History lesson on the importance of an hydrometer. It's your friend.
The hydrometer probably did more to form modern brewing methods and styles than any other piece of equipment. Previous to that Beer was generally brewed from one malt. Light, brown, dark etc. But with the hydrometer breweries found that the paler the malt the more efficient it was so the base malt was switched to a pale barley malt and characteristic gained from the use of "speciality" malts. Much the same as it still done today.
Good call on the reading BTW.