Sick Scoby

I’ve got a sick SCOBY on my hands. Things had been going well with the Kombucha brewing (see part I and part II of the experiment). I generally start off each batch and then forget about it until I get a reminder on my phone telling me that it should be nearly ready. Unfortunately, when I checked on the last batch, I found a sick SCOBY.

Scoby with grey edgeThis is definitely not mould but the SCOBY has a grey colour along the edges that doesn’t look good. There has always been brown stringy substances floating in the container and attached to the SCOBY. These are not a problem – it is just a by-product of the yeast culture. This greyness is different though and seems to be changing the colour of the SCOBY itself. The Kombucha from this batch is very cloudy and doesn’t taste good so I’m throwing it out.

From reading, it seems that the grey colour could be a sign that the SCOBY is worn out but apparently SCOBY exhaustion doesn’t happen very often and wearing out a SCOBY should take a long time. I suspect emotional contagion might be at play!

Sick scoby - side viewAnother (more realistic) possibility is that something contaminated my brew. I notice that the covering cloth is now discoloured so I think that maybe the SCOBY tried to climb out of the jar (yes it happens when there is too much CO2). If this was the case then the SCOBY would have been touching the cloth for some time and this might have caused the problem.

In any case, this is all part of the fun of home-brewing. There was a second SCOBY that had detached from the others and was sitting at the bottom of the jar. It doesn’t have any signs of greyness so I’ve added it to a new jar of tea. I didn’t think it was safe to use the Kombucha from the grey batch but had some left over from a previous batch so I used it instead. Now I just have to wait. Fingers crossed for no more exhausted SCOBYs.

If you are running into any Kombucha problems, I recommend these websites for troubleshooting:


The Kombucha experiment – Part II

I’m tying up the loose ends of 2013 by writing Part II of the Kombucha experiment (see Part I here).

Since I the experiment started, I received a very kind offer of a SCOBY from the good people at l’Heure Bleue in Belgium. Unfortunately, security at Brussels Airport had other ideas about international trafficking of SCOBYs in containers that are larger than 100ml and sadly is was consigned to the bin.

In the mean-time, my own SCOBY seems to be doing pretty well. Three weeks after it started to grow, the SCOBY was thin looking but there was no mould and it had patches that were thick and white so I deemed it safe and went ahead a brewed my first batch of Kombucha.


I don’t know how important the rules of SCOBY-handling are but one of the most common rules is no metal touching the SCOBY so no spoons, jewellery, metal containers etc. Before handling the SCOBY hands should be clean but not with antibacterial soup. Cider vinegar seems to be the best way to clean your hands before handling.

Once you have successfully grown the SCOBY, here’s what is needed to prepare the first brew of Kombucha:

  • 200-300ml of the liquid that the SCOBY formed in
  • 2 litres of tea
  • 175g of sugar
  • A large, clean glass container
  • A tea towel and elastic band

Brew the tea by steeping the tea leaves in 2 litres of boiling water. Add the sugar and allow it to brew for at least 30 minutes. At this stage it is ok to use metal to stir because the SCOBY has not been introduced. Strain the leaves and pour into the clean glass container then leave to cool. It took around four hours for mine to cool to room temperature. Any hotter than this will harm the SCOBY but too cold is not good either (temperamental, these SCOBYs!!).

SCOBY in new homeOnce it is cool enough, slide the SCOBY into the large glass container and add approx. 300ml of the liquid that it grew in. The rest of the liquid that the SCOBY formed in can be discarded. Apparently it is safe to drink but is just very weak kombucha and not very tasty.

When the SCOBY is added it might float or sink or it might try some acrobatics with a half-floating manoeuvre, like mine did. It doesn’t really matter. Cover the glass container with a tea towel and elastic band and put it in a warm dry place.


Kombucha takes about 2 weeks to brew but the brew time can be adjusted to personal taste. It becomes less sweet with time but factors like temperature and surface area will also affect the speed of the process. Ideally, brewing should take place between 22 and 29°C. Mine is at 18°C so brewing time will definitely be longer.

Rehoming SCOBY

Once the first batch is ready you can bottle the kombucha and transfer the SCOBY (with 200ml of the brewed kombucha) to a new preparation of sweetened tea and the process starts all over again.

Kombucha naturally has very gentle carbonation that gives a tingling sensation but to get more fizz, let it sit in an airtight bottles at room temperature for a day or two. I’ve read about adding blueberries or ginger to boost carbonation but haven’t tried this yet.

Each time you brew a batch of Kombucha, a new SCOBY will grow adjacent to the original SCOBY. You can leave them together or separate to share with friends or start making jewellery!

The Kombucha experiment – Part I

As usual, I’m a couple of years behind the trend. Kombucha is a drink that was extremely fashionable a few years ago but it still has a solid following. It is a tea drink that is made by fermenting sweetened black tea with a culture of yeasts and bacteria. It is also known as Tea Kvass (Russia), Hongchajun (China) and Kocha Kinoko (Japan). Confusingly, in Japan, Kombucha refers to seaweed that is powdered to produce kelp-tea. The two “kombucha” are very different.

Many websites talk about  probiotics and the detoxification and immune boosting properties of Kombucha (see notes on health at the end of article) but it also happens to be a very tasty drink that is naturally carbonated.

DBKB KombuchaWe are lucky in Dublin to have a local, organic, non-flavoured, Kombucha “brewery”. This is a very convenient option especially if you are short on time but I’ve never been one to take the easy route so I decided to experiment and try brewing my own.

A SCOBY (Symbiotic Culture of Bacteria and Yeast) is needed to prepare Kombucha.  The SCOBY is sometimes called a mushroom but it’s just a colony of bacteria and yeast – no fungus. I’ve looked at lots of websites with instructions on how to brew Kombucha and almost all of them say that you start with a SCOBY. I was having some trouble locating a SCOBY but then I came across an article that said you could grow your own SCOBY so I decided to try that. I don’t know how this is going to turn out- we have to wait for two weeks to see if it works or not but here were my steps for preparation.

Kombucha IngredientsI brewed 500ml of tea. I would have preferred to use an organic black tea but I had none so I used a regular Panyong Golden Needle. I left it to steep for 10 mins and then removed the tea leaves, added 1 tsp. of sugar and allowed it to cool for 30 mins. I have since read that heat can be very destructive to the whole scoby-growing process and at 30 minutes it was still warm so this could be a problem. Leaving it for an hour would be a safer bet.

After 30 minutes I added 330ml of raw Kombucha (I used DBKB).   After adding the Kombucha I covered the bowl with a tea towel and put it in a warm dry place. I used a glass bowl because apparantly the acidity of the tea can cause it to absorb harmful elements from containers that are painted, ceramic etc (there has been two reported incidences of lead poisoning where Kombucha tea was brewed in a ceramic pot).

And now I have to wait for 2-3 weeks….

Health Note: Since the early 19th century, Kombucha tea has been promoted as an immunity-boosting tea that can strengthen the body and prevent many ailments. There is no solid scientific evidence to support the health claims of Kombucha tea.  In addition, there are potential health risks from Kombucha (source) but these equally, are not backed by solid scientific research. Because of the potential health risks, people with an immune deficiency or any other medical condition should seek medical advice before drinking the tea. Women who are pregnant or breast-feeding should not use this tea.