What's the least wasteful way to brew coffee?
What brewing method uses the least coffee for the taste? Or, which method is most efficient in terms of beans per cup? I've heard that the french press uses more ground coffee than other methods for the same strength cup of coffee. Is this true?
All other things being equal, the fineness of the grind will likely have the most impact on “efficiency”. In other words, the greater the surface area of the bean that is exposed to the hot water, the more flavor you will extract from the bean.
If the French press method has been cited as being less efficient, it is probably because the grind for a French press is fairly coarse.
A drip brewer, by contrast, uses a finer grind and theoretically is more efficient for that reason. That said, a cheaper drip brewer might do a poor job of bringing the water into contact with all the coffee in the filter basket.
So there are no absolutes here.
Hope this helps.