According to an interview with SPIN magazine, “Sadie Sorceress” was one of a few songs that was the result of lockdown sampling. “One pandemic activity we dabbled in was trying to make music out of samples. I was doing dollar bin world music LP buying. I had to not know what it was. It had to be either one dollar or two dollars, and not in English. I was trying to figure out how to cut up samples and be creative with that. Cook and Joey and myself all fiddle around with that sort of thing, and that led to making ‘Sadie Sorceress,’ ‘The Grim Reaper’ and ‘Kepler-22b.’ Those were built out of samples that were chopped out of records we’d never heard before. They were all very fresh in that way.” As for the hip-hop elements of the track, he said “Amby has always had one foot in that world and has been super keen to pursue that with Gizz one day. That was making music out of samples, which is a piece of hip-hop culture. It just naturally evolved and the logical next step was to get some shrimp bars on there. It was a very natural thing.” The intro of “Sadie Sorceress” is a recreated sample of “Je ne suis rien sans toi” by French singer Mireille Mathieu, released in 1968. It’s a French reinterpretation of “I’m Coming Home,” a song written by John Mason and Leslie Reed which was famously sung by Tom Jones and became a hit in Europe. It seems that the band had a hard time contacting the rights holders as they tweeted asking anyone to help them get in contact with Sony Music France on January 16th, 2022. Both Mason and Reed would receive a songwriting credit on “Sadie Sorceress.”

The song features numerous vocal additions by Ambrose’s grandmother Millicent Smith. In the video The Making of Omnium Gatherum we get to see her record some lines for the song. A tweet from the band says that she was ninety-seven at the time, though an Instagram clip says she’s ninety-eight. Ambrose said on 2023-03-23 that when he first showed her the song, all she said was “that’s disgusting.” That said, she seems to have embraced her role as Sadie, appearing in Gizzymail 23 wearing a hip beanie and posing alongside Shrimpomaniac himself. Later in The Making of Omnium Gatherum the band is seen listening back to the song.

In the end, Ambrose (vocals), Joey (turntable/Mellotron/synthesizer), Stu (vocals/clavinet/turntable) would be the only members of the band to play on the track. It was recorded and produced by Stu and Joey but only mixed by Stu. The band teased the songs of Omnium Gatherum on Twitter through emojis. On February 2nd, the song’s title was represented by a princess and a crystal ball. On the 8th it was teased again, this time by a sad face, a plus symbol, an envelope and pair of eyes, another plus symbol, then an envelope with the letter E on it, a night sky and a sorceress. @pixelperfect24 guessed it correctly on the 8th. The song was released as part of Omnium Gatherum on April 22nd, 2022.