Milk Kefir Second Ferment (Flavor & Sodas!)

Wondering how you can add flavor to milk kefir during the second ferment? Here’s how to turn kefir into a yogurt-like drink or a soda pop!

What is a second ferment?

Primary and secondary ferments occur for most fermented beverages. The primary ferment is when you first set up the fermentation. Then after a few days (kombucha) or weeks (beer), the beverage is moved to a clean container for a second round of fermentation.

For example, the primary ferment for milk kefir is when you put your grains in milk and leave it on the counter to culture. When you remove the grains and pop the milk kefir in the fridge, you’ve essentially halted the primary fermentation.

A second fermentation occurs when you allow the kefir to continue to ferment after the grains are removed.

Here are the main reasons to do a second ferment of milk kefir:

1. To get the milk kefir to separate, so you can make milk kefir cheese and whey.
2. Add flavor to the milk kefir (see the blueberry kefir, above).
3. Bottle it for a sparkling milk kefir soda (see below).

Adding flavor to milk kefir

Once you’ve removed the grain, feel free to add whatever flavors you want to your milk kefir. Popular flavor additions include:

• fresh fruit
• vanilla extract
• citrus zest
• maple syrup
• jam

Here are a few notes about flavoring your kefir:

1. I recommend adding flavors either right before serving or 24 hours before serving for the freshest mix.
2. Flavors with sugars in them (fruit, maple syrup, jam) will feed the yeast in the kefir, making it a bit more sparkly.
3. Acidic flavors may cause your kefir to curd and separate.

Milk Kefir Soda

On a sunny Saturday afternoon, a sparkling and flavor-packed soda is just what you’re looking for. There are a lot of types of fermented and probiotic sodas. If you happen to make milk kefir, then it’s really easy to make milk kefir soda!

The recipe for milk kefir soda is at the bottom of the post, but I wanted to share more details for anyone new to brewing soda.

Sugar for milk kefir soda

Milk kefir is a really vigorous culture. It will ferment with pretty much any type of sugar.

• Milk kefir will sparkle and ferment without extra sugar. However, if you’re planning to flavor with brewed tea I recommend including a bit of sugar to feed the carbonation. (See the flavors below for details).
• Unlike some other types of fermented soda, it will happily ferment 100% fruit juice, white sugar, or maple syrup.
• Steer clear of xylitol, artificial sweeteners, and zero-calorie sweeteners (stevia and monk fruit). These won’t help the kefir carbonate.
• If you’re using honey, make sure it’s pasteurized so the culture in the honey doesn’t compete with the kefir culture.

Milk kefir soda flavors

When deciding how to flavor your milk kefir soda, choose flavors that will complement the milk. Personally, I prefer to stick with cream soda flavors.

1. Vanilla bean: Vanilla is a natural flavor for milk kefir. Feel free to add the inside of 1/2 a vanilla bean, or 1 tsp of vanilla extract to any of the flavors.
2. Fruit Juice: 1 cup of milk kefir can be mixed with up to 3 cups of juice. Berry juices and mango are delicious. I don’t recommend citrus or pineapple which will cause the yeasts in the kefir to become stringy and less appetizing.
3. Whole fruit: It’s fine to flavor kefir with fresh or dried fruit. I like adding raisins and vanilla to tea for a classic cream soda flavor. (See photo below).
4. Zest: Orange zest is the best way to get a citrus flavor infusion. I make an orange creamsicle flavor by using a mix of orange zest and vanilla with fruit juice.
5. Tea And Coffee: I love tea-flavored sodas. Just like juice, 1 cup of milk kefir can be mixed with up to 3 cups of brewed tea or coffee. The only difference is that tea doesn’t have any sugar to help carbonate the soda. So add at least 2 tsp of sugar per cup of tea to feed the ferment.

Milk kefir or whey soda?

Soda can be brewed with straight milk kefir or the whey of separated kefir. It really depends on what you’re looking for.

• Whey will ferment into a clear soda. So it’s better if you want something that is more like traditional soda pop.
• Straight milk kefir mixed will separate as it ferments. You can either shake it up before serving or strain out the dairy. (See below for a soda brewed with tea and milk kefir).
• I usually use whey for my sodas since the resulting beverage doesn’t have milk proteins. I also love making kefir cheese, and the two go hand-in-hand. The mango soda in the photo above was brewed with whey.