There are still big controversies about Grant's drinking. He had lots of political enemies in his own time, so there was plenty of dirt published about him. Those who suspect modern media accounts should do some reading in the 19th century press, which was highly and unembarrasedly biased often extremely so.

Recent biographies are all over the map. The most pre-eminent Grant scholar today is Brooks Simpson of Arizona State Univ., and he finds little truth in the reports of binge drinking. There is no documentation whatsoever that drinking led to his retirement from the Army in the early 1850s, although the gloomy winters in Humboldt County, CA, with his beloved Julia 2,000 miles away, certainly would drive most people to drink. (There are no reports of his drinking while he was stationed at Fort Vancouver, either, and he really liked that location.) Lots of rumors were spread by his enemies, so separating truth from rumor is difficult. The recent bio by Ron ("Hamilton") Chernow seems obsessed with the drinking issue and trying to psychoanalyze the guy from 150 years' distance. On the other hand, it gives a fair treatment of Grant's presidency.

Drinking--and plenty of it--was part of the culture back then, especially since water wasn't safe to drink. A man was expected to be able to "hold his likker." It does appear that Grant evidently had a low tolerance for alcohol and therefore avoided it on most occasions. He was subject to migraine headaches, which can mimic drunkenness. Many 19th century doctors prescribed alcohol for that condition (and almost everything else). which would have made things worse.

There are still books being published (one as recently as 2015) that attack Grant not just for drinking but for being an incompetent general (even though he won the war) and a corrupt president. However, the general opinion among recent Grant scholars has improved his standing among presidents from near the bottom 40 years ago to about the middle of the pack.

There are quite a few issues which Grant didn't address in his Memoirs. The recent Annotated issue of his memoirs addresses many of these, as does Simpson's biography, Ulysses S Grant: Triumph over Adversity. We who are interested in Grant are hoping that Dr. Simpson will issue the second volume of his biography soon--we've been waiting quite a few years!

The story of the writing of Grant's Memoirs is quite a tale. Having lost all his money in a really bad investment, Grant took to writing articles on the war. Samuel Clemens (Mark Twain) gave him a generous offer for his memoirs. Grant then was diagnosed with throat cancer (undoubtedly from all those cigars he smoked). He spent his last days concentrating on writing the Memoirs, despite the pain and weakness, to be sure Julia would have something to live on after his death. A great love story, those two!
_________________________
May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view--E. Abbey