Bag-end bread

Hey dobie! I brew my own kombucha; it's way cheaper that way and I know exactly what is in it. Basically, I boil 2 litres (quarts) of water then add two black tea bags and two green tea bags, and half a cup of sugar. Brew for ten minutes then cool it to room temperature (that takes quite a while, so I brew in the morning and make kombucha in the evening). I have a large glass brewer with a tap on the bottom. I draw off the finished kombucha, then top up the brewer with the newly-brewed tea. I usually do this about every 7 to 10 days, and always have a second healthy scoby  floating on the top (I remove the old one and either compost it or give it away, then brew the new batch with the new scoby). Does that help?

I think I'll start a new thread, asking people what they have used to either make poolish (or other pre-ferments) or for soaking grains. Lots of interesting flavours to experiment with!

Hmmm, let's see if I can answer them all!

1. I usually get rid of the 'old' (bottom) scoby, but I don't think it much matters. You can even cut or tear it into pieces (don't use a metal knife though) and just use part of it if you want. They're pretty resilient cultures!
2. I haven't checked the acidity, but I think it varies more by how long the brew has worked, rather than whether it's drawn from the bottom via a spout or not. If I leave it go for more than 10 days it's pretty potent, and if I leave it in a warmish place it will continue to ferment (even grow mini-scobies in the bottles!) and get fizzy. I usually draw it off into large bottles with the wire bale corks and put them in the fridge
3. I don't really 'feed' it (not like a sourdough starter), but really make a new batch every 7 to 10 days. I draw off and bottle all but about half a cup or so, then add another 2 litres of fresh-brewed tea to the brewing jug. You should leave some in (as sort of a mother culture :)) before adding the fresh tea
4. You might kill a scoby by any contact with metal, or by contaminating it with soap or other disinfectants. Actually, I just dug out a bottle that I hadn't used in a while. I thought it had been put away empty and clean, but apparently not. It had a small scoby in the bottom with no liquid at all! I don't know how active it would be but it smelled quite nice, really, and wasn't black and dead looking.
5. I keep all my kombucha 'pure'. If you want you can put a little flavouring in the bottom of a bottle (say, and inch or so of something like fruit juice, a bit of crushed fresh fruit, some candied ginger and lime, whatever) and then top it up with kombucha and leave it to a secondary ferment. I prefer to put fruit juice in a glass then top it up with kombucha and drink it fresh. The secondary ferment will make it fizzier and also stronger (and will pop the tops off the bottles if you leave it someplace too warm for too long!)
6. And yes, as I said I put it into bottles right after it's finished brewing (at 7 to 10 days for me, though you can let it go longer) and put them in the fridge.

It's good stuff; I drink it every day!

I haven't heard of any toxicity issues, though if your scoby has black patches or there is white or grey mold growing on the surface I would throw out the batch. I'm careful to use clean hands when fishing out the old scoby, and to not introduce anything but fresh brewed tea into the container with the scoby, but other than that I don't fuss too much. Oh, and the fruit flies love it, so I keep the brewer covered with an old finely woven cotton hankie.

If you use screw top bottles be very careful to check them for pressure. If it is still fermenting it can blow up a bottle pretty quickly! Especially if you introduce another source of food (e.g. fruit or juice).