Well before all 5222 registered members add their opinions, here's my experience.
Have changed my mind on the use of dried yeast. Used to pitch dry, used to pitch warm, it all made good beer. Have had little trouble with dried yeast, the exception being that US-56 changed about 18 months ago. Now it has a slimy krausen which lasts to the end of fermentation and sticks to the fermenter wall as the beer is drained, and it's less flocculant than it used to be, but still a great yeast used in the right style.
My experience in the past with yeast was that if you keep it around 32C it will breed fast, and work fast. My early working life was as a baker, for some time I worked in a country bakery with a wood fired oven. The master baker would make the dough and it would be ripe (yep you read correctly, there was a test for ripeness) and ready for secondary fermentation around 10 hours later. Long slow cool primary fermentation makes the best bread Boy! Over the years primary fermentation times reduced with the use of bread improvers (yeast nutrient) to 8 hours, 3 hours, then came instant doughs, using horsepower from machinery for conversion in place of the kinetic energy produced during primary fermentation. We used compressed yeast (not liquid yeast but not dried, it was slightly dehydrated to a firm paste like yeast) then eventually came dried yeast in the early 70's. Dried was more potent, higher cell count and worked best if rehydrated but could be used as was. Well that's how bread is made today, fast. We all eat it, in my opinion the 10 hour doughs made superior bread, bread judges would recognise the difference, but not that many people would want to pay more for such a difference. My point - slow controlled fermentation made better bread.
Have been playing around with all sorts of wort compositions, mash temps, fermentation temps, pitching temps etc for 12 months roughly using dried and liquid yeasts. When I use rehydrated dried yeast as per the manufacturers rehydration instructions (when I stir after 15 min I give a whisk to aerate then rest again) pitch about 2 below fermentation temp and attemporate the rehydrated yeast before pitching, I find that lag time is reduced, the fermentation is much more controlled. When I say that, I mean it's not all rip-tear-bust and done in 3 days. Have two beers (using dried yeast) fermenting now, one in primary (K97) is 1.050/1.010 and still going after 10 days in primary AA of 80.21%, the other in secondary (US-05) is 1.056/1.015 after 9 days (7 days primary 1.056/1.017) AA of 71.6% and still going. For my 2c worth, the beers fermented in this fashion are brighter (meaning less dull to the palate). Achieveable attenuation must take into account the fermentability of the wort, in the case of the beer fermented using US-05 the malt bill included 10% Crystal/Carapils and so would reduce the ability of the yeast to achive the higher end of its normal attenuative capability.
So to agree with many of the comments above, do it either way, pitch dried or rehydrate. A quick Google search should locate scientific support for not pitching dried into a starter, apparently one should rehydrate first. Haven't tested this out yet. In any case you'll make good beer, but will it be the best it can be? maybe you won't notice. Bit like wasting an expensive stereo on my 1$ ear
For some yeasts such as Nottingham there would be little to gain in rehydrating or making a starter, I think only two organisms would survive an atomic catastrophe, Nottingham Yeast and Cockroaches
Newcomers should just pitch dried, relax and have a home brew.
For the present I'm sticking with rehydration and the other processes, it makes enough of a difference to my beers for me to go the extra yard. Another procedure I've returned to is racking to secondary, this gives the yeast a litte revitalisation and helps with better attenuation. Also have found that dropping the beer (racking/aerating to a second vessel) after 24 hours active fermentation helps improve attenuation with some yeasts (only tested one liquid yeast on two occasions and one dried on one occasion so far).
Screwy
