Originally Posted by Cistercian
What is the most dry ale yeast (lowest FG) out there, both in liquid and in dry?
That question really depends on the sugar content and type of the wort you're fermenting. Any beer yeast in 100% sucrose and fructose will ferment to totally dry. That's why wine yeast get below 1.000 because the sugars are easily fermentable.
Maltose isn't so easily fermentable. It contains a few different complex/long chain sugars that the yeast can't break up. That's why enzymatic action in Partial Mash and All Grain brewing makes such a huge difference in wort composition and fermentability. Too many long chain sugars and it doesn't really matter what yeast you use, it just won't ferment out.
That being said, some strains do better on more dexterous wort that others. I'd begin by looking at the yeast manufacturers web sites and checking the Apparent Attenuation numbers they publish. That number references what each yeast strain does against a lab wort that is exactly the same for each yeast tested. Higher percentages would mean they would ferment out dryer than others, but you also have to watch and make sure that the yeast works for the style your brewing.