This is based on a blues song Cream used to play called "Lawdy Mama." Felix Pappalardi, who produced the album, wrote new lyrics to the song with his wife, Gail Collins, and Eric Clapton worked out the arrangement and also sang lead. Pappalardi, Collins and Clapton are the credited writers on the song.
As for Pappalardi, he went on to form Mountain, a band he also produced. In 1983, he was shot and killed by Collins in a domestic dispute; Collins was found guilty of criminally negligent homicide.
When Cream performed the early version of this song as "Lawdy Mama," Clapton and bass player Jack Bruce would share lead vocals. The band recorded both "Lawdy Mama" and "Strange Brew" at Atlantic Studios in New York on April 3, 1967. The band had spent the previous week in the city, performing daily at the "Music In The Fifth Dimension" show at the RKO Theater. These shows were organized by the influential disc jockey Murray the K, and provided great exposure for Cream in America. Other acts on the bill for some of these shows: The Who, Wilson Pickett and the Lovin' Spoonful. Cream would complete the Disraeli Gears album when they returned to the United States the next month.
The lyrics refer to a female, which could mean drugs or be a more literal reference to a woman. Either way, she is "killing what's inside of you."
Cream had a very psychedelic sound, and this song was released in the Summer of Love, where it fit in quite well.
To craft "Strange Brew," producer Felix Pappalardi added Eric Clapton's vocal to a take of the band's recording of "Lawdy Mama," which appears as a bonus track on the 2004 re-release of Disraeli Gears, but didn't make the original album. Jack Bruce wasn't happy about this, especially since he wasn't able to re-record his bassline. To keep the tenuous peace in the band during Cream's reunion concerts in 2005, "Strange Brew" was omitted from their 19-song playlist, despite being one of their best known and loved songs.
Clapton got the idea for the album title after a roadie named Mick Turner told him about the derailleur gears on his bicycle. Derailleur, pronounced "Di-rail-yer," are the kind of gears commonly found on 10-speed bikes. The roadie pronounced it "Disraeli," which led to the title.
On Eric Clapton's Crossroads boxed set, this is placed next to "Lawdy Mama," the Blues song it is based on.
There is a movie called Strange Brew, but it has nothing to with the song. Made in 1983, it stars Rick Moranis and Dave Thomas as Canadian brothers who love beer.
The album didn't appear until November, 1967, but this song was issued as the first single in June of that year, reaching its UK peak of #17 on July 15. Disraeli Gears was Cream's second album; they would release two more before calling it quits.