Now that you’ve mastered the art of basic brewing (see part 1 here!), let’s move on to the fun part of making kombucha – flavouring and carbonating. This process is called secondary fermentation because the cultures feed off the sugar in the things you’ve added – typically fruit – and in this way continue the fermentation process.
We’ll also cover how to manage your SCOBIES, including how to store them for future use or split them to give away to another home brewer.
When it comes to flavouring kombucha, you can really get creative: it’s possible to enhance your brew with a range of fruit, herbs, spices and edible flowers. Sometimes the end result will be underwhelming, but finding out what works and what doesn’t is all part of the fun.
A good rule of thumb to start with is to keep fruit or other flavourings to about 10 per cent of the overall brew. Don’t worry about sticking exactly to a 10 per cent limit, though. You can use fruit puree or fruit juice, but I found that sticking to fresh fruit gave the best results, possibly because there is no added sugar or other preservatives.
I’ve experimented with a range of fruit and had some hits and misses. Pineapple, for example, created carbonation very quickly, so unless you want to risk an exploding bottle of kombucha don’t add too much. Canned peaches added almost no taste, but fresh peaches may work better. I had more luck with candied ginger, which was one of my favourite flavourings.
Berries, such as blueberries and strawberries, give it a refreshing sweet and sour twist. Lychees work just as well, and they reminded me of lychee martinis without the hefty price tag, and high sugar and alcohol levels. If you’re after a more soothing taste, I recommend trying mint. I’m yet to experiment with rosemary or lavender, but other brewers have reported tasty results.
You can also alter the flavour of the kombucha by straining out the yeast – the stringy bits floating around in the brewing vessel – when you transfer it to the bottle. Yeast tends to give the kombucha a beer-like mouthfeel. It’s not necessary to remove it – some people like the flavour – but I prefer to take it out.
Whatever you choose to flavour your kombucha with, you’ll add it during the bottling process.
To do this, you empty 75 per cent of the kombucha from the brewing vessel into bottles. The remaining 25 per cent you’ll need to keep to start the next batch. You need to leave some space in each bottle for secondary fermentation, which will carbonate the kombucha (that is, make it bubbly), so fill the bottles only to slightly below the start of the bottleneck.
Airtight bottles work the best because they trap the air in the neck of the bottle and thus assist the carbonation process (bottles with a flip-top lid that seals in the air are ideal). For a similar reason, it’s best to go with bottles that have narrow necks. When you’ve finished transferring the kombucha to the bottle and adding the fruit, make sure the cap is on tight and there are no leaks.
It’s generally best to use glass bottles, as glass is non-reactive. If you use plastic, the acidic environment of kombucha will leech the plastic and may release toxins. Glass is also better for retaining carbonation; plastic bottles can expand and enable the gas to leak out (that’s why beer is always sold in glass bottles or aluminium cans).
Make sure the bottles are high-quality glass as you want to prevent cracks or breakage in the event of over-carbonation. Old kombucha bottles or liquor bottles should work. Some kombucha brands use tough, food-grade plastic, so their old bottles should work but I’m yet to try them.
Once you’ve snapped the lid on, place the bottles in a warm, dry place (the place you fermented the kombucha should work well). The longer you leave them, the more carbonated the brew will be. In Singapore’s tropical climate, that means you should drink them within three days.
Any longer may risk an explosion, which can create a big mess – it’s not unheard of for kombucha to splatter on the ceiling. If the glass is of poor quality, it can also shatter easily so be careful when opening your kombucha bottle. To be safe, I usually open it in a sink.
If you want to store the bottles for longer, put them in a cool place once they are carbonated to slow down the secondary fermentation process. They also taste better chilled.
Storing or giving away your SCOBIES
If you are taking a break from brewing but want to keep your SCOBIES in good health, or you want to have a backup SCOBY in case of mould, you can store them in a SCOBY hotel.
You can make a SCOBY hotel by splitting the SCOBY and dividing the starter tea into two or more jars. You can do this by removing the SCOBY with clean hands, and then either cutting it in half with a pair of scissors or splitting it in two by pulling apart the layers.
Divide the starter tea between the jars and add sweetened tea as you would in a basic kombucha brew. You now have two vessels – the first of which is your main brewing vessel, the other your SCOBY hotel.
Fermentation will continue while the SCOBY takes up residence in the hotel. You will need to maintain the hotel by discarding about a third of the tea and refilling it with sweetened tea every month or so. This will give the cultures a continuous supply of sugar to feed on.
A SCOBY hotel can go untouched for months due to its acidic qualities, but it’s always a good idea to check up on it every few weeks, particularly given Singapore’s warm weather. Over time your SCOBY will build up several layers – enough for backups, experimenting with different types of teas or giving away to friends.
It’s not advisable to store your SCOBY in the fridge, as it may take a long time to awaken the cultures when you remove them from the cool air. It can also put your batch at greater risk of developing mould. If you have stored it in the fridge, leave it out for a day or two at room temperature to wake the cultures before brewing.
To transport your SCOBY, simply seal it in a Ziploc bag along with some starter tea, pass it on to a friend and show him or her the brewing ropes. I’ve even successfully transported mine overseas by putting the bag of SCOBY in its brewing jar and then wrapping the jar in newspaper to prevent breakage. The jar then goes into my check-in baggage.
I hope this two-part how-to enlightens you on brewing kombucha – particularly, how cheap, easy and fun it is. Good luck, and spread the kombucha kindness by giving the extra SCOBIES away to a friend who could use some healthy, live cultures!