time for a sour tea (my preference). Enjoy!