MY MILK KEFIR-GRAINS ARE GROWING FLAT, OR LIKE A DEFLATED RUBBER BALLON. ARE THEY DAMAGED?
The shape of grains to come!
No, your grains are not damaged, and you do NOT have special, rare grains, as some folks on the net are suggesting. All milk kefir-grains shall, and do go through phases of variable growth in regards to shape, size and texture or make up of the grain. This is because the organisms adapt to culture-conditions, the result of which is a variable grain shape, size, and texture of each grain. There's lots happening among the micro-community of organisms. How these are forced to build their abode [the grain], is quite fascinating to observe under so many culture-conditions.
In the case with flat sheathed grains this is usually a result of self-enclosed grains being popped open by physical means, such as excessive squeezing or pushing on the grain, or tearing or cutting the grain into smaller pieces. The opening of such grains lets in milk, and over time those grains will be forced to grow as large, flat sheaths, instead of self-enclosed bodies. However, if future culture conditions allows little interference regarding physical trauma, then those flat grains will eventually grow to the natural shape and form, which are self-enclosed bodies or grains. The cycle from flat sheaths to self-enclosed bodies may take up to 9 months to occur. Please note that flat sheathed grains are not damaged grains by no means. In fact, I suggest to tear apart larger grains, for smaller flat grains usually produce a creamier kefir, due to kefiran leaching into the surrounding milk from both sides of the matrix [the once interior and exterior surface]---i.e., while the grains remain as flat sheaths. But again, within a few months, those flat sheaths will grow into self-enclosed bodies.
Grains that appear as smooth, deflated rubber balloons is also a phase of growth, and is no indication of damage or inferior grain-type. Those grains will evolve into the more common type in shape and texture. Again, this may take some months to occur. Colder culture-conditions has the effect of creating grains with a rougher surface, and the makeup of such grains is more durable, rubbery in texture as apposed to soft and slimy. This is because of greater protein content and less kefiran content, due to less kefiran production under colder conditions.