Hi to all, I just wonder how are you kombucha doing? I hope that they are well and they prosper. For the ones who got their cultures on the OHM2013 and prepared 0.5 l of brew with 10% (w/v; 50 g) of light brown or dark brown cane sugar and 0.5-1% (w/v; 5-10 g) of black tea, the time of making larger batch is coming. For the ones who got their SCOBY's recently, I recommend to make the first batch as described above and let it ferment for 10-14 days so the mother (SCOBY) gets thicker and is more easy to work with, the brew however is too acidic to drink but should be feasible for vinegar. The SCOBY harvested after such period should be fine to ferment up to 5 l of brew easily, it will take few weeks of brewing till the mass of the SCOBY stabilizes and the performance is more repetetive.
For the next brew I would suggest probably 5 l wide mouth jar and aim for culture volume (Vc) 4 l. The concentration of ingredients for the growing media (brew) should be around 5-6% (w/v; 200-240 g) of cane sugar (light brown or dark brown) and 0.5-1% (w/v; 20-40 g) of black tea. This would leave you with +- 1 l of air in the container, still the culture has to be protected by some cloth so it can breath but the insect can not get in - make sure to fasten it by some rubber string.
If fermented at room temperature ranging from 20-25C, you should be ready to harvest between 5-8 days optaining a lighter style of kombucha, suitable for drinking 0.5-1.5 l per day of consumtion should be OK. You need to make new media, transfering the mother (SCOBY) in it and straining and bottling the old brew. That is a good moment for adding variety of flavours, be careful about the ones with high concentration of sugars - they will go really fizzy and can run from the bottle or even explode. Simple one (whic I truly dislike but many love) is nettle flavour. You get either fresh or dried nettle leaves and make a strong infusion by boiling (for 4 l, I would suggest 0.5-1% (w/v; 20-40 g) of leaves simmered for 5 min or so in low volume of water, maybe around 200-300 ml). Strain the nettle out and add the liquid to the brew, do not worry about the temperature the total volume will buffer it. When happy with flavour I recommend to strain the brew completely through fine sieve so you get rid of small pieces of SCOBY which are not liked by many, also it slows down the creation of the SCOBY's in the new bottles.
If you like your drinks to be fizzy, I recommend to bottle them bit sweeter than you like, make sure the lids are really tight so the carbon dioxide which is being produced doesn't escape and keep them fermenting at room temperature for one to three days (good trick is to bottle one bottle in plastic, so you can check by touching what is the pressure, it is hard to say if all the bottles are in glass). When happy with the fizzines, transfer the bottles to cold (below 6C) and keep them maturing for week at least to improve the flavour, but you can drink directly too.
Well that would be a bit of info please do ask if you have questions and add your suggestions! It may take me a bit of time to respond, I'm giving workshops and exchanging cultures in Prague hackerspace Brmlab now
https://www.brmlab.cz/project/food_hacking#bio-culture_exchange
(got starter from Dan to make my own tempeh :-)))
and I will be leaving for Korea on Saturday, I finally got working visa as a fermentation expert :-)
Talk to you all soon, and below are few links which should help you to progress on kombucha and other ferments.
Sincerely from Brmlab, Prague,
Frantisek Algoldor Apfelbeck
Links
https://www.noisebridge.net/wiki/Recipes_and_Manuals
https://kvasirdiary.wordpress.com/
http://www.wildfermentation.com/forum/
biotechnologist&kvasir and hacker
http://www.frantisekapfelbeck.org
"There is no way to peace, peace is the way." Mohandas Karamchand Gandhi