Another newbie question!

[Jackieabz]

I'm making my kombucha in 3L batches. I'm just about to start my 4th brew. Could anyone advise on a few points please.
Is 30C/86F too warm for fermentation?
Should I remove/divide part of my scooby as it grows?
I'm hoping the white spots in the photos are not mould, they're just milky white and not furry.

Any advice really appreciated.

 

[Boer]

Hi Jackie, 30 C is 100% for fermentation because the yeast will reproduce up until 36C for the most dominant yeast strains (e.g. Saccharomyces, Zygo and Brett). You ideally want the temp a bit lower so your bacteria will eat the ethanol (produces by the yeast) a bit quicker to limit the alcohol production of the yeast.

 

[Jackieabz]

Thank you Boer! I usually try to keep it around 26C but I don't have a temperature controller so it is a little hit and miss. Your reply really helps.

 

[Boer]

And don't worry, your pellicle look really healthy (Although there is a unnecessary emphasis on the pellicle). The light white that forms is just the new "baby" that's busy forming. By the looks of it you have a really active fermentation- by looking at the bubbles on the edges of your container.

If you want to experiment more: try to do a fermenting batch without adding a pellicle.

 

[Jackieabz]

Hi again Boer, by pelliicle I take it you mean scooby. If I don't use it am I then relying on the natural wild yeast in the air for the fermentation as in sourdough brread? Sounds interesting.

 

[Boer]

So new brewers always refers to the pellicle that forms as a byproduct of fermentation as the SCOBY- but really the SCOBY is just the starter liquid that is much more richer in both yeasts and organisms. The only real function about adding a pellicle with a primary fermenting batch is you are suffocating the yeast earlier, so you are doing the bacteria's job quicker: (remember the bacteria forms a new pellicle as a byproduct of cellulose in order to limit yeast reproduction and start with fermentation. )

In other words- if you want your kombucha to have the right taste (nice acidity and effervescent), try to add a bit more of the SCOBY liquid (starter), you'll find that the new pellicle that forms will be a thin but strong layer as the bacteria will almost be more dominant than the yeast so any glucose that gets formed by the yeast's ability to brake down sugar into glucose and fructose will produce acetic and gluconic acid.

That's the interesting thing about Kombucha: both the yeast and bacteria work together and against each other to form this wonderful beverage! I find it fascinating!

I tried to explain it as simple as possible but If something is clear just shout!

Hi again Boer, by pelliicle I take it you mean scooby. If I don't use it am I then relying on the natural wild yeast in the air for the fermentation as in sourdough brread? Sounds interesting.

 

[Boer]

Hi again Boer, by pelliicle I take it you mean scooby. If I don't use it am I then relying on the natural wild yeast in the air for the fermentation as in sourdough brread? Sounds interesting.

Interesting question about airborne yeast. So the most common strains found in Kombucha are not airborne (S. cerevisae, Zygo etc.) but there is one strain that has been known to reproduce trhoughout air and that is brettanomyces but if you use a brett ferment you'll probably have a kombucha with off flavour. (Brett is used sometimes in Beerbrewing also)

So thats why it is recommended to always use some of your previous batch and add it to your newest batch so you dont only have a brett ferment.

 

[Jackieabz]

Very helpful information, thank you so much!