The first thing I would say about kefir is, EVERYONE will tell you something different. Brewing kefir is just like making any other dish. There are hundreds of variations and recipes out there, each one somebody’s favorite. Everyone will swear doing this or that particular thing will make the beverage more healthful for you — and often the advice is contradictory. My point of view? Relax. Just do it. Enjoy it. Experiment and see what works for you, what you like and don't like. If it doesn't  work, chalk it down to experience and try aga

The great thing about flavouring your kefir with a second ferment is that as you have already removed the scoby (grains) you are not risking it by flavouring your Kefir this way. Never add anything to favour your kefir on the first ferment (f1) the ginger lemon and dried fruit that you add if you are following are recipe are not added top flavour they are added for minerals to help the grains.

If you do not like the kefir that you make you can throw it away and other than being a bit short of your kefir for a while until your next brew is ready, there is no harm done and your grains are fine. 

The next advantage is that you can make many different flavors with the same batch or you can make them all the same the choice is yours. I would recommend keeping a journal of your experiments so when you hit the jackpot and make a kefir that literally blows you away, you have a record of how you did it. Too many times, I have put a bit of this in and then a bit off that, left it and then tasted it a couple of days later to find that I have created a wonder juice only to find that I cannot recreate the wonder juice as I forgot to write down what I put in it and can’t remember afterwards!!

How to Second Ferment Water kefir (f2):

1. Brew your Kefir as normal
2. when your brew is ready to bottle it pour off your drink as normal
3. In the bottles you would normally bottle with, add around your flavour. We would recommend 1/3 fruit juice to the bottom of the bottle (I like organic fruit juice but that's a personal preference, avoid cloudy fruit juices as they can add stringy bits to your drink! you can also use fresh fruit if you wish, slices of lemon and ginger are a nice addition). You can also use fuit infusions (fruit tea- just make sure it has cooled before adding it) or cordials can work well (like ginger cordial) or fresh/dried herbs and spices. 
4. Top up your bottle as normal, seal them with a cap or stopper and store in your usual fermenting place.
5. Leave for at least 48 hours depending on temperature*
6. Start your next brew in the normal way (f1)
7. When your flavoured kefir is ready**, chill in the fridge (chilled Kefir tastes better), drink and enjoy. 

Notes

* The temperature that you brew at determines how long your brew takes and the same is so for a second ferment. If you are storing your fermenting bottles somewhere warm (around 22c) then they will likely be ready in around 1-3 hours. If the area is cooler it will take longer. It can take a week or longer for a second ferment depending on the temperature.

**How do I know when it’s ready... This comes down to personal preference again, but as a rule it should taste mildly sweet but mostly tart in flavor.