* Please note that this blog remains up as a resource. However, this blog is currently on hiatus until further notice. For more information, please read this blog post. Thank you and happy kombucha brewing, drinking, and SCOBY trading! Lots of love. ~Annabelle *

Monday, February 1, 2010

Broken Glass

As I was washing the dishes one day, I heard a slight crack. I looked around the kitchen but didn't notice anything...but soon the smell of kombucha filled the room. Uh-oh.

It turns out, a bottle of my kombucha had exploded- as a kind reminder not to leave your kombucha bottles out for too long for a second fermentation.

I have been fortunate to have never had a bottle of kombucha explode on me before this day, and after brewing kombucha for over a year, I guess it was about time.

Luckily, the explosion was a lot less dramatic than it could have been. When I first began bottling kombucha, I had been nervous about shards of glass ending up on on my wall.

Tips to avoid kombucha bottle explosions:

-As mentioned in my previous post, Kombucha + Fizz:
  • Beer bottles with their narrow necks and tight caps are ideal for creating fizz, and the longer you leave your bottles out for a secondary fermentation, the more fizz will build up. HOWEVER, if you leave your bottles out for too long, and especially with such tight seals, you run the risk of them exploding. Some people recommend 1-2 days for a secondary fermentation, others 3-4 days, and some recommend even longer. It all depends on various factors, such as temperature (higher temperatures = faster fermentation).
  • My advice: If you're fermenting a batch, try a bottle after 1 or 2 days (more or less days depending on previous experiences, etc.). Then decide whether your other bottles are ready to refrigerate, or if they could use some more time fermenting.
  • If you can hear your kombucha bottles at room temperature fizzing, refrigerate it!!
**Please note that this graph is not to scale whatsoever, and was merely created in order to illustrate a concept.**

***The longer you leave your kombucha bottles out for a second fermentation, the more fizzy your kombucha, but the more risk you will have of your bottles exploding. Experimentation and practice are key!***

-Read this discussion thread on bottling technique from some fellow kombucha fermenters.
  • According to this thread, flip-top beer bottles can be a good option, because the rubber seal releases some of the pressure that may cause your bottle to explode.

Adding to my list of broken kombucha bottles includes one instance when my refrigerator somehow got to freezing temperatures, causing the kombucha to freeze and expand (when water freezes into ice, the volume expands as the molecules form a crystal lattice), causing another kombucha bottle to break.

At the time I decided to take an artistic approach to the situation, resulting in this photo:

Kombuch-sicle, anyone?

Home-brewing (and in fact, brewing in general) is never perfect. Accidents happen, but they are all part of learning how to brew and how to perfect your technique, and make your home-brewed kombucha that much more worthwhile. What interesting kombucha experiences have you had?


e said...

Happened to me for the first time last night. I thought someone was breaking into the house. Spending today trying to hunt down all the tiny pieces of glass on my floor.

Anonymous said...

I have a bottle in the fridge and noticed the bottom of the glass jar, my little guys seem "sludgey" looking. I have never seen ths before and nope I have not opened it because I am a big chicken. Has anyone seen this?

Annabelle Ho said...

@e Sorry that you had to experience some bottles exploding! I hope it hasn't happened again.

@Anonymous The "sludgey" parts may be dead yeast cells, which are common. Usually I will just strain these parts out. I would also recommend looking through these photos that Happy Herbalist has posted of kombucha mushrooms and ferments, to see if what you have looks similar: http://www.happyherbalist.com/gallery.htm.

Anonymous said...

Hi! I am new to brewing kombucha and have just made my first batch and am very nervous about this second fermentation part-- I don't want to have glass explode!! Any tips you can give to avoid this? Also, what is the best amount of time for the first fermentation? And how will I know how to separate the scoby from the mother? Thanks!!!

-Anxious beginner but lover of kombucha

Annabelle Ho said...


I'm glad that you are beginning to brew kombucha! To avoid this, avoiding extremely high temperatures is helpful (especially if it's over 90 F). "Ideal" temperatures are around 75-85 F. Leaving some headspace at the top of the bottle helps. In addition, if you have a batch of bottles fermenting, open a bottle every few days, to see how the fermentation is coming along. Once it tastes like it's ready, put the bottles in the fridge.

The amount of time for the first fermentation varies. It can be from 7 days-a few weeks. Looking at this chart is a good visualization of what's happening: http://www.kombuchafuel.com/2009/09/factors-affecting-your-brew.html. Ways to tell if your brew is done is if a new SCOBY forms, the tea looks cloudy, and you begin to smell something similar to apple cider vinegar. The best way to tell if kombucha is done is by taste, since people have individual preferences.

Often you can peel off the new SCOBY from the mother. Sometimes they are inseparable, and that's ok.

Good luck and have fun!

Anonymous said...

Im just starting the learning curve. love it.

help I did a second fermentation,for 36 hrs then put in the refrigerator but I can NOT open the used KT bottle. I had 4 different guys try. rock climbing strong hands. Any tricks or is this pre explode mode? it is in the refrigerator now