Yeast are pretty forgiving, especially if you have ferm temp control. Which you do[emoji106]
So for the first few hours yeast stabilize and acclimate to the environment. If it’s cold they may slow down a bit. If it’s hot they run with it and take off. That’s not a substitute for a properly sized yeast pitch but it can help at times. Warming the yeast slightly keeps them happy.
Once they have gone through the lag phase they grow the population. Basically Darwin stuff but they’ll grow to fit the environment.
Those first stages are important for yeast health. A nice healthy population usually makes a good beer to style. By that I mean it produces the expected flavors and attenuation. (Usually, if you made a good recipe and brewed it right). ( keep em warming up)
Once that’s done they sit down to a feast and eat all the easy sugars or high krausen. They get hot and your chiller may run a bit. ( don’t let em get too hot)
A few days later they start to get hungry again but the simple sugars are gone and they are fat and lazy. So that’s when I’m looking at a gravity sample to see when it’s time for a d rest.
I keep them happy and let them work on the more complex sugars and as that process is completing your just about ready for the drest.
That’s when the party is over and they are burping and farting off flavors. We warm them up to help keep the metabolism up and help them recharge the battery and clean up off flavor precursors. ( last warm days before winter begins)
After that you can crash the temp to Lager.
I try to pay attention to the end of the D rest and I don’t rush this phase. I want a stable FG. If I crash early I’ve gotten off flavors that I probably caused as a shocked the yeast and they couldn’t finish up.
In my experience I like to warm at the beginning, limit things from getting too warm during high krausen then warm it a bit more before I Lager.