An Advanced Guide to the Defaults Editor
Choose the default value for the Engine Room Volume in litres, when set to 10.0 the volume section will read: 
(Default; 10)
The Percentage of the Volume that the Boil Volume section will be set to. I.e. if set to 110% when the volume is 10 Litres, the boil volume will be 11 Litres. On changing your volume the boil volume will automatically update accordingly. (Default; 110)
The amount of extract you get out of the malt as compared to a theoretical possible amount. (Default; 75)
The Liquor to Grist Ratio is simply the ratio of litres of liquor to kilos of grist. So when at the default of 2.5, with 1Kg of Malt you will get a theoretical 2.5L of Liquor (Default; 2.5)
The default value to set the attenuation of yeast to. (Default; medium, 66)
Whether or not to prompt the user if they wish to save their recipe when closing Wheeler's Wort Works. (Default; True)
The Default Boil Time of the Brew (Default; 90)
Resets the values in the Defaults Editor to those found on the Drive.
Saves the values to Temporary Memory, the changed values will be lost on next launch You can read more about this here
Saves the values to your drive, they will be opened on next launch