How Long Do Ayran and Kefir Keep in the Refrigerator?

Once opened, ayran (a yogurt drink) should be tightly sealed and consumed within 3–4 days when refrigerated; homemade ayran lasts less time than store-bought and is generally recommended to be finished within 2 days. Kefir tends to become sour a little more readily than ayran by nature; after opening, it can be stored in the refrigerator for about 5–7 days, but it becomes more sour as the days pass, so consuming it sooner keeps its flavor more balanced. Why does souring speed up? Because both drinks are fermented dairy products, the microorganisms in them continue to work slowly even in the refrigerator; as a result, there is a noticeable difference between the taste on the first day and on the fourth or fifth day. This process moves much more slowly in a cool refrigerator than at room temperature. Closing the bottle quickly each time it is opened reduces the surface exposed to air and delays souring somewhat; rather than keeping a large bottle open for a long time, it is better to pour only what you need into a smaller container. Can they be frozen? When ayran is frozen and thawed, its texture is disrupted, the milk and water separate, and it becomes unpleasant to drink; freezing is therefore not recommended. Kefir also loses its consistency and becomes more watery when frozen and thawed. Instead of freezing leftover ayran or kefir, use it in a yogurt-based soup or baked goods so it can be consumed without waste. Is there a difference for homemade ayran and kefir? Homemade ayran keeps for less time than store-bought pasteurized ayran because the microorganisms in it are still active; it therefore makes more sense to prepare only enough homemade ayran to consume within a few days rather than making a large quantity. Kefir fermented at home is a live culture continuously produced with its own starter (kefir grains); unused kefir grains can be kept in a separate container in the refrigerator with a little milk, ready for the next batch. A slight layer of foam that builds up in the bottle is a normal sign that fermentation is continuing in ayran and kefir; however, do not consume the drink if the foam is accompanied by a sharp, unpleasant smell. If ayran is poured without shaking, there may be some foam on top and a slightly thicker consistency at the bottom; this is natural separation of the components, and shaking before drinking is enough. If kefir sits in the refrigerator longer, a pale liquid (whey) may separate on top; this is not spoilage and can be stirred back in before drinking. Keeping a bottle of ayran or kefir on an inside refrigerator shelf rather than in the door reduces temperature fluctuations and slows souring somewhat. Homemade kefir may be slightly foamy and fizzy in the first few days; this is normal, and this activity decreases somewhat over time, making the flavor a little milder as well. Ultimately, ayran and kefir have a limited life after opening; keeping the cap tightly closed and consuming them early is the key to enjoying the best flavor of both.