I have not seen many good free apps for brewing but this one is useful.
It's called Convert Units. Great for converting all of those weird measuring problems you think you would never ask, How many teaspoons Ina gallon. Pints In a liter and so forth.
Grinders Island Brewery - Pipeline
Bottled! Award winning East India Porter, Oatmeal Stout, Milk Stout, Saison fermenting at a nice controlled 85 degrees (up from 70) as it should be - weird isn't it.