FERMENTATION: 2 Glass Mason Jars with wax paper

Kefir Grains create a very acidic environment, this is the sourness of Kefir. The PH of Kefir is on the order of 4.0, which means it will eat through metal over a period of time, like tomato sauce eating through aluminium foil. It is therfore important to grow Kefir Grains in glass, not metal. Since glass is inexpensive and easy to obtain, we will not discuss the use of plastic (leaching), use glass.

When it comes to lids, we do have to discuss materials. Some mason jars have glass lids with a rubber seal, some have metal lids with a rubberized lip. The easiet way yo make this a non issue regarding metal and plastics/rubber, is to simply place a sheet of wax paper over the jar and under the lid. The wax paper will keep the Kefir from contacting the lid, this allows the use of any lid without any concerns.

Use a jar that is relatively wide compared to its height, this will distribute the grains over a larger area thus providing better exchange of the fresh milk and Kefir Grains.

During the fermentation process you may choose to ferment in a tightly sealed container to carbonate the Kefir (which is what I do) or loosely sealed to keep oxygen from entering and little carbonation.

The jar most never be filled more than 1/2 to 2/3 full. Kefir Grains release large amounts of carbon dioxide which can cause and overfilled container to explode. Becuase of this disolved gas, Kefir will expand like shaken soda when you open its container. Be sure to your jar is large enough.

Fermenting Kefir Grains results in sometimes difficult to clean film inside of jars. For this reason large mouth Mason Jars are best so that you can get your hands inside the jars to clean them. Mason Jars, and wire bale jars, allow you to tightly or loosely seal the container.

You will want to have at least 3 jars; a fermentation jar, a jar to use to filter the grains into, and a jar to store the previous days Kefir. I also recomend a jar to save Kefir Grains in your refridgerator, and a spare in case a jar is broken. This totals 5 jars.

Purchase at least quart size wide mouth jars, which are available everywhere. Remember only about half the jar is usable when fermenting to allow a space for the CO2. Half gallon jars seem more difficult to obtain in local stores and I have found gallon jars (which is what I use) only avialable online. Here are links to jars online, the gallon jars are the ones I use:

On average, I break a jar about once every 2 to 3 months, usually moving too fast while cleaning them. But sometime banging them against each other. So be sure to have one or two spares on hand.