from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The state or condition of being fermentable.
from the GNU version of the Collaborative International Dictionary of English
- n. Capability of fermentation.
from The Century Dictionary and Cyclopedia
- n. Capability of being fermented.
Sorry, no etymologies found.
So, the beers made from the first runnings were of the highest quality and highest fermentability.
These flavors and aromas are derived from a slight high-temperature roasting (like in an oven) once the malt has been dried; this roasting process reduces (though does not usually eliminate) the fermentability of the malt, but adds color, flavor and aroma.
(Pouring the wort into the boiling water will stop any enzymatic activity and "fix" the fermentability of that wort.