# To make plain crude kilju, the must weight must be zero: A fermentation lock should indicate less than a bubble per minute. Then the sugar reserve is measured with a must weight refractometer/hygrometer. If there's sugar left, then more yeast should be added to consume it, and this measurement process should be repeated. A solution with sugar is not fermented water, but fermented syrup.
# Clarification: The solution is clarified, typically with a fining agent like bentonite.
# Alcohol by volume: Only when the must weight is zero, and when the solution has been clarified, an alcoholic hydrometer, or an ethanol-type refractometer, will display accurate alcohol volume. A leftover sugar reserve will give false values.