Thanks for the advise. So how much more degrees does the temp rise. I use a thermostat to keep the beer at 22 degrees. But obv this doesn't cool it if it goes over 22 so maybe I need to set it to 16 or so to allow for the increase in temp from the yeast? What do u think?
Wort can rise up to 10F (~4C) above the air
temperature. So, if you are controlling the air temp to 22C then your beer is fermenting 2-4 C above that. That temp is okay after the vigorous ferment is over...but, it is too high during the first week of an ale. Fermenting above 70F (21C) will DEFINATELY produce Diacetyl during the early stages, the hotter the more it will produce. Carmel/Butter/Butterscotch flavor is almost certainly diacetyl.
The good thing about diacetyl is that the yeast will clean it up...if you give them a chance (time) after they begin to run out of sugars (2nd week onwards).
As Jomebrew says, a more ideal profile would start at 66F (19C) for the first week, and then slowing bring the temperature up to 71-72F (22C) for the remainder. This keeps the esters and diacetyl formation to a minimum during the early fermentation, and then when you warm them up it keeps them active (rather than go dormant) to clean up the diacetyl.
If you have a thermostat, you MAY be able to do this by taping the temp probe to the side of your vessel, and covering it with ~1in (2.5 cm) of foam type insulation. Then your heater will only come on when the BEER drops below the desired temp (instead of the AIR). If your thermostat can't relocate the temp probe...search homebrewtalk.com for STC-1000. Lots of good threads over there about how to make fermentation temp controllers using these. (They cost about $20 US). I use an STC-1000 with the probe taped to the side of my buckets, in this fashion.
I ferment at 66F for a week, then raise to 70F for ~three weeks. These temps are the actual BEER temp (not air)---as mentioned by everyone else. There's no magic about the 4 weeks. I could probably stop at 2 weeks. But, I'm never in that much of a rush. There's no danger in going 4 weeks...and it saves me the trouble of checking SG all the time to see if it has fermented out, yet.