Lylo wrote:Or you can rattle PP's chain and just use a refractometer!!
Another thing to remember is that 'Gravity into Boil (GIB)' should always be coupled with a 'Volume into Boil (VIB)' measurement as what we really want to get from these two numbers is a pre-check on our kettle efficiency. VIB and GIB are hard numbers to measure so we can't give them too much weight. All they can do is act as a pre-check, our first kettle efficiency reading.
Anyone who has tried to take a Volume into Boil measurement knows it is hard to measure. You can turn off the flame but there is still swelling, rumbling etc carrying on at that stage.
Gravity into Boil measurements also have similar problems. For example, if you took it at mash temperature and had a crappy burner, there might be a lot of evaporation occurring between mashing out and reaching boiling point so your reading might be lower than if you took it when the boil started. Then again, if you take it at the start of boil and are using a hydrometer, you'll need to cover the sample to prevent evaporation whilst it cools.
Don't be too pedantic on this one. It is just a pre-check.
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