Perhaps you’ve seen this happen, and it even happens to me from time to time: My kefir will get really sour. This can happens for several reasons.
During your first ferment you let your kefir ferment too long on your counter, or your house might be warmer than usual.
Kefir will also ferment quicker if your grains have grown and multiplied, and you didn’t increase the milk or remove some of the grains.
You leave your finished kefir in the fridge for a long time and don’t drink it. Remember that kefir still ferments a little in your fridge. The longer it is in there, the more the bacteria will eat the sugars out of the milk and make it sour.
Here are some of the things you can do to make this better:
Second fermenting your kefir will always help with kefir that is sour. It really makes it taste so much better. Whenever you add something to kefir to second ferment, be it fruit or the peel of fruit, you give the good bacteria something else to eat instead. The bacteria turns it into probiotics and they love it. It is essentially like feeding the bacteria again, which in turn makes your kefir less sour.
Instead of making your regular recipe with a large amount of kefir, split it up. For instance, instead of using a cup of kefir for a recipe, only use a 1/2 of a cup and then use regular milk, coconut milk, or my favorite -kefir cottage cheese, and blend it together. It’s a lot less sour this way.
You can also add some more milk to your super sour kefir and let it ferment again on the counter for 4 to 6 hours. This will help it to lessen the sharp twang. You don’t need to add kefir grains. It will work without them because the kefir is so strong.
Make your kefir into a fruit smoothie! (see recipe below) The fruit I add most often to help with the sourness is a banana. I’m not sure why but bananas seem to help a lot in cutting down on the sourness of kefir.
One more ingredient that helps significantly is vanilla or lemon extract. It tends to mellow out the flavors. You can also add my own homemade rum vanilla to my smoothies, ice cream, and desserts in general. I usually add a 1/2 tbsp.