Kombucha losing ability to make tea fizzy

[abcd]

Hello,

I've been brewing kombucha for a few months now, using only green tea and white sugar - something very simple for me to "feel" how the culture behaves.
I started with a tiny baby; it grew fast and produced amazingly good and very fizzy kombucha.
After a few months the mother has developed and has now lots of layers; however I've noticed that the taste of the brew has changed a little - the tea now gets more acidic and much less fizzy than it used to be.
I'm thinking I should remove the old layers and keep only the white, top layer, which sits at the air / liquid interface, to restore the brew to its glorious youth.
Any thoughts / return of experience?

Thanks!

[abcd]

So - that's done. I've removed all the bottom layers (6 cm, at least), and kept only the top, white slice. Everything looks fine - a new layer is already forming on top of the brew, and bubbles are appearing, meaning that I haven't killed it. I'll report here on what happens next (more carbonation or not?), but if any of you has observations to share, I'll take them!
Cheerio

[abcd]

Bottled and tried the new batch, and it's not any fizzier. It tastes better though - it's subtler and less pungently vinegary - but not bubbles.
I know that some of you leave the bottles somewhere warm for a few days before drinking, but I've never done that and in the beginning it was fizzy enough after one night in the refrigerator!
Any thoughts?

[Shimmerlow]

So sounds like it could be a few things:

First, I think it was a good move the keep the younger, to middle aged layers of you SCOBY going for making your KB. The older thicker, darker layers likely lose some of their vigor and the balance of Yeast to Bacteria gets thrown off to one side or the other, but the younger layers toward the top are healthier. Remember though that this is a living organism and you are watching generations of life cycles happen before your eyes so to speak- after time I think that could also change the taste of your brew a little bit. You might try and use a fresh/new bottle of starter tea instead of your current brew. Buy your favorite brand at the store or borrow some from a friend that has a great batch going. These "new" organisms can revitalize your colony and bring fresh genetic material to the party.

As for a Secondary fermentation cycle after bottling your KB- give it a try. Its a science as well as an art. I have been trying different flavors out lately. I had great success with Pomegranate Cherry Juice and dried cherries, Lemon and Ginger (fresh ginger and lemon juice), etc. The key is to introduce some fresh sugars to your brew and then let it ferment a little longer under pressure. How long? I have read that some people are getting high levels of carbonation after 12-18 hours, while others take 2-3 days. Its really going to depend on the amount and type of sugar you use (I have read that yeast likes complex sugars more than simple natural sugars, but that the bacteria feed better on simple sugars), the temperature where you are letting the bottles ferment (Yeast likes warmer temps 80 degrees and up, but the bacteria like a little cooler temps like 75 and and a little bit lower) , and the strength of brew itself (i.e. does it have a strong culture of yeast).

Hope that helps.

[abcd]

Hi Shimmerlow,

That helps a lot, thanks!!
I had an inkling that "something" might have deteriorated since carbonation is now much less noticeable (it is indeed almost flat) but as you say, the scoby is evolving!
Trying with fresh tea brewed somewhere else is also a great idea. I've always seen only one brand around here, which by the way is not fizzy at all, but I'll try that, and will also experiment with second fermentation (so far I had tried without adding any sugar, just filled up a bottle and let it in a warm room for 24 hours or so - I have a lot to learn on that subject).
At the moment I'm also experimenting on tea strength - my current batch is made from a much stronger (that is, longer brewed) tea. I'm pretty sure that can influence the final taste and fizziness and I'll let you know how this one turns out.

Thanks again,
Cheers!

[kindalooney]

I would encourage you to experiment with secondary fermentation. I have found it easy, interesting and the best way to create reliable carbonation. I usually use fruit juice in about an 80/20 'bucha/juice ratio, which provided the secondary sugar you are going to need to make pretty bubbles. I have also used raw fruit...blueberries worked well for me, just a few in the bottle before capping.

You are going to need a way to safely cap the bottles, wire bale stopper bottles are great, recycled Grolsch beer bottles, or commercial EZ-Caps from your local homebrew store. You also can buy a capping tool, blank caps and just collect longnecks.

As for time, I leave mine about a week to ten days, but that does vary with temp. In the summer, it goes faster, in the winter longer. After that, putting them in the fridge will generally slow up the fermentation. As for carbonation, if I pour a pint down the center of the mug, I'll get a pretty 1" head that holds up like a good beer.

[abcd]

I'll try that! The amount of carbonation you get is truly impressive...
My current batch is getting ready and I've got a few blueberries left at home, so I'll try that first - I already use Grolsch bottles for kombucha and kefir, they are the best I could find.
My only wonder is about taste, as I really like the taste of pure kombucha, sometimes with just a spot of powdered ginger - I usually don't like much sweet beverages so I'll have to experiment before I find the right amount of sugar to add.

Thanks again for the many pieces of advice,
Cheers!

[Nerium]

I am in the process of fermenting my very first batch of kombucha from a piece of scoby that I obtained from my local farmer's market. It is Day 6 and I haven't really noticed that the brew is fizzy. Should it be fizzy at this stage? Does it take a few batches before I'll see something like that? I've got what I think is a scoby forming, but no bubbles. Any thoughts?

[Fubar]

Carbonation happens when bottled. Kombucha is ready to drink immediately, but storing the bottled kombucha for a month or two will give you will give you an even better drink. This kind of bottle conditioning can improve the flavor as any home wine brewer will know. The sugar continues to ferment a little, giving you lighter, drier taste and producing more fizz.

[abcd]

Hello,

I tried a short second fermentation - I added a few blueberries to a bottle of kombucha (a recycled Grolsch bottle) and left it alone for 4 days in the laundry room which is the warmest room in my flat. With the hot weather we had recently, it was > 30 C inside, which I'd say is good for fermenting stuff!
Perhaps 4 days is not enough, but when I opened it this morning, I was disappointed - nothing, not even a bubble! It tasted good - quite tart and even a bit "drier" than it is if I put in the fridge straight after bottling - but there was not the slightest hint of carbonation.
When the brew is in the making I can clearly see that it is bubbling - big air pockets form under the scoby, tiny bubbles keep rocketing from the bottom of the jar, everything looks fine. But once in the bottle, everything stops.
I am under the impression that the yeast might not behave as they should. The first 10 odd batches I made after I got the scoby were great - a thick layer of foam formed already in the jar, and even if I refrigerated right after bottling I'd got some nice fizz in the morning. Now there's nothing. Removing the old layers from the scoy didn't change much, neither did playing with tea strength.
Therefore I'd say I should try following that piece of advice Shimmerlow gave me - that is using commercial kombucha as a starter for one of my next batch. Perhaps the yeast in my culture are not too strong or somehow started to die out?
As usual, any thoughts more than welcome!
Cheers!