Read many of the "Ginger bug" threads here, and otherwise searched for use of Refractometer (a simple and cheap device that can measure sugar levels), but found very little info.
My question is why not just measure sugar levels, and see. In my (short) experience, G/B seem to do best with 5% sugar, as soon as it goes up to 10-15-20%, then it dies.. to "fix" this, just pour liquid and replace with water, measure, until you get close to 5%, add a bit of new ginger, and u should be fine, it will bubble shortly after.
Any thoughts on refractometers? I got a cheap one from ebay.
Stormy.