[DIYbio] Re: Has anybody done a scoby project similar to The Thought Emporium

You also need to be very careful to clean all containers and utensils. And use a freshly laundered dish towel or a paper towel to cover the mouth of the jar, so the culture can get plenty of air, but no mold spores can get in. I usually use a roll of paper towel, discard the outer layer of paper, and cover the mouth of the jar with at least 2 layers of paper. I don't recommend using cheesecloth - the pores are far too large, and you'd have to fold over the cloth multiple times to even keep our fruit flies, let along mold spores.

To grow a large sheet in a large plastic tub, some people seem to trust the gap between the tub and the lid to provide oxygen while keeping out mold and flies. I wouldn't - if the lid closes tightly enough to keep out a tenacious fruit fly, it likely doesn't provide as much air as the culture would prefer. Last time, I simply put 2-3 layers of paper towel on the rim, and pushed the lid down on that, both enlarging and filtering the air gap. Next time, I'm considering just cutting some big holes in the lid, and covering them with a cloth filter. 

Most importantly- don't leave the tea or brewing kombucha open to the air for any longer than absolutely necessary. I would put the sugar, teabags and boiling water in the container you'll brew the kombucha in, and let the tea cool down in there. That way, you disinfect the container one more time with the boiling water, and you avoid having to pour a lot of sweet tea which seems like a great occasion to suck in some contaminants. Use a container made out of glass or transparent plastic, so you won't need to open the lid during fermentation to check for progress and any signs of contamination. I wouldn't recommend using a ceramic crock pot to brew kombucha, because you wind up having to risk introducing contamination just to check for contamination! 

Patrik