Kefir Grains Propagation Calculator
Enter the grain weight you have now, the weight you want and how fast your grains double, to plan the feedings - or the splits - between here and there.
Results
- Whole doublings (splits)
- 1
- Milk per feeding
- 0.2 L
Share or compost surplus grains - never rinse them with hot water or let them dry out on a towel. Rinse only in cool filtered water if at all, and always feed them fresh milk.
How the growth math works
Grain mass grows exponentially: it doubles every doubling time, so days = doubling time x log2(target / current). The whole doublings along the way are the natural points to split, share or rest the grains. Milk per feeding assumes about 10 ml of fresh milk per gram of grains at each refresh - a 1:10 feeding ratio by weight.
Feeding the grains you already have? The milk kefir grain ratio calculator keeps the grains-to-milk balance right, and the water kefir ratio calculator plans the sugary side of the hobby.
Frequently asked questions
Why are my kefir grains not growing?
Growth stalls with overcrowding (too little milk per grain), all-ultra-pasteurized milk, very cold rooms or aggressive rinsing. Give them a 1:10 or richer milk ratio, keep them around 20-24 C, and avoid washing them at all - the creamy biofilm on the grains is what grows.
Can I speed up grain propagation?
Moderately: feed a 1:10 grains-to-milk ratio, keep the ferment around 22-25 C, and refresh the milk every 24 hours without ever rinsing. Pushing much beyond that makes the kefir sour before it sets, and stressed grains multiply slower, not faster.
What do I do with surplus grains?
Share them - kefir grains are a living heirloom and fermenting communities trade them constantly. Otherwise compost them, or rest a surplus in the fridge covered with fresh milk, changing the milk every week or two while they slow down.