Weighing Small Quantities
Doesn't it drive you crazy when you scale a formula down to a size you can make at home and you end up needing .011 oz. of yeast? You can do this if you have a scale that will measure in grains or fractions of grams. A grain is a unit of weight that is 1/7000 of a pound or about 1/438 of an oz. When I'm making poolish for my home-size batch of croissants and find that I need .005 oz. of yeast it's an easy matter to weigh out 2 grains of yeast. It's not that I need extreme precision (if I did then I'd weigh out 2.2 grains of yeast) but when I see what a tiny amount of yeast 2 grains is, I know that if I had to estimate it by volume I could easily use two or three times too much.
Fortunately, you don't have to buy an expensive lab-quality scale to weigh things in grains, or tenths of grains. Reloading scales are relatively inexpensive and easy to find. There are both digital ones and beam balances. The benefit of having a digital is that they have a tare button so you can avoid doing arithmetic. Any sporting goods store that sells reloading equipment will probably sell these for an affordable price. Midway USA has one for as low as $35: http://www.midwayusa.com/browse/BrowseCategories.aspx?tabId=1&categoryId=9211&categoryString=9315***731*** and Cabela's has some at http://www.cabelas.com/cabelas/en/templates/index/index-display.jsp?cmCat=MainCatcat602007-cat20728&id=cat20853.
I have these from my days of competitive rifle shooting. I only use the digital scale now and almost always use it for yeast, salt, malt powder, and anything else I need tiny amounts of. The digital reads out in either tenths of a grain or hundredths of a gram. It can be precisely calibrated with the weights and although that is a good idea when weighing out gunpowder, I don't do it all that often for baking.