|Demo by Rivers Cuomo
The Yeastmaster is a cassette compilation by Rivers Cuomo, featuring demos recorded from 1990 through 1992. The compilation was partially released in 2020 as a part of the digital compilations Alone V: Before Weezer and Patrick & Rivers in 2020.
The Yeastmaster is a compilation of Yeastmaster Part 1 and Part 2. Yeastmaster Part 1 was first mentioned in the recording history.  And while the demos from Yeastmaster Part 2 are mentioned in the Recording History  they would not be known to be a part of Yeastmaster Part 2 would not be known until the songs were included on the 2020 compilations Alone V: Before Weezer and Patrick & Rivers. These songs feature a focus on songwriting, something Cuomo's previous tapes were not entirely focused on. This resulted in songs that Karl Koch described as "either somewhat bitter or really goofy." And while there is a focus on songwriting, there are also several things that Karl described as "not-really songs", though it is unknown what exactly all of them are, as not all of them have been released.
Yeastmaster Part 1
"instrumental 1", "reggae feel", "i v ii III", "Bushman", "Bored and Boring", and "Lethargic and Lethargicing" also appear on this tape, but the track positions of the songs are unknown
Yeastmaster Part 2