This procedure is taken from dom's site, which you will find by typing in "kefir" on google. It's the number one site.
The method explained below, will reduce most if not all the lactose from the kefir, making it most favourable for Lactose Intolerant individuals, or for individuals who need to watch their
Sugar or carbohydrate intake [e.g., Diabetics or Low Carb Dieters]. This method is the no-fridge method. This is performed by placing freshly strained kefir in a sealed container and storing [ripening] at room temperature. This system is similar to how kefir was stored by the original kefir-makers of Caucasus, due to no refrigerators at the time [hence their need for kefir]! Note that the method will produce a kefir with lots of FIZZ! So please practice with care and with common sense [use a blend of all your sensory perceptions], blended with common knowledge
[Excessive pressure = the possibility for an explosion if using an airtight container that is not designed to take high pressure].
Freshly strained kefir may be placed in a glass [or plastic] bottle and stored at room temperature for up to 1 week.
METHOD
Pour freshly strained 12 to 24 hour brewed kefir into a glass [or plastic] bottle, not filling the bottle more than 3/4 full
Place a tight fitting lid on the bottle
*Give the bottle a good shake once or twice daily [to prevent spillage, make sure the lid is tightly fitted before shaking]. Release any CO2 gas build-up by opening the lid, then tighten the lid once again
One may pour amounts of kefir from the bottle daily, until all the kefir is consumed.
Alternatively, after removing a portion of kefir, replenish the bottle with freshly strained kefir; repeating the process daily.
*The kefir must be shaken 1 - 2 times daily. The reason for this is to prevent Yeasts and Acetobacter colonies from forming. If not agitated, these colonies may be seen forming on the surface of the kefir, seen as a flaky light-brown wavy film. This phenomenon is similar to The Flowers of Wine [Mycodermia] in wine-making. In this case, I refer to this film as Flowers of Kefir [please see this picture]. Although the initial development of such colonies are not harmful, if left unchecked mold may begin propagation; agitation prevents this from forming possibly due to increased oxygen, which I find is most favourable.
Due to secondary fermentation, the processes explained above may produce a slightly sourer tasting kefir, with a considerable increase in effervescence. Although, this process will produce a kefir with less sourness in comparison to a kefir stored in the refrigerator, stored for the same period of time. Some of the B group vitamins, particularly Folic acid [Folacin], will increase as the kefir is left to ripen for a few days. Within this time, *Folic acid may increase by 116 % in comparison to the original fresh milk or freshly stained kefir! Ripened kefir is favourable taken during pregnancy.