The Hydrometer measures the density of the homebrew. As your homebrew ferments & the yeast consumes the fermentable sugars the S.G. (Specific Gravity) will drop. It is important to ascertain that the reading has dropped as far as it will go before you bottle. If unfermented sugars still remain when you bottle you can end up with over carbonated beer or even exploding bottles. It goes without saying…this is an important tool & should be used religiously.

Draw off ¼ to ½ cup of liquid through the tap & discard. (This will clear the sediment out of tap)
Fill the test jar with liquid from tap & over the sink drop in the hydrometer.
The Specific Gravity (S.G.) will be the mark showing exactly on the surface of the liquid.
Discard the liquid…do not return it to the fermenter.
At the start the average brew will read approx. 1035 – 1040 S.G.
Bottling should take place when the reading is approx. 1006 – 1010 S.G. Again this reading is dependant on the ingredients used & ensuring the brew has finished is the most important step.