There are at least two bands called Simmer:
1. an ambient punk band from Cheshire, United Kingdom (http://simmeruk.bandcamp.com). Their album, Yellow Streak is now available through Dog Knight Productions.
2. a short-lived indie band from the small town of Joure, The Netherlands (1997-1998).
Initially (and very briefly) called Slide and fronted by singer, guitarist and songwriter Theo de Jong, Simmer released one album, the critically acclaimed but commercially unsuccesful Mothertongue (1997). .