Cold Fermentation of Milk Kefir

Cold fermentation of milk kefir is an excellent method to maintain better control over your fermentation process. During the warm summer months, it can be particularly challenging to ferment milk kefir successfully, as the grains often ferment the milk too quickly. This rapid fermentation can cause the kefir to separate much faster than usual, resulting in a watery, overly sour kefir. We receive many inquiries during the summer about how to address this issue, and our recommended solution is the cold fermentation of milk kefir.

If you’ve ever tasted mass-produced kefir, you may notice that it often has a much milder flavor compared to homemade kefir. This difference is primarily because, on a larger commercial scale, kefir is always cold fermented. Cold fermentation allows for greater control over the process, extends the kefir’s shelf life, and results in a creamier, milder kefir that appeals more to the general palate.

Before you begin, here are a few important points to consider:

1. Activating New Grains: If you’ve just received your kefir grains from us, it’s essential to activate them at room temperature and allow for at least 2 weeks of regular fermentation before attempting cold fermentation. This ensures the grains are fully active and have recovered from shipping. Otherwise, the grains may produce poor-quality kefir when using the cold fermentation method.
2. Fridge Temperature: The ideal temperature for your fridge should be set at 5°C (41°F). Temperatures colder than this will slow down the fermentation process or potentially halt it altogether. Many people keep their fridges cooler than 5°C, so this is an adjustment you’ll need to make to ensure the method works effectively.
3. Growth of Kefir Grains: Keep in mind that kefir grains will grow much more slowly using this method, and occasionally, they may even go into hibernation. If you don’t see any changes in the milk after 7 days, revive the grains by leaving them at room temperature for 24-48 hours.

Cold Fermentation of Milk Kefir Method

The ideal ratio is 1 tablespoon (15g) of milk kefir grains per 250ml of milk. However, this ratio isn’t set in stone. Generally, using more grains with less milk will reduce the overall fermentation time, but for the best consistency and taste, we find that this ratio works best.

Cold fermenting milk kefir can take anywhere from 2 to 7 days, depending on the fridge temperature and the grains-to-milk ratio. Stir the mixture well each day and check for thickening, aiming for a consistency similar to that of a drinking yogurt.

Milk kefir can still separate in the fridge, but this process occurs much more slowly and is generally easier to manage. If your kefir separates too quickly, try increasing the amount of milk or reducing the number of grains.

During the warmer summer months, this method provides you with greater control over your kefir production. We highly recommend giving it a try! Cold fermentation of milk kefir is a simple and effective way to prevent over-fermentation and to mellow out the taste of your kefir.