Pour a 250ml sample of your filtered sake into a graduated cylinder and take a gravity reading. After taking and recording your reading pour amount into 250ml beaker and place on heat source. Run a slow boil on the Sake because it acts differently than boiling normal water, large bubbles may appear out of nowhere, (and without warning) spilling over the sides ruining your sample measurement. Please keep a constant eye on your sample as it boils. Once you are down to exactly half of what you started, take it off of the heat and wait until it has reached room temperature, then add distilled water to raise your sample back up to original level. Pour the sample back into your graduated cylinder and take another gravity reading. Don't forget to record that as well. Input both numbers into the boxes below to get your exact ABV%.