My cousin, Greg Lanham, and I have many similarities. We're the same age (born four days apart), we grew up in Colorado, and we went to Colorado State University at the same time and got degrees in mechanical engineering. The main difference is that I was a lousy engineer but Greg is a very good engineer. That's why I know his digital hydrometer "designed to aid the artisan brewer, winemaker and distiller in their craft" will work as advertised.
One of the key measurements obtained with a hydrometer during alcohol production is sugar concentration; this is an important measurement because, basically, sugar is the food for the yeast. By knowing the amount of sugar, the craftsman can control the alcohol content and flavor of the beverage being produced. This value is measured at different points throughout the process to ensure a repeatable, quality product every time.
Because the eDrometer is so fast and easy to use the craftsman can easily take measurements before, during and after fermentation, allowing them to consistently dial in their recipe.
Mark Frauenfelder is the founder of Boing Boing and the editor-in-chief of MAKE and Cool Tools. Twitter: @frauenfelder. His new book is Maker Dad: Lunch Box Guitars, Antigravity Jars, and 22 Other Incredibly Cool Father-Daughter DIY Projects