The starter can be done at room temperature- because you're not making beer, you're growing yeast.
What I like to do is make my starter about 6-7 days in advance. Then, the next day, add some more cooled wort to step it up. I might do that a couple of times until I have the correct sized starter for my brew. When it's all fermented out, I place it in the fridge. On brewday, I take it out and decant the spent wort, and let it warm to approx 48 degrees.
I chill my wort to 50 degrees, and then pitch the 48 degree starter into the slightly warmer wort. It's not much of a difference, but the yeast seem to love being placed into the ever-so-slightly warmer wort.
I always pitch cold. Always. Some will tell you to pitch at 70, and then bring it down. But my thinking goes against this for several reasons. One, fermentation is exothermic, and by the time you get an established fermentation down to 50 degrees (without shocking it), the fermentation will be basically over! Two, just my reasoning on how I pitch. When I make an ale, I don't pitch at 85, and then lower it to 65 degrees. That just doesn't seem like the best thing for the yeast and seems like you'd get off-flavors. So I don't do it for lagers, either. Three- some lagers produce significant sulfur and diacetyl at higher temperatures. So then you need a diacetyl rest. If you pitch cold, often times you don't get those off-flavors and I don't even do a diacetyl rest most of the time.
Anyway, I've heard that it's common both ways. But if you pitch enough healthy yeast (consult mrmalty.com 's pitching calculator) and give it enough time in the primary, then the results are great with pitching at fermentation temperatures.
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